Socioeconomic gradient in mortality of working age and older adults with multiple long-term conditions in England and Ontario, Canada.

BACKGROUND: There is currently mixed evidence on the influence of long-term conditions and deprivation on mortality. We aimed to explore whether number of long-term conditions contribute to socioeconomic inequalities in mortality, whether the influence of number of conditions on mortality is consistent across socioeconomic groups and whether these associations vary by working age (18-64 years) and older adults (65 + years). We provide a cross-jurisdiction comparison between England and Ontario, by replicating the analysis using comparable representative datasets. METHODS: Participants were randomly selected from Clinical Practice Research Datalink in England and health administrative data in Ontario. They were followed from 1 January 2015 to 31 December 2019 or death or deregistration. Number of conditions was counted at baseline. Deprivation was measured according to the participant's area of residence. Cox regression models were used to estimate hazards of mortality by number of conditions, deprivation and their interaction, with adjustment for age and sex and stratified between working age and older adults in England (N = 599,487) and Ontario (N = 594,546). FINDINGS: There is a deprivation gradient in mortality between those living in the most deprived areas compared to the least deprived areas in England and Ontario. Number of conditions at baseline was associated with increasing mortality. The association was stronger in working age compared with older adults respectively in England (HR = 1.60, 95% CI 1.56,1.64 and HR = 1.26, 95% CI 1.25,1.27) and Ontario (HR = 1.69, 95% CI 1.66,1.72 and HR = 1.39, 95% CI 1.38,1.40). Number of conditions moderated the socioeconomic gradient in mortality: a shallower gradient was seen for persons with more long-term conditions. CONCLUSIONS: Number of conditions contributes to higher mortality rate and socioeconomic inequalities in mortality in England and Ontario. Current health care systems are fragmented and do not compensate for socioeconomic disadvantages, contributing to poor outcomes particularly for those managing multiple long-term conditions. Further work should identify how health systems can better support patients and clinicians who are working to prevent the development and improve the management of multiple long-term conditions, especially for individuals living in socioeconomically deprived areas.

Effect of a multimorbidity intervention on health care utilization and costs in Ontario: randomized controlled trial and propensity-matched analyses.

BACKGROUND: Patients with multimorbidity require coordinated and patient-centred care. Telemedicine IMPACT Plus provides such care for complex patients in Toronto, Ontario. We conducted a randomized controlled trial (RCT) comparing health care utilization and costs at 1-year postintervention for an intervention group and 2 control groups (RCT and propensity matched). METHODS: Data for 82 RCT intervention and 74 RCT control participants were linked with health administrative data. We created a second control group using health administrative data-derived propensity scores to match (1:5) intervention participants with comparators. We evaluated 5 outcomes: acute hospital admissions, emergency department visits, costs of all insured health care, 30-day hospital readmissions and 7-day family physician follow-up after hospital discharge using generalized linear models for RCT controls and generalized estimating equations for propensity-matched controls. RESULTS: There were no significant differences between intervention participants and either control group. For hospital admissions, emergency department visits, costs and readmissions, the relative differences ranged from 1.00 (95% confidence interval [CI] 0.39-2.60) to 1.67 (95% CI 0.82-3.38) with intervention costs at about Can$20 000, RCT controls costs at around Can$15 000 and propensity controls costs at around Can$17 000. There was a higher rate of follow-up with a family physician for the intervention participants compared with the RCT controls (53.13 v. 21.43 per 100 hospital discharges; relative difference 2.48 [95% CI 0.98-6.29]) and propensity-matched controls (49.94 v. 28.21 per 100 hospital discharges; relative difference 1.81 [95% CI 0.99-3.30]). INTERPRETATION: Despite a complex patient-centred intervention, there was no significant improvement in health care utilization or cost. Future research requires larger sample sizes and should include outcomes important to patients and the health care system, and longer follow-up periods. ONTARIO: ClinicalTrials.gov : 104191.

Associations between multiple long-term conditions and mortality in diverse ethnic groups.

