Comparison of the impact of the Atrial Fibrillation Follow-Up Investigation of Rhythm Management trial on prescribing patterns: a time-series analysis.

BACKGROUND: The AFFIRM (Atrial Fibrillation Follow-Up Investigation of Rhythm Management) trial demonstrated that rate control and rhythm control strategies result in similar survival and quality of life for patients with atrial fibrillation (AF). Because of superior safety and lower cost, rate control is now the recommended strategy for the management of most elderly, high-risk AF patients. OBJECTIVE: To determine the extent to which the AFFIRM trial results have been adopted into actual practice. METHODS: We conducted a time-series analysis of 3 population-based cohorts of patients with AF who were 66 years of age or older in Pennsylvania and Ontario. We stratified patients in Ontario by socioeconomic status (SES) and examined changes in quarterly prescription rates for rate control and rhythm controlling medications as well as cardioversion procedures before and after publication of the AFFIRM trial. RESULTS: The publication of the AFFIRM trial resulted in statistically significant reductions in the use of rhythm controlling medications in all 3 cohorts (p < 0.01). The magnitude of these changes in the non-low SES Canadian cohort was approximately 1% per quarter and was greater than the magnitude observed in the other cohorts (p < 0.001). The use of cardioversion procedures also decreased in all study regions (p < 0.01). In contrast, AFFIRM publication was also associated with a small increase in the use of rate controlling medications in Canada (p < 0.01) but not in the US (p = 0.23). CONCLUSIONS: Publication of the AFFIRM trial resulted in small but statistically significant changes in the care of patients with AF.

Pergolide associated cardiac valvulopathy based on Ontario administrative data.

INTRODUCTION: Pergolide is an ergot derived dopamine agonist that is widely used for the treatment of Parkinson's disease. Studies have found an association between pergolide and valvular heart abnormalities although there is still much to be learned about the clinical significance of the valvular changes, who is at risk, and whether there is duration of exposure effect. OBJECTIVE: To assess the long term risk of hospital admissions for valvular heart disease (VHD) or congestive heart failure (CHF, a clinically overt outcome of VHD) in new users of pergolide compared to new users of levodopa. The secondary objective was to assess whether there are any characteristics that can predict who is at higher risk of developing this outcome. DESIGN: Retrospective, population-based cohort study. SETTING: Ontario, Canada. SUBJECTS: Ontario residents aged 66 and older, newly started on treatment with either pergolide or levodopa. OUTCOMES: Admission to hospital with the most responsible diagnosis of congestive heart failure or valvular heart disease. RESULTS: The risk for admission for valvular heart disease or congestive heart failure were higher in those with 1-4 years exposure to pergolide compared with no exposure to pergolide (VHD: hazard ratio 2.4, p = 0.04; CHF: hazard ratio 1.6, p = 0.02). No such pattern was found with exposure to levodopa. CONCLUSION: Our study demonstrates that treatment with pergolide is associated with a higher risk of hospital admission for valvular heart disease or congestive heart failure and that this risk is greater in those with 1-4 years exposure than in those with less exposure. We did not find an increased risk beyond four years.

Antipsychotic therapy and short-term serious events in older adults with dementia.

BACKGROUND: Antipsychotic therapy is widely used to treat behavioral problems in older adults with dementia. Cohort studies evaluating the safety of antipsychotic therapy generally focus on a single adverse event. We compared the rate of developing any serious event, a composite outcome defined as an event serious enough to lead to an acute care hospital admission or death within 30 days of initiating antipsychotic therapy, to better estimate the overall burden of short-term harm associated with these agents. METHODS: In this population-based, retrospective cohort study, we identified 20 682 matched older adults with dementia living in the community and 20 559 matched individuals living in a nursing home between April 1, 1997, and March 31, 2004. Propensity-based matching was used to balance differences between the drug exposure groups in each setting. To examine the effects of antipsychotic drug use on the composite outcome of any serious event we used a conditional logistic regression model. We also estimated adjusted odds ratios using models that included all covariates with a standard difference greater than 0.10. RESULTS: Relative to those who received no antipsychotic therapy, community-dwelling older adults newly dispensed an atypical antipsychotic therapy were 3.2 times more likely (95% confidence interval, 2.77-3.68) and those who received conventional antipsychotic therapy were 3.8 times more likely (95% confidence interval, 3.31-4.39) to develop any serious event during the 30 days of follow-up. The pattern of serious events was similar but less pronounced among older adults living in a nursing home. CONCLUSIONS: Serious events, as indicated by a hospital admission or death, are frequent following the short-term use of antipsychotic drugs in older adults with dementia. Antipsychotic drugs should be used with caution even when short-term therapy is being prescribed.

