A positive Helicobacter pylori test is associated with low spondylarthritis incidence in a Danish historical cohort study.

Ankylosing spondylitis (AS) and undifferentiated spondylarthritis (uSpA) are related inflammatory diseases affecting the spine and joints with infections among possible etiological factors. Helicobacter pylori (H. pylori) may affect the development of inflammatory diseases. Thus, we hypothesized that H. pylori infection affects AS and uSpA development. This cohort study was performed in Denmark with 56,000 patients from primary health care centers who were enrolled when a UBT was performed. They were followed for a median time of 8 years. From nationwide administrative registries, we extracted personal, diagnostic, and treatment information. Prevalence at time of UBT was studied on enrollment using logistic regression and incidence in the follow-up time of 8 years after UBT was studied using Cox regression, comparing H. pylori positive and H. pylori negative patients and adjusting for confounding variables. The prevalence of AS at the time of the UBT was higher among H. pylori positive individuals (OR = 2.00, CI 1.17-3.41), but likely to be linked to confounding as trends disappeared when stratifying for country of birth. The incidence of AS after UBT was lower for individuals who were previously H. pylori positive (OR = 0.23, CI 0.06-0.93). A similar phenomenon was observed for uSpA. As a novel finding, after UBT, the previously H. pylori infected individuals had lower risk of developing AS and uSpA compared to non-infected. This finding may be caused by etiological effects of previous H. pylori infection or unknown confounders. This suggests that H. pylori may somehow be positively involved in the pathogenesis of AS and uSpA.

Socioeconomic Factors and Clinical Outcomes Among Patients With Heart Failure in a Universal Health Care System.

OBJECTIVES: This study examined the associations between socioeconomic factors (SEF), readmission, and mortality in patients with incident heart failure (HF) with reduced ejection fraction (HFrEF) in a tax-financed universal health care system. BACKGROUND: Lack of health insurance is considered a key factor in health inequality, leading to poor clinical outcomes. However, data are sparse for the association between SEF and clinical outcomes among patients with HF in countries with tax-financed health care systems. METHODS: A nationwide population-based cohort study of 17,122 patients with incident HFrEF was carried out. Associations were assessed between individual-level SEF (cohabitation status, education, and income) and all-cause, HF, and non-HF readmission and mortality within 1 to 30, 31 to 90, and 91 to 365 days, as well as hospital bed days within 1 year after HF diagnosis. RESULTS: Low income was associated with a higher risk of all-cause readmission (adjusted hazard ratio [HR]: 1.24; 95% confidence interval [CI]: 1.08 to 1.43) and non-HF readmission (HR: 1.36; 95% CI: 1.17 to 1.58) within days 31 to 90 as well as with a higher risk of all-cause (HR: 1.27; 95% CI: 1.14 to 1.41), HF (HR: 1.26; 95% CI: 1.02 to 1.55) and non-HF readmission (HR: 1.25; 95% CI: 1.12 to 1.39) within days 91 to 365. Low-income patients also had a higher use of hospital bed days and risk of mortality during follow-up. CONCLUSIONS: In a tax-financed universal health care system, low income was associated with a higher risk of all-cause and non-HF readmission within 1 to 12 months after HF diagnosis and with HF readmission within 3 to 12 months among patients with incident HFrEF. Low-income patients also had a higher number of hospital bed days and a higher rate of mortality during follow-up.

Cardiovascular and bleeding outcomes in a population-based cohort of patients with chronic immune thrombocytopenia.