BACKGROUND: Multiple conditions are more prevalent in some minoritised ethnic groups and are associated with higher mortality rate but studies examining differential mortality once conditions are established is US-based. Our study tested whether the association between multiple conditions and mortality varies across ethnic groups in England. METHODS AND FINDINGS: A random sample of primary care patients from Clinical Practice Research Datalink (CPRD) was followed from 1st January 2015 until 31st December 2019. Ethnicity, usually self-ascribed, was obtained from primary care records if present or from hospital records. Long-term conditions were counted from a list of 32 that have previously been associated with greater primary care, hospital admissions, or mortality risk. Cox regression models were used to estimate mortality by count of conditions, ethnicity and their interaction, with adjustment for age and sex for 532,059 patients with complete data. During five years of follow-up, 5.9% of patients died. Each additional condition at baseline was associated with increased mortality. The direction of the interaction of number of conditions with ethnicity showed a statistically higher mortality rate associated with long-term conditions in Pakistani, Black African, Black Caribbean and Other Black ethnic groups. In ethnicity-stratified models, the mortality rate per additional condition at age 50 was 1.33 (95% CI 1.31,1.35) for White ethnicity, 1.43 (95% CI 1.26,1.61) for Black Caribbean ethnicity and 1.78 (95% CI 1.41,2.24) for Other Black ethnicity. CONCLUSIONS: The higher mortality rate associated with having multiple conditions is greater in minoritised compared with White ethnic groups. Research is now needed to identify factors that contribute to these inequalities. Within the health care setting, there may be opportunities to target clinical and self-management support for people with multiple conditions from minoritised ethnic groups.

Looking beyond Administrative Health Care Data: The Role of Socioeconomic Status in Predicting Future High-cost Patients with Mental Health and Addiction.

INTRODUCTION: Previous research has shown that the socioeconomic status (SES)-health gradient also extends to high-cost patients; however, little work has examined high-cost patients with mental illness and/or addiction. The objective of this study was to examine associations between individual-, household- and area-level SES factors and future high-cost use among these patients. METHODS: We linked survey data from adult participants (ages 18 and older) of 3 cycles of the Canadian Community Health Survey to administrative health care data from Ontario, Canada. Respondents with mental illness and/or addiction were identified based on prior mental health and addiction health care use and followed for 5 years for which we ascertained health care costs covered under the public health care system. We quantified associations between SES factors and becoming a high-cost patient (i.e., transitioning into the top 5%) using logistic regression models. For ordinal SES factors, such as income, education and marginalization variables, we measured absolute and relative inequalities using the slope and relative index of inequality. RESULTS: Among our sample, lower personal income (odds ratio [OR] = 2.11, 95% confidence interval [CI], 1.54 to 2.88, for CAD$0 to CAD$14,999), lower household income (OR = 2.11, 95% CI, 1.49 to 2.99, for lowest income quintile), food insecurity (OR = 1.87, 95% CI, 1.38 to 2.55) and non-homeownership (OR = 1.34, 95% CI, 1.08 to 1.66), at the individual and household levels, respectively, and higher residential instability (OR = 1.72, 95% CI, 1.23 to 2.42, for most marginalized), at the area level, were associated with higher odds of becoming a high-cost patient within a 5-year period. Moreover, the inequality analysis suggested pro-high-SES gradients in high-cost transitions. CONCLUSIONS: Policies aimed at high-cost patients with mental illness and/or addiction, or those concerned with preventing individuals with these conditions from becoming high-cost patients in the health care system, should also consider non-clinical factors such as income as well as related dimensions including food security and homeownership.

Does Inpatient Palliative Care Facilitate Home-Based Palliative Care Postdischarge? A Retrospective Cohort Study.

Introduction: Evidence of the impact of inpatient palliative care on receiving home-based palliative care remains limited. Objectives: The objective of this study was to examine, at a population level, the association between receiving inpatient palliative care and home-based palliative care postdischarge. Design: We conducted a retrospective cohort study to examine the association between receiving inpatient palliative care and home-based palliative care within 21 days of hospital discharge among decedents in the last six months of life. Setting/Subjects: We captured all decedents who were discharged alive from an acute care hospital in their last 180 days of life between April 1, 2014, and March 31, 2017, in Ontario, Canada. The index event was the first hospital discharge furthest away from death (i.e., closest to 180 days before death). Results: Decedents who had inpatient palliative care were significantly more likely to receive home-based palliative care after discharge (80.0% vs. 20.1%; p < 0.001). After adjusting for sociodemographic and clinical covariates, the odds of receiving home-based palliative care were 11.3 times higher for those with inpatient palliative care (95% confidence interval [CI]: 9.4-13.5; p < 0.001). The strength of the association incrementally decreased as death approached. The odds of receiving home-based palliative care after a hospital discharge 60 days before death were 7.7 times greater for those who received inpatient palliative care (95% CI: 6.0-9.8). Conclusion: Inpatient palliative care offers a distinct opportunity to improve transitional care between hospital and home, through enhancing access to home-based palliative care.

Rising burden of multimorbidity and related socio-demographic factors: a repeated cross-sectional study of Ontarians.