A population-based study of cholinesterase inhibitor use for dementia.

OBJECTIVES: To examine current utilization patterns of cholinesterase inhibitor (ChEI) therapy for dementia to determine treatment duration, use in long-term care, how often patients receive these drugs until death, and frequency of switching between the available ChEIs. DESIGN: A population-based healthcare administrative database study. SETTING: Patients aged 66 and older from the Canadian province of Ontario who received a new prescription for a ChEI between June 1, 2000, and December 31, 2002. Patients were followed until discontinuation of ChEI therapy, death, or end of the observation period (March 31, 2005). PARTICIPANTS: Twenty-eight thousand nine hundred and sixty-one patients, including 4,601 residing in long-term care, mean age 80, 63% female. MEASUREMENTS: Information on diagnosis, medical comorbidity, physician visits, and concomitant medication use was obtained. Estimates of duration of continuous use were determined. The percentage of patients who remained on the initial dose prescribed, the proportion who switched to a second ChEI, and the percentage who remained on ChEIs until death were calculated. RESULTS: Patients had on average more than 26 physician visits in the year before ChEI therapy, but only 28% had seen a dementia specialist. Concomitant use of potentially inappropriate medications (strongly anticholinergic medications and benzodiazepines) was noted in 37% of patients. The average length of treatment for all patients was 866 days. Many patients (43%) remained on the initial dose prescribed, 6% switched to another ChEI, and 19% died while on ChEI therapy. CONCLUSION: Elderly patients with dementia are treated for lengthy periods of time with ChEIs in the community and in long-term care facilities. Further research is required to determine whether these utilization patterns are appropriate. It is also unclear whether these results are generalizable to other populations without universal health coverage or drug formulary benefits.

The effects of coxib formulary restrictions on analgesic use and cost: regional evidence from Canada.

BACKGROUND: Public insurance plans for pharmaceuticals in Canada differ substantially across provinces in the conditions under which pharmaceuticals are reimbursed. Coxibs provide a good example. Québec had no restrictions on reimbursement for these drugs. Ontario required physicians to submit the clinical indications for their use on the prescription. British Columbia required physicians to seek and receive prior authorisation from the drug plan. OBJECTIVE: This study compares the effects of different reimbursement policies on coxib, non-selective non-steroidal anti-inflammatory drugs (nsNSAIDs), and gastro-protective agent (GPA) use and cost. STUDY DESIGN: Analysis of retrospective time series analysis of all NSAID and GPA administrative claims data from April 1997 through December 2002. SETTING: Administrative claims data from April 1997 through December 2002 for each of the publicly funded drug plans in Québec, Ontario, and British Columbia. In addition, we obtained data from BC PharmaNet, which records all dispensed prescriptions in British Columbia. PATIENTS OR OTHER PARTICIPANTS: Senior beneficiaries (>or= 65 years). MAIN OUTCOME MEASURE: We compared the projected total NSAID utilisation in the absence of coxib reimbursement restriction with actual utilisation by province and drug category. Projected utilisation was based on ARIMA modelling and reported as the number of defined daily doses (DDDs) per 100 senior (>or=65 years) beneficiaries/month. RESULTS: In Ontario, under its "limited use" policy, uptake and steady-state use of coxibs was similar to that in Québec, where there were no restrictions. In British Columbia, publicly funded use of coxibs was 6% of that in Ontario and Québec. Despite a shift to private reimbursement, total coxib use in BC was only 50% of use in Ontario and Québec. The use of all NSAIDS (nsNSAIDS plus coxibs) increased for all provincial drug plans except for BC. The increase and overall rate of total NSAID use was greatest in Ontario. Neither Ontario's nor BC's policies had an impact on use of nsNSAIDs or GPAs. CONCLUSION: Only BC's policy effectively limited publicly funded coxib use. However, there was substantial cost-shifting to out-of-pocket and third party insurance plans in BC.

Antipsychotic drug use and mortality in older adults with dementia.