Essentials Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by low platelet count. We conducted a cohort study of 3 584 chronic ITP patients from the Nordic countries. Cardiovascular events occurred across all platelet count levels. Cardiovascular or bleeding events were strong prognostic factors for all-cause mortality. Background Among patients with chronic immune thrombocytopenia (cITP), little is known regarding risk factors for cardiovascular and bleeding outcomes and how these events influence mortality. Objectives We examined the rate of cardiovascular events and bleeding requiring a hospital contact according to platelet count levels, as well as the prognostic impact of these events on all-cause mortality in adult patients with cITP. Methods We identified all cITP patients registered in the Nordic Country Patient Registry for Romiplostim during 1996 to 2015. Absolute risks and hazard ratios across platelet count levels based on Cox regression analysis were computed, adjusting for age, sex, prevalent/incident cITP, smoking, and comorbidities. We also compared all-cause mortality rates in cITP patients with and without cardiovascular and bleeding events. Results Among 3 584 cITP patients, 1-year risks were 1.9% for arterial cardiovascular events, 1.2% for venous thromboembolism, and 7.5% for bleeding. Rates of cardiovascular events were similar across platelet counts. Patients with platelet counts <50 × 109 /L had >2-fold higher rates of bleeding than patients with normal platelet counts. These associations were unchanged in time-varying analyses that considered changes in platelet counts during follow-up. Occurrences of cardiovascular and bleeding events were associated with 4-fold to 5-fold increases in 1-year mortality. Conclusions Among patients with cITP, the 1-year risks of cardiovascular events were 1% to 2%, while nearly 8% experienced a bleeding event within 1 year. Cardiovascular events occurred across all platelet levels, while low platelet counts were associated with increased hazards of bleeding. Cardiovascular and bleeding events were strong prognostic factors for mortality.

Increasing Risk of Hospital-Treated Infections and Community-Based Antibiotic Use After Hip Fracture Surgery: A Nationwide Study 2005-2016.

We aimed to examine trends in the incidence of treated infections following hip fracture surgery in Denmark from 2005 to 2016. We conducted a nationwide cohort study using individual-level linked data from Danish population-based registries. We calculated cumulative incidence considering death as competing risk and, based on the pseudo-observation method, risk ratios (RRs) with 95% confidence interval (CI) using the period 2005-2006 as a reference. RRs were adjusted for age, sex, and comorbidity. A total of 74,771 patients aged 65 years or older with first-time hip fracture surgery were included. The risk of postoperative (at 15, 30, 90, and 365 days) infections increased during 2005-2016. The 30-day cumulative incidence of all hospital-treated infections increased from 10.8% (95% CI, 10.2% to 11.3%) in 2005-2006 to 14.3% (95% CI, 13.7% to 15.0%) in 2015-2016 (adjusted RR 1.32; 95% CI, 1.23 to 1.42). Adjusted RR for 30-day hospital-treated pneumonia was 1.70 (95% CI, 1.49 to 1.92). The 30-day cumulative incidence of redeeming community-based antibiotic prescriptions increased from 17.5% (95% CI, 16.8% to 18.2%) in 2005-2006 to 27.1% (95% CI, 26.3% to 27.9%) in 2015-2016 (adjusted RR 1.54; 95% CI, 1.47 to 1.62). The largest increase was observed for broad-spectrum antibiotic use (adjusted RR 1.79; 95% CI, 1.68 to 1.90). During 2005-2016, risk of infections was substantially higher in hip fracture patients than in the general population. The risk of hospital-treated pneumonia and antibiotic prescriptions increased more over time among hip fracture patients. We found increased risks of postoperative treated infections following hip fracture surgery during the 12-year study period, which could not entirely be explained by similar infection trends in the general population. Given the high mortality following infections in the elderly, further research is needed to identify patients at increased risk to target preventive treatment and potentially reduce complications and mortality in hip fracture patients. © 2018 American Society for Bone and Mineral Research.

Selective serotonin reuptake inhibitor use in hip fracture patients: a Danish nationwide prevalence study.