OBJECTIVE: This study aimed to provide population-level data regarding trends in multimorbidity over 13 years. METHODS: We linked provincial health administrative data in Ontario, Canada, to create 3 cross-sectional panels of residents of any age in 2003, 2009, and 2016 to describe: (i) 13-year trends in multimorbidity prevalence and constellations among residents and across age, sex, and income; and (ii) chronic condition clusters. Multimorbidity was defined as having at least any 2 of 18 selected conditions, and further grouped into levels of 2, 3, 4, or 5 or more conditions. Age-sex standardized multimorbidity prevalence was estimated using the 2009 population as the standard. Clustering was defined using the observed combinations of conditions within levels of multimorbidity. RESULTS: Standardized prevalence of multimorbidity increased over time (26.5%, 28.8%, and 30.0% across sequential panels), across sex, age, and area-based income. Females, older adults and those living in lower income areas exhibited higher rates in all years. However, multimorbidity increased relatively more among males, younger adults, and those with 4 or 5 or more conditions. We observed numerous and increasing diversity in disease clusters, namely at higher levels of multimorbidity. CONCLUSION: Our study provides relevant and needed population-based information on the growing burden of multimorbidity, and related socio-demographic risk factors. Multimorbidity is markedly increasing among younger age cohorts. Also, there is an increasing complexity and lack of common clustering patterns at higher multimorbidity levels.

RéSUMé: OBJECTIF: Cette étude a pour but d'offrir des données populationnelles sur la multimorbidité et les tendances sur 13 années. MéTHODES: Cette étude transversale utilise des données administratives provinciales, incluant trois panels d'individus de tous âges, en 2003, 2009 et 2016, pour décrire : (i) les tendances de la multimorbidité en Ontario, et les différences entre âge, sexe et niveaux de revenus; ainsi que (ii) les combinaisons de maladies chroniques. La multimorbidité a été définie comme ayant au moins deux des 18 maladies chroniques sélectionnées, et ensuite groupée par niveau de 2, 3, 4 ou 5 maladies ou plus. Les taux de prévalence standardisés ont été estimés à partir de la population de 2009. Les combinaisons fréquentes de maladies chroniques observées par niveau de multimorbidité sont également arborées. RéSULTATS: La prévalence standardisée de multimorbidité a augmenté au fil des années (26,5 %, 28,8 % et 30,0 %). Elle était plus élevée chez les femmes, les personnes âgées, et celles vivant dans les endroits à faible revenus, peu importe l'année. Toutefois l'augmentation dans le temps était plus importante chez les hommes, les jeunes adultes, et pour les niveaux élevés de multimorbidité (4, 5 ou plus). Nous avons observé un nombre élevé de combinaisons de maladies, et une diversité grandissante spécialement pour les niveaux de multimorbidité élevés. CONCLUSION: Cette étude fournit des données épidémiologiques probantes sur le problème grandissant de la multimorbidité, notamment au sein des jeunes cohortes, et les facteurs sociodémographiques associés. Il existe également une complexité grandissante et pas de profils communs dans les combinaisons de maladies, aux niveaux élevés de multimorbidité.

Sex differences in multimorbidity and polypharmacy trends: A repeated cross-sectional study of older adults in Ontario, Canada.

BACKGROUND: Multimorbidity is increasing among older adults, but the impact of these recent trends on the extent and complexity of polypharmacy and possible variation by sex remains unknown. We examined sex differences in multimorbidity, polypharmacy (5+ medications) and hyper-polypharmacy (10+ medications) in 2003 vs 2016, and the interactive associations between age, multimorbidity level, and time on polypharmacy measures. METHODS AND FINDINGS: We employed a repeated cross-sectional study design with linked health administrative databases for all persons aged ≥66 years eligible for health insurance in Ontario, Canada at the two index dates. Descriptive analyses and multivariable logistic regression models were conducted; models included interaction terms between age, multimorbidity level, and time period to estimate polypharmacy and hyper-polypharmacy probabilities, risk differences and risk ratios for 2016 vs 2003. Multimorbidity, polypharmacy and hyper-polypharmacy increased significantly over the 13 years. At both index dates prevalence estimates for all three were higher in women, but a greater absolute increase in polypharmacy over time was observed in men (6.6% [from 55.7% to 62.3%] vs 0.9% [64.2%-65.1%] for women) though absolute increases in multimorbidity were similar for men and women (6.9% [72.5%-79.4%] vs 6.2% [75.9%-82.1%], respectively). Model findings showed that polypharmacy decreased over time among women aged < 90 years (especially for younger ages and those with fewer conditions), whereas it increased among men at all ages and multimorbidity levels (with larger absolute increases typically at older ages and among those with 4 or fewer conditions). CONCLUSIONS: There are sex and age differences in the impact of increasing chronic disease burden on changes in measures of multiple medication use among older adults. Though the drivers and health consequences of these trends warrant further investigation, the findings support the heterogeneity and complexity in the evolving association between multimorbidity and polypharmacy measures in older populations.