BACKGROUND: Antipsychotic drugs are widely used to manage behavioral and psychological symptoms in dementia despite concerns about their safety. OBJECTIVE: To examine the association between treatment with antipsychotics (both conventional and atypical) and all-cause mortality. DESIGN: Population-based, retrospective cohort study. SETTING: Ontario, Canada. PATIENTS: Older adults with dementia who were followed between 1 April 1997 and 31 March 2003. MEASUREMENTS: The risk for death was determined at 30, 60, 120, and 180 days after the initial dispensing of antipsychotic medication. Two pairwise comparisons were made: atypical versus no antipsychotic use and conventional versus atypical antipsychotic use. Groups were stratified by place of residence (community or long-term care). Propensity score matching was used to adjust for differences in baseline health status. RESULTS: A total of 27,259 matched pairs were identified. New use of atypical antipsychotics was associated with a statistically significant increase in the risk for death at 30 days compared with nonuse in both the community-dwelling cohort (adjusted hazard ratio, 1.31 [95% CI, 1.02 to 1.70]; absolute risk difference, 0.2 percentage point) and the long-term care cohort (adjusted hazard ratio, 1.55 [CI, 1.15 to 2.07]; absolute risk difference, 1.2 percentage points). Excess risk seemed to persist to 180 days, but unequal rates of censoring over time may have affected these results. Relative to atypical antipsychotic use, conventional antipsychotic use was associated with a higher risk for death at all time points. Sensitivity analysis revealed that unmeasured confounders that increase the risk for death could diminish or eliminate the observed associations. LIMITATIONS: Information on causes of death was not available. Many patients did not continue their initial treatments after 1 month of therapy. Unmeasured confounders could affect associations. CONCLUSIONS: Atypical antipsychotic use is associated with an increased risk for death compared with nonuse among older adults with dementia. The risk for death may be greater with conventional antipsychotics than with atypical antipsychotics.

Initiation of benzodiazepines in the elderly after hospitalization.

OBJECTIVE: To estimate the rate of new chronic benzodiazepine use after hospitalization in older adults not previously prescribed with benzodiazepines. DESIGN: Retrospective cohort study using linked, population-based administrative data. SETTING: Ontario, Canada between April 1, 1992 and March 31, 2005. PARTICIPANTS: Community-dwelling seniors who had not been prescribed benzodiazepine drugs in the year before hospitalization were selected from all 1.4 million Ontario residents aged 66 years and older. MAIN OUTCOME MEASURES: New chronic benzodiazepine users, defined as initiation of benzodiazepines within 7 days after hospital discharge and an additional claim within 8 days to 6 months. We used multivariate logistic regression to examine for the effect of hospitalization on the primary outcome after adjusting for confounders. RESULTS: There were 405,128 patient hospitalizations included in the cohort. Benzodiazepines were prescribed to 12,484 (3.1%) patients within 7 days of being discharged from hospital. A total of 6,136 (1.5%) patients were identified as new chronic benzodiazepine users. The rate of new chronic benzodiazepine users decreased over the study period from 1.8% in the first year to 1.2% in the final year (P < .001). Multivariate logistic regression found that women, patients admitted to the intensive care unit or nonsurgical wards, those with longer hospital stays, higher overall comorbidity, a prior diagnosis of alcoholism, and those prescribed more medications had significantly elevated adjusted odds ratios for new chronic benzodiazepine users. Older individuals had a lower risk for the primary outcome. CONCLUSION: New benzodiazepine prescription after hospitalization occurs frequently in older adults and may result in chronic use. A systemic effort to address this risky practice should be considered.

Variation in nursing home antipsychotic prescribing rates.