Background and purpose - Selective serotonin reuptake inhibitors (SSRIs) are often used in the elderly and are associated with adverse effects. Therefore, it is important to ascertain the prevalence of SSRI use in fragile and surgery-treated hip fracture patients. Methods - This population-based prevalence study included Danish hip fracture patients aged ≥ 65 years operated in 2006-2016 (n = 68,607) and matched individuals from the background population (n = 343,020). Using Poisson regression, prevalence risk ratios (PRRs) with 95% confidence intervals (CIs) were estimated to compare hip fracture patients with the general population, and to estimate the association between hip fracture patient characteristics and SSRI prescriptions. Results - The prevalence of SSRI use among hip fracture patients was 23% compared with 12% in the general population. During 2006-2016, the prevalence decreased from 26% to 18% among hip fracture patients and from 13% to 10% in the general population. Factors associated with SSRI use in hip fracture patients were age 75-84 years (PRR 1.18, CI 1.13-1.23), age ≥ 85 years (PRR 1.17, CI 1.11-1.22), female sex (PRR 1.13, CI 1.09-1.17), unmarried status (PRR 1.15, CI 1.11-1.19), living in a residential institution (PRR 2.30, CI 2.19-2.40), Charlson comorbidity index (CCI) score 1-2 (PRR 1.50, CI 1.45-1.55), CCI score 3+ (PRR 1.62, CI 1.55-1.69), and several medications. Interpretation - The prevalence of SSRI use was high among hip fracture patients compared with the general population. Our data stress the importance of continued clinical awareness of frailty, comorbidity, and polypharmacy of hip fracture patients and the potentially adverse drug effects of SSRI treatment.

Use of prescription drugs and risk of postoperative red blood cell transfusion in breast cancer patients: a Danish population-based cohort study.

BACKGROUND: Several frequently used prescription drugs may affect bleeding risk. We investigated use of aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), selective serotonin reuptake inhibitors (SSRIs), and statins and risk of postoperative red blood cell transfusion in breast cancer patients. METHODS: Using Danish population-based registries, we identified a cohort of women who underwent surgery for primary breast cancer (n = 22,238) during 2005-2012 and ascertained their use of aspirin, NSAIDs, SSRIs, and statins. For each drug, patients were categorized as users if they filled ≥1 prescription in the 60 days prior to surgery. We calculated the 14-day risk of red blood cell transfusion and relative risks (RRs) with 95% confidence intervals (CIs), comparing users with nonusers for each drug and adjusting for age, cancer stage, and Charlson Comorbidity Index score. RESULTS: In our cohort, 1385 (6.2%) women were aspirin users, 1794 (8.0%) were NSAID users, 1110 (4.9%) were SSRI users, and 2053 (9.1%) were statin users. The overall risk of red blood cell transfusion was 1.3%. The 14-day risk of RBC transfusion was 3.5% among aspirin users versus 1.1% among aspirin nonusers (adjusted RR = 1.9, 95% CI: 1.4-2.7), and 1.8% among SSRI users versus 1.2% among SSRI nonusers (adjusted RR = 1.2, 95% CI: 0.7-1.9). Red blood cell transfusion risk was increased among NSAID users, but not in a sensitivity analysis with a 30-day exposure window. Red blood cell transfusion risk was not increased among SSRI and statin users. CONCLUSIONS: Primary breast cancer surgery confers a low risk of RBC transfusion. Still, use of aspirin and possibly NSAIDs, but not SSRIs and statins, is associated with increased red blood cell transfusion. This increased risk is not explained by differences in age, stage, or comorbidity level.

Missing data and multiple imputation in clinical epidemiological research.

Missing data are ubiquitous in clinical epidemiological research. Individuals with missing data may differ from those with no missing data in terms of the outcome of interest and prognosis in general. Missing data are often categorized into the following three types: missing completely at random (MCAR), missing at random (MAR), and missing not at random (MNAR). In clinical epidemiological research, missing data are seldom MCAR. Missing data can constitute considerable challenges in the analyses and interpretation of results and can potentially weaken the validity of results and conclusions. A number of methods have been developed for dealing with missing data. These include complete-case analyses, missing indicator method, single value imputation, and sensitivity analyses incorporating worst-case and best-case scenarios. If applied under the MCAR assumption, some of these methods can provide unbiased but often less precise estimates. Multiple imputation is an alternative method to deal with missing data, which accounts for the uncertainty associated with missing data. Multiple imputation is implemented in most statistical software under the MAR assumption and provides unbiased and valid estimates of associations based on information from the available data. The method affects not only the coefficient estimates for variables with missing data but also the estimates for other variables with no missing data.