Association between continuity of care and subsequent diagnosis of multimorbidity in Ontario, Canada from 2001-2015: A retrospective cohort study.

BACKGROUND: Continuity of care is a well-recognized principle of the primary care discipline owing to its medical, interpersonal, and cost-saving benefits. Relationship continuity or the ongoing therapeutic relationship between a patient and their physician is a particularly desirable goal, but its role in preventing the accumulation of chronic conditions diagnoses in individuals is unknown. The objective of this study was to investigate the effect of continuity of care with physicians on the rate of incident multimorbidity diagnoses in patients with existing conditions. METHODS: This was a population-based, retrospective cohort study from 2001 to 2015 that focused on patients aged 18 to 105 years with at least one chronic condition (n = 166,665). Our primary exposure was relationship continuity of care with general practitioners and specialists measured using the Bice-Boxerman Continuity of Care Index (COCI). COCI was specified as a time-dependent exposure prior to the observation period. Our outcomes of interest were the time to diagnosis of a second, third, and fourth chronic condition estimated using cause-specific hazard regressions accounting for death as a competing risk. FINDINGS: We observed that patients with a single chronic condition and high continuity of care (>0.50) were diagnosed with a second chronic condition or multimorbidity at an 8% lower rate compared to individuals with low continuity (cause-specific hazard ratio (HR) 0.92 (95% Confidence Interval 0.90-0.93; p<0.0001) after adjusting for age, sex, income, place of residence, primary care enrolment, and the annual number of physician visits. Continuity remained protective as the degree of multimorbidity increased. Among patients with two conditions, the risk of diagnosis of a third chronic condition was also 8% lower for individuals with high continuity (HR 0.92; CI 0.90-0.94; p<0.0001). Patients with three conditions and high continuity had a 9% lower risk of diagnosis with a fourth condition (HR 0.91; CI 0.89-0.93; p<0.0001). CONCLUSIONS: Continuity of care is a potentially modifiable health system factor that reduces the rate at which diagnoses of chronic conditions are made over time in patients with multimorbidity. Additional research is needed to explain the underlying mechanisms through which continuity is related to a protective effect and the clinical sequalae.

Persistent socioeconomic inequalities in location of death and receipt of palliative care: A population-based cohort study.

BACKGROUND: Providing equitable care to patients in need across the life course is a priority for many healthcare systems. AIM: To estimate socioeconomic inequality trends in the proportions of decedents that died in the community and that received palliative care within 30 days of death (including home visits and specialist/generalist physician encounters). DESIGN: Cohort study based on health administrative data. Socioeconomic position was measured by area-level material deprivation. Inequality gaps were quantified annually and longitudinally using the slope index of inequality (absolute gap) and relative index of inequality (relative gap). SETTING/PARTICIPANTS: A total of 729,290 decedents aged ⩾18 years in Ontario, Canada from 2009 to 2016. RESULTS: In 2016, the modelled absolute gap (corresponding 95% confidence interval) between the most- and least-deprived neighbourhoods in community deaths was 4.0% (2.9-5.1%), which was 8.6% (6.2-10.9%) of the overall mean (46.6%). Relative to 2009, these inequalities declined modestly. Inequalities in 2016 were evident for palliative home visits (6.8% (5.8-7.8%) absolute gap, 26.3% (22.5-30.0%) relative gap) and for physician encounters (6.8% (5.7-7.9%) absolute gap, 13.2% (11.0-15.3%) relative gap), and widened from 2009 for physician encounters only on the absolute scale. Inequalities varied considerably across disease trajectories (organ failure, terminal illness, frailty, and sudden death). CONCLUSION: Key measures of end-of-life care are not achieved equally across socioeconomic groups. These data can be used to inform policy strategies to improve delivery of palliative and end-of-life services.

Direct and indirect pathways between low income status and becoming a high-cost health care user in Ontario, Canada: a mediation analysis of health risk behaviors.