BACKGROUND: Excessive prescribing of antipsychotic therapy is a concern owing to their potential to cause serious adverse events. We explored variation in the use of antipsychotic therapy across nursing homes in Ontario, Canada, and determined if prescribing decisions were based on clinical indications. METHODS: A point-prevalence study of antipsychotic therapy use in 47 322 residents of 485 provincially regulated nursing homes in December 2003. Facilities were classified into quintiles according to their mean antipsychotic prescribing rates. Residents were grouped into those with a potential clinical indication or no identified clinical indication for antipsychotic therapy. RESULTS: A total of 15 317 residents (32.4%) were dispensed an antipsychotic agent. The mean rate of antipsychotic prescribing by home ranged from 20.9% in the quintile of facilities with the lowest mean prescribing rates (quintile 1) to 44.3% in facilities with the highest mean prescribing rates (quintile 5). Compared with individuals residing in nursing homes with the lowest mean antipsychotic prescribing rates, those residing in facilities with the highest rates were 3 times more likely to be dispensed an antipsychotic agent (adjusted odds ratio [AOR], 3.0; 95% confidence interval [CI], 2.74-3.19). Similar rates were observed among residents with psychoses with or without dementia (AOR, 2.7; 95% CI, 2.35-3.09) and residents without psychoses or dementia (AOR, 2.9; 95% CI, 2.19-3.81) who had no identifiable indication for an antipsychotic therapy. CONCLUSION: Residents in facilities with high antipsychotic prescribing rates were about 3 times more likely than those in facilities with low prescribing rates to be dispensed an antipsychotic agent, irrespective of their clinical indication.

Antipsychotic use in older adults with Parkinson's disease.

The choice of agents to treat psychotic symptoms in Parkinson's disease is important given the potential for antipsychotics to worsen Parkinsonism. The purpose of this study was to estimate the incidence of psychotic symptoms requiring treatment in individuals with Parkinson's disease after starting dopaminergic medications, and to describe the agents being selected as initial antipsychotic therapy. Using the administrative health care databases of Ontario, Canada, individuals 66 years of age or older with Parkinson's disease who were newly treated with dopaminergic agents were identified. Subsequent prescriptions for antipsychotic medications were then identified. A total of 10,347 older adults were newly started on dopaminergic agents between 1998 and 2003. The Kaplan-Meier estimate for the cumulative probability of requiring an antipsychotic at 7 years was 35%; 499 individuals (4.8%; 5.2/100 person-years) were prescribed an antipsychotic within 1 year of starting dopaminergic therapy. The proportion of initial antipsychotic prescriptions for typical antipsychotics decreased from 56% (42 of 75) in 1998 to 9% (8 of 88) in 2002. Antipsychotic use is common in individuals with Parkinsonism newly treated with dopaminergic medication. Typical antipsychotics are still commonly being chosen as first-line agents for older patients, indicating a need for interventions to improve practice.

Trends in deliveries, prenatal care, and obstetrical complications in women with pregestational diabetes: a population-based study in Ontario, Canada, 1996-2001.

OBJECTIVE: To describe recent trends in the proportion of deliveries in women with pregestational diabetes (PGD), their use of services, and diabetes-related obstetrical complications. RESEARCH DESIGN AND METHODS: In this population-based retrospective cohort study, comprehensive administrative data were used to identify all women (with and without PGD) who gave birth in an Ontario, Canada, hospital from 1996 to 2001. Data on maternal complications and interventions were obtained from hospital discharge records; data on use of prenatal services were obtained from fee-for-service claims. RESULTS: The proportion of deliveries in women with PGD increased steadily from 0.8% in 1996 to 1.2% in 2001 (P < 0.001). In 2001, women with PGD were more likely to be diagnosed with shoulder dystocia (adjusted odds ratio 2.00 [95% CI 1.55-2.58]), hypertension (4.13 [3.44-4.96]), and preeclampsia/eclampsia (4.44 [3.43-5.73]) and have higher rates of inductions (1.69 [1.52-1.88]) and caesarean sections (1.78 [1.60-1.98]) than women without PGD. In 2001, 50% of the women with PGD had a visit to a diabetes specialist during pregnancy and only 30% of women had claims for a prenatal retinal examination. Both of these rates have decreased over the study period. CONCLUSIONS: Women with PGD now account for a larger proportion of deliveries. These women continue to have higher obstetrical complication and intervention rates than women without PGD and many do not receive recommended specialty care during pregnancy.

The evaluation of a formalized queue management system for coronary angiography waiting lists.