PURPOSE: We investigated natural direct and indirect pathways between low-income status and high-cost user (HCU) transitions considering health risk behaviors as potential mediators. METHODS: We analyzed data from respondents (aged 18+) from four pooled cycles of the Canadian Community Health Survey (2005-2010/2011) linked to administrative data in Ontario, Canada. HCUs were defined as the top 5% of the population, ranked by cost consumption in any of the five years after survey interview. Low-income status was defined from the provincial distribution of self-reported household income, with missing values imputed from neighborhood-level data. In mediation analyses based on marginal structural models, we quantified the contributions of smoking, physical inactivity, alcohol consumption, and body mass index to income-HCU associations. RESULTS: 115,091 respondents (representative of 9,661,764 Ontarians) were included in the study, of which 7.2% became HCUs. The odds of becoming HCUs were 1.36 times (95% CI: 1.25-1.48) greater for low (vs. high) income status respondents. Smoking, physical activity, alcohol consumption, and body mass index contributed 9.4%, 6.5%, 10.6%, and 4.4% to this association, respectively. Tests for exposure-mediator interactions were not statistically significant. CONCLUSIONS: Health risk behaviors only partially explain income inequalities in future HCU transitions.

Joint impact of dementia and frailty on healthcare utilisation and outcomes: a retrospective cohort study of long-stay home care recipients.

OBJECTIVES: To examine the associations between dementia and 1-year health outcomes (urgent hospitalisation, long-term care (LTC) admission, mortality) among long-stay home care recipients and the extent to which these associations vary by clients' frailty level. DESIGN: A retrospective cohort study using linked clinical and health administrative databases. SETTING: Home care in Ontario, Canada. PARTICIPANTS: Long-stay (≥60 days) care clients (n=153 125) aged ≥50 years assessed between April 2014 and March 2015. MAIN OUTCOME MEASURES: Dementia was ascertained with a validated administrative data algorithm and frailty with a 66-item frailty index (FI) based on a previously validated FI derived from the clinical assessment. We examined associations between dementia, FI and their interactions, with 1-year outcomes using multivariable Fine-Gray competing risk (urgent hospitalisation and LTC admission) and Cox proportional hazards (mortality) models. RESULTS: Clients with dementia (vs without) were older (mean±SD, 83.3±7.9 vs 78.9±11.3 years, p<0.001) and more likely to be frail (30.3% vs 24.2%, p<0.001). In models adjusted for FI (as a continuous variable) and other confounders, clients with dementia showed a lower incidence of urgent hospitalisation (adjusted subdistribution HR (sHR)=0.84, 95% CI: 0.83 to 0.86) and mortality rate (adjusted HR=0.87, 95% CI: 0.84 to 0.89) but higher incidence of LTC admission (adjusted sHR=2.60, 95% CI: 2.53 to 2.67). The impact of dementia on LTC admission and mortality was significantly modified by clients' FI (p<0.001 interaction terms), showing a lower magnitude of association (ie, attenuated positive (for LTC admission) and negative (for mortality) association) with increasing frailty. CONCLUSIONS: The strength of associations between dementia and LTC admission and death (but not urgent hospitalisation) among home care recipients was significantly modified by their frailty status. Understanding the public health impact of dementia requires consideration of frailty levels among older populations, including those with and without dementia and varying degrees of multimorbidity.

The Incremental Health Care Costs of Frailty Among Home Care Recipients With and Without Dementia in Ontario, Canada: A Cohort Study.

OBJECTIVE: In this study, we investigated the incremental 1-year direct costs of health care associated with frailty among home care recipients in Ontario with and without dementia. METHODS: We conducted a cohort study of 159,570 home care clients aged 50 years and older in Ontario, Canada in 2014/2015. At index home care assessment, we ascertained dementia status using a validated algorithm and frailty level (robust, prefrail, frail) based on the proportion of accumulated to potential health deficits. Clients were followed for 1-year during which we obtained direct overall and sector-specific publicly-funded health care costs (in 2015 Canadian dollars). We estimated the incremental effect of frailty level on costs using a 3-part survival- and covariate-adjusted estimator. All analyses were stratified by dementia status. RESULTS: Among those with dementia (n=42,828), frailty prevalence was 32.1% and the average 1-year cost was $30,472. The incremental cost of frailty (vs. robust) was $10,845 [95% confidence interval (CI): $10,112-$11,698]. Among those without dementia (n=116,742), frailty prevalence was 25.6% and the average 1-year cost was $28,969. Here, the incremental cost of frailty (vs. robust) was $12,360 (95% CI: $11,849-$12,981). Large differences in survival between frailty levels reduced incremental cost estimates, particularly for the dementia group (survival effect: -$2742; 95% CI: -$2914 to -$2554). CONCLUSIONS: Frailty was associated with greater 1-year health care costs for persons with and without dementia. This difference was driven by a greater intensity of health care utilization among frail clients. Mortality differences across the frailty levels mitigated the association especially among those with dementia.

Variation in the health outcomes associated with frailty among home care clients: relevance of caregiver distress and client sex.

BACKGROUND: The identification of contextual factors that modify associations between client frailty and their health and service use outcomes is essential for informed home health care and policy planning. Our objective was to examine variation in the associations between frailty and select 1-year health outcomes by caregiver distress and client sex among community-residing older care recipients. METHODS: We conducted a retrospective cohort study using linked population-based clinical and health administrative databases for all long-stay home care clients (n = 234,552) aged 66+ years assessed during April 2010-2013 in Ontario, Canada. Frailty was assessed using a previously validated 72-item frailty index (FI). Presence of caregiver distress was derived from clinical assessment items administered by trained home care assessors. Multivariable log-binomial regression models were used to examine variations in the associations between frailty and outcomes of interest (mortality, nursing home [NH] placement, all-cause and prolonged hospitalization) by caregiver distress, with further model stratification by client sex. RESULTS: Frailty prevalence varied little by sex (19.3% women, 19.9% men) despite significant sex-differences in clients' sociodemographic and health characteristics. In both sexes, frailty was significantly associated with all outcomes, particularly NH placement (RR = 3.84, 95%CI 3.75-3.93) and death (RR = 2.32, 95%CI 2.27-2.37), though risk ratios were greater for women. Caregiver distress was more common with increasing frailty and for male clients, and a significant independent predictor of NH placement and prolonged hospitalization in both sexes. The association between frailty and NH placement (but not other outcomes) varied by caregiver distress for both men and women (p < 0.001 interaction terms), showing a greater magnitude of association among clients without (vs. with) a distressed caregiver. CONCLUSIONS: As caregiver distress varies by client sex, represents a key driver of NH placement (even among relatively robust clients), and modifies the impact of other risk factors such as frailty, it should be routinely assessed. Further, sex-differences should be considered when developing and evaluating community-based services for older adults and their caregivers.

Income inequalities in multimorbidity prevalence in Ontario, Canada: a decomposition analysis of linked survey and health administrative data.

BACKGROUND: The burden of multimorbidity is a growing clinical and health system problem that is known to be associated with socioeconomic status, yet our understanding of the underlying determinants of inequalities in multimorbidity and longitudinal trends in measured disparities remains limited. METHODS: We included all adult respondents from four cycles of the Canadian Community Health Survey (CCHS) (between 2005 to 2011/12), linked at the individual-level to health administrative data in Ontario, Canada (pooled n = 113,627). Multimorbidity was defined at each survey response as having ≥2 (of 17) high impact chronic conditions, based on claims data. Using a decomposition method of the Erreygers-corrected concentration index (CErreygers), we measured household income inequality and the contribution of the key determinants of multimorbidity (including socio-demographic, socio-economic, lifestyle and health system factors) to these disparities. Differences over time are described. We tested for statistically significant changes to measured inequality using the slope index (SII) and relative index of inequality (RII) with a 2-way interaction on pooled data. RESULTS: Multimorbidity prevalence in 2011/12 was 33.5% and the CErreygers was - 0.085 (CI: -0.108 to - 0.062), indicating a greater prevalence among lower income groups. In decomposition analyses, income itself accounted more than two-thirds (69%) of this inequality. Age (21.7%), marital status (15.2%) and physical inactivity (10.9%) followed, and the contribution of these factors increased from baseline (2005 CCHS survey) with the exception of age. Other lifestyle factors, including heavy smoking and obesity, had minimal contribution to measured inequality (1.8 and 0.4% respectively). Tests for trends (SII/RII) across pooled survey data were not statistically significant (p = 0.443 and 0.405, respectively), indicating no change in inequalities in multimorbidity prevalence over the study period. CONCLUSIONS: A pro-rich income gap in multimorbidity has persisted in Ontario from 2005 to 2011/12. These empirical findings suggest that to advance equality in multimorbidity prevalence, policymakers should target chronic disease prevention and control strategies focused on older adults, non-married persons and those that are physically inactive, in addition to addressing income disparities directly.

Primary care and health inequality: Difference-in-difference study comparing England and Ontario.