BACKGROUND: Lengthy waiting lists for coronary angiography have been described in many health care systems worldwide. The extent to which formal queue management systems may improve the prioritization and survival of patients in the angiography queue is unknown. OBJECTIVE: To prospectively evaluate the performance of a formal queue management system for patients awaiting coronary angiography in Ontario. METHODS: The coronary angiography urgency scale, a formal queue management system developed in 1993 using a modified Delphi panel, allocates recommended maximum waiting times (RMWTs) in accordance with clinical necessity. By using a provincial clinical registry, 35,617 consecutive patients referred into the coronary angiography queue between April 1, 2001, and March 31, 2002, were prospectively tracked. Cox proportional hazards models were used to examined mortality risk across urgency after adjusting for additional clinical and comorbid factors. RESULTS: Good agreement was determined in urgency ratings between scores from the coronary angiography urgency scale and implicit physician judgement, which was obtained independently at the time of the index referral (weighted kappa = 0.49). The overall mortality in the queue was 0.3% (0.47%, 0.26% and 0.13% for urgent, semiurgent and elective patients, respectively). Urgency, as specified by the coronary angiography urgency scale, was the strongest predictor of death in the queue (P<0.001). However, when patients were censored according to their RMWTs, mortality was similar across different levels of urgency. Consequently, up to 18.5 deaths per 10,000 patients could have potentially been averted had patients been triaged and undergone coronary angiography within the RMWT as specified by the coronary angiography urgency scale. CONCLUSIONS: The incorporation of the coronary angiography urgency scale as a formal queue management system may decrease mortality in the coronary angiography queue. The authors recommend its implementation in health care systems where patients experience excessive waiting time delays for coronary angiography.

Atypical antipsychotics and parkinsonism.

BACKGROUND: Atypical antipsychotic agents are thought to be less likely than older typical agents to produce parkinsonism. This has not been well documented. We compared the risk of development of incident parkinsonism among older adults dispensed atypical relative to typical antipsychotics. METHODS: Retrospective cohort study of all adults 66 years and older in Ontario. We used Cox proportional hazards models to study the association between the type, potency, and dose of antipsychotic dispensed and the development of parkinsonism during 1 year of follow-up. RESULTS: All 25,769 older adults prescribed antipsychotics were observed for 11,573 person-years, and 449 events of parkinsonism were identified. Relative to individuals dispensed an atypical antipsychotic, those dispensed a typical agent were 30% more likely (adjusted hazard ratio [HR], 1.30; 95% confidence interval [CI], 1.04-1.58) and those exposed to neither agent were 60% less likely (HR, 0.40; 95% CI, 0.29-0.43) to experience development of parkinsonism. Furthermore, those dispensed lower-potency typical agents were no different (HR, 0.75; 95% CI, 0.48-1.15), and those dispensed higher-potency typical antipsychotics were at close to a 50% greater risk (HR, 1.44; 95% CI, 1.13-1.84) of development of parkinsonism relative to atypical antipsychotics. Relative to those dispensed a high-dose atypical antipsychotic, those dispensed a typical antipsychotic were at similar risk for parkinsonism (Wald chi(2) = 0.14, P = .7). CONCLUSIONS: The risk of development of parkinsonism associated with the use of high-dose atypical antipsychotics was similar to that associated with the use of typical antipsychotics. Caution should be used when prescribing atypical antipsychotic therapy at high doses.

Antipsychotic medications and drug-induced movement disorders other than parkinsonism: a population-based cohort study in older adults.

OBJECTIVES: To study the relationship between initiating therapy with an antipsychotic medication and a subsequent new diagnosis of a drug-induced movement disorder other than parkinsonism in older adults with dementia. DESIGN: Retrospective, population-based cohort study. SETTING: Ontario, Canada. PARTICIPANTS: Ontario residents aged 66 and older with a diagnosis of dementia newly started on treatment with typical or atypical antipsychotic therapy. MEASUREMENT: Estimated relative risk of developing a drug-induced movement other than parkinsonism in the 1-year follow-up period after starting therapy with an antipsychotic medication. RESULTS: From April 1, 1997, to March 31, 2001, 21, 835 older adults with dementia who were newly started on antipsychotic medications were identified. Nine thousand seven hundred ninety subjects were started on atypical antipsychotics and 12,045 subjects started on typical antipsychotics. Demographic characteristics were similar between the groups. There were 5.24 cases of tardive dyskinesia (TD) or other drug-induced movement disorder per 100 person-years on therapy with a typical antipsychotic and 5.19 cases per 100 person-years on therapy with an atypical antipsychotic. The risk of developing drug-induced movement disorder while being treated with an atypical agent was not statistically different from that with a typical antipsychotic (relative risk=0.99, 95% confidence interval=0.86-1.15; P<.93). CONCLUSION: Older adults with dementia who are treated with typical or atypical antipsychotic therapy are at risk for developing TD and other drug-induced movement disorders.