BACKGROUND: It is not known whether equity-oriented primary care investment that seeks to scale up the delivery of effective care in disadvantaged communities can reduce health inequality within high-income settings that have pre-existing universal primary care systems. We provide some non-randomised controlled evidence by comparing health inequality trends between two similar jurisdictions-one of which implemented equity-oriented primary care investment in the mid-to-late 2000s as part of a cross-government strategy for reducing health inequality (England), and one which invested in primary care without any explicit equity objective (Ontario, Canada). METHODS: We analysed whole-population data on 32,482 neighbourhoods (with mean population size of approximately 1,500 people) in England, and 18,961 neighbourhoods (with mean population size of approximately 700 people) in Ontario. We examined trends in mortality amenable to healthcare by decile groups of neighbourhood deprivation within each jurisdiction. We used linear models to estimate absolute and relative gaps in amenable mortality between most and least deprived groups, considering the gradient between these extremes, and evaluated difference-in-difference comparisons between the two jurisdictions. RESULTS: Inequality trends were comparable in both jurisdictions from 2004-6 but diverged from 2007-11. Compared with Ontario, the absolute gap in amenable mortality in England fell between 2004-6 and 2007-11 by 19.8 per 100,000 population (95% CI: 4.8 to 34.9); and the relative gap in amenable mortality fell by 10 percentage points (95% CI: 1 to 19). The biggest divergence occurred in the most deprived decile group of neighbourhoods. DISCUSSION: In comparison to Ontario, England succeeded in reducing absolute socioeconomic gaps in mortality amenable to healthcare from 2007 to 2011, and preventing them from growing in relative terms. Equity-oriented primary care reform in England in the mid-to-late 2000s may have helped to reduce socioeconomic inequality in health, though other explanations for this divergence are possible and further research is needed on the specific causal mechanisms.

Use of hospital-related health care among Health Links enrollees in the Central Ontario health region: a propensity-matched difference-in-differences study.

BACKGROUND: Health Links are a new model of providing care coordination for high-cost, high-needs patients in Ontario. We evaluated use of hospital-related health care services among Health Links patients in the Central Local Health Integration Network (LHIN) of Ontario in the year before versus after program enrolment and compared rates of use with those among similar patients with complex needs not enrolled in the program (comparator group). METHODS: We identified all patients who received a Health Links coordinated care plan before Jan. 1, 2015, using linked registry and health administrative data. We used propensity scores to match (1:1) enrollees (registry) with comparator patients (administrative data). Using a difference-in-differences approach with generalized estimating equations, we evaluated 5 measures of Health Link performance: rates of hospital admission, emergency department visits, days in acute care, 30-day readmissions and 7-day postdischarge primary care follow-up. RESULTS: Of the 344 enrollees in the registry, we matched 313 [91.0%] to comparator patients. All measured sociodemographic, comorbidity and health care use characteristics were balanced between the 2 groups (all standardized differences < 0.10). For enrollees, the rate of days in acute care per person-year increased by 35% (incidence rate ratio 1.35 [confidence interval 1.11-1.65]) after versus before the index date, but differences were nonsignificant for all other measures. Difference-in-differences analyses revealed greater reductions in hospital admissions, emergency department visits and acute care days after the index date in the comparator group than among enrollees. INTERPRETATION: Initial implementation of the Health Link program in the Central LHIN did not reduce selected indicators of Health Link performance among enrollees. As the Health Link program evolves and standardization is implemented, future research may reveal effects from the initiative in other outcomes or with longer follow-up.

Multimorbidity and healthcare utilization among home care clients with dementia in Ontario, Canada: A retrospective analysis of a population-based cohort.

BACKGROUND: For community-dwelling older persons with dementia, the presence of multimorbidity can create complex clinical challenges for both individuals and their physicians, and can contribute to poor outcomes. We quantified the associations between level of multimorbidity (chronic disease burden) and risk of hospitalization and risk of emergency department (ED) visit in a home care cohort with dementia and explored the role of continuity of physician care (COC) in modifying these relationships. METHODS AND FINDINGS: A retrospective cohort study using linked administrative and clinical data from Ontario, Canada, was conducted among 30,112 long-stay home care clients (mean age 83.0 ± 7.7 y) with dementia in 2012. Multivariable Fine-Gray regression models were used to determine associations between level of multimorbidity and 1-y risk of hospitalization and 1-y risk of ED visit, accounting for multiple competing risks (death and long-term care placement). Interaction terms were used to assess potential effect modification by COC. Multimorbidity was highly prevalent, with 35% (n = 10,568) of the cohort having five or more chronic conditions. In multivariable analyses, risk of hospitalization and risk of ED visit increased monotonically with level of multimorbidity: sub-hazards were 88% greater (sub-hazard ratio [sHR] = 1.88, 95% CI: 1.72-2.05, p < 0.001) and 63% greater (sHR = 1.63; 95% CI: 1.51-1.77, p < 0.001), respectively, among those with five or more conditions, relative to those with dementia alone or with dementia and one other condition. Low (versus high) COC was associated with an increased risk of both hospitalization and ED visit in age- and sex-adjusted analyses only (sHR = 1.11, 95% CI: 1.07-1.16, p < 0.001, for hospitalization; sHR = 1.07, 95% CI: 1.03-1.11, p = 0.001, for ED visit) but did not modify associations between multimorbidity and outcomes (Wald test for interaction, p = 0.566 for hospitalization and p = 0.637 for ED visit). The main limitations of this study include use of fixed (versus time-varying) covariates and focus on all-cause rather than cause-specific hospitalizations and ED visits, which could potentially inform interventions. CONCLUSIONS: Older adults with dementia and multimorbidity pose a particular challenge for health systems. Findings from this study highlight the need to reshape models of care for this complex population, and to further investigate health system and other factors that may modify patients' risk of health outcomes.

How Reliable Are Administrative Data for Capturing Stroke Patients and Their Care.

BACKGROUND/AIMS: The reliability of diagnostic coding of acute stroke and transient ischemic attack (TIA) in administrative data is uncertain. The purpose of this study is to determine the agreement between administrative data sources and chart audit for the identification of stroke type, stroke risk factors, and the use of hospital-based diagnostic procedures in patients with stroke or TIA. METHODS: Medical charts for a population-based sample of patients (n = 14,508) with ischemic stroke, intracerebral hemorrhage (ICH), or TIA discharged from inpatient and emergency departments (ED) in Ontario, Canada, between April 1, 2012 and March 31, 2013, were audited by trained abstractors. Audited data were linked and compared with hospital administrative data and physician billing data. The positive predictive value (PPV) of hospital administrative data and kappa agreement for the reporting of stroke type were calculated. Kappa agreement was also determined for stroke risk factors and for select stroke-related procedures. RESULTS: The PPV for stroke type in inpatient administrative data ranged from 89.5% (95% CI 88.0-91.0) for TIA, 91.9% (95% CI 90.2-93.5) for ICH, and 97.3% (95% CI 96.9-97.7) for ischemic stroke. For ED administrative data, PPV varied from 78.8% (95% CI 76.3-81.2) for ischemic, 86.3% (95% CI 76.8-95.7) for ICH, and 95.3% (95% CI 94.6-96.0) for TIA. The chance-corrected agreement between the audited and administrative data was good for atrial fibrillation (k = 0.60) and very good for diabetes (k = 0.86). Hospital administrative data combined with physician billing data more than doubled the observed agreement for carotid imaging (k = 0.65) and echocardiography (k = 0.66) compared to hospital administrative data alone. CONCLUSIONS: Inpatient and ED administrative data were found to be reliable in the reporting of the International Classification of Diagnosis, 10th revision, Canada (ICD-10-CA)-coded ischemic stroke, ICH and TIA, and for the recording of atrial fibrillation and diabetes. The combination of physician billing data with hospital administrative data greatly improved the capture of some diagnostic services provided to inpatients.

Accuracy of Administrative Data for the Coding of Acute Stroke and TIAs.

OBJECTIVE: Administrative data validation is essential for identifying biases and misclassification in research. The objective of this study was to determine the accuracy of diagnostic codes for acute stroke and transient ischemic attack (TIA) using the Ontario Stroke Registry (OSR) as the reference standard. METHODS: We identified stroke and TIA events in inpatient and emergency department (ED) administrative data from eight regional stroke centres in Ontario, Canada, from April of 2006 through March of 2008 using ICD-10-CA codes for subarachnoid haemorrhage (I60, excluding I60.8), intracerebral haemorrhage (I61), ischemic (H34.1 and I63, excluding I63.6), unable to determine stroke (I64), and TIA (H34.0 and G45, excluding G45.4). We linked administrative data to the Ontario Stroke Registry and calculated sensitivity and positive predictive value (PPV). RESULTS: We identified 5,270 inpatient and 4,411 ED events from the administrative data. Inpatient administrative data had an overall sensitivity of 82.2% (95% confidence interval [CI 95%]=81.0, 83.3) and a PPV of 68.8% (CI 95%=67.5, 70.0) for the diagnosis of stroke, with notable differences observed by stroke type. Sensitivity for ischemic stroke increased from 66.5 to 79.6% with inclusion of I64. The sensitivity and PPV of ED administrative data for diagnosis of stroke were 56.8% (CI 95%=54.8, 58.7) and 59.1% (CI 95%=57.1, 61.1), respectively. For all stroke types, accuracy was greater in the inpatient data than in the ED data. CONCLUSION: The accuracy of stroke identification based on administrative data from stroke centres may be improved by including I64 in ischemic stroke type, and by considering only inpatient data.