Incidence of delirium in older adults newly prescribed lithium or valproate: a population-based cohort study.

BACKGROUND: The use of lithium carbonate for the treatment of mood disorders in old age has decreased at a dramatic rate in favor of valproate. Because of lithium's narrow therapeutic range, neurotoxicity can be an important complication in lithium therapy and potentially influence prescription patterns. Therefore, we compared the incidence of delirium in older adults with mood disorders who were newly dispensed either lithium or valproate. METHOD: Using 4 population-based administrative databases from the province of Ontario, Canada (the Ontario Drug Benefit program, the Canadian Institute for Health Information, the Ontario Health Insurance Plan, and the Registered Persons Data Base), we were able to identify a cohort of mood disorder patients 66 years and older who were newly dispensed lithium or valproate over an 8-year period (1993-2001). Measures were taken to ensure that the sample was composed of mood disorder patients. As a comparator, we included a known deliriogenic drug, benztropine. The main outcome measure was a new diagnosis of delirium on a hospitalization record during 1 year of follow-up. RESULTS: Our study cohort consisted of 2422 new users of lithium and 2918 new users of valproate over an 8-year period. There was no statistically significant difference in the incidence of delirium between lithium (2.8 per 100 person-years) and valproate (4.1 per 100 person-years). Compared with patients who received lithium, patients who received benztropine had a significantly higher risk of delirium (p < .001). CONCLUSION: The incidence of hospitalizations with delirium was similar in patients treated with lithium and valproate. These findings add to the evidence suggesting that the shift away from the use of lithium carbonate to manage mood disorders in older adults is not justified on the basis of concerns of neurotoxicity.

New thyroxine treatment in older adults beginning lithium therapy: implications for clinical practice.

OBJECTIVE: The authors sought to determine the incidence of lithium-induced hypothyroidism in a population-based cohort of older adults beginning lithium therapy and thereby to inform clinical guidelines on the frequency of monitoring necessary in this group. METHODS: The authors conducted a population-based observational cohort study using four administrative databases that contained information on over 1.3 million older adults in Ontario who receive universal healthcare coverage in terms of physician services, drugs, and hospitalizations. Over an 18-month period, they studied adults age>or=65 who were newly prescribed lithium or valproate, monitoring subjects for initiation of T4 therapy (as a proxy for hypothyroidism) while they continued their lithium use. RESULTS: The authors identified 1,705 new users of lithium and 2,406 new users of valproate with similar baseline characteristics. Lithium users were significantly more likely to be treated with T4 than were valproate users. The rate of T4 treatment per 100 person-years was 5.65 in the lithium group and 2.70 in the valproate group. CONCLUSION: T4 treatment was initiated in almost 6% of lithium-treated patients, suggesting the possibility that hypothyroidism developed twice as frequently among these patients as would be expected among a mixed-age population. Increased vigilance and continued monitoring of thyroid functioning for at least 2 years is necessary in older adults beginning lithium therapy.

Atypical antipsychotic drugs and risk of ischaemic stroke: population based retrospective cohort study.

OBJECTIVE: To compare the incidence of admissions to hospital for stroke among older adults with dementia receiving atypical or typical antipsychotics. DESIGN: Population based retrospective cohort study. SETTING: Ontario, Canada. Patients 32,710 older adults (< or = 65 years) with dementia (17,845 dispensed an atypical antipsychotic and 14,865 dispensed a typical antipsychotic). MAIN OUTCOME MEASURES: Admission to hospital with the most responsible diagnosis (single most important condition responsible for the patient's admission) of ischaemic stroke. Observation of patients until they were either admitted to hospital with ischaemic stroke, stopped taking antipsychotics, died, or the study ended. RESULTS: After adjustment for potential confounders, participants receiving atypical antipsychotics showed no significant increase in risk of ischaemic stroke compared with those receiving typical antipsychotics (adjusted hazard ratio 1.01, 95% confidence interval 0.81 to 1.26). This finding was consistent in a series of subgroup analyses, including ones of individual atypical antipsychotic drugs (risperidone, olanzapine, and quetiapine) and selected subpopulations of the main cohorts. CONCLUSION: Older adults with dementia who take atypical antipsychotics have a similar risk of ischaemic stroke to those taking typical antipsychotics.