Retrospective Population-based Matched Cohort Study Research Articles

Asthma And Proinflammatory Conditions: A Population-based Retrospective Matched Cohort Study

Abstract Objective To determine the association between asthma and proinflammatory conditions. Participants and Methods This population-based retrospective matched cohort study enrolled all asthmatic patients among Rochester, Minnesota, residents between January 1, 1964, and December 31, 1983. For each asthmatic patient, 2 age-and sex-matched nonasthmatic individuals were drawn from the same population. The asthmatic and nonasthmatic cohorts were followed forward in the Rochester Epidemiology Project diagnostic index for inflammatory bowel disease (IBD), rheumatoid arthritis (RA), diabetes mellitus (DM), and coronary heart disease (CHD) as outcome events. Data were fitted to Cox proportional hazards models. Results We identified 2392 asthmatic patients and 4784 nonasthmatic controls. Of the asthmatic patients, 1356 (57%) were male, and mean age at asthma onset was 15.1 years. Incidence rates of IBD, RA, DM, and CHD in nonasthmatic controls were 32.8, 175.9, 132.0, and 389.7 per 100,000 person-years, respectively; those for asthmatic patients were 41.4, 227.9, 282.6, and 563.7 per 100,000 person-years, respectively. Asthma was associated with increased risks of DM (hazard ratio, 2.11; 95% confidence interval, 1.43-3.13; P P =.02) but not with increased risks of IBD or RA. Conclusion Although asthma is a helper T cell type 2–predominant condition, it may increase the risks of helper T cell type 1–polarized proinflammatory conditions, such as CHD and DM. Physicians who care for asthmatic patients need to address these unrecognized risks in asthmatic patients.

Mental health: A cause or consequence of injury? A population-based matched cohort study

BackgroundWhile a number of studies report high prevalence of mental health problems among injured people, the temporal relationship between injury and mental health service use has not been established. This study aimed to quantify this relationship using 10 years of follow-up on a population-based cohort of hospitalised injured adults.MethodsThe Manitoba Injury Outcome Study is a retrospective population-based matched cohort study that utilised linked administrative data from Manitoba, Canada, to identify an inception cohort (1988–1991) of hospitalised injured cases (ICD-9-CM 800–995) aged 18–64 years (n = 21,032), which was matched to a non-injured population-based comparison group (n = 21,032). Pre-injury comorbidity and post-injury mental health data were obtained from hospital and physician claims records. Negative Binomial regression was used to estimate adjusted rate ratios (RRs) to measure associations between injury and mental health service use.ResultsStatistically significant differences in the rates of mental health service use were observed between the injured and non-injured, for the pre-injury year and every year of the follow-up period. The injured cohort had 6.56 times the rate of post-injury mental health hospitalisations (95% CI 5.87, 7.34) and 2.65 times the rate of post-injury mental health physician claims (95% CI 2.53, 2.77). Adjusting for comorbidities and pre-existing mental health service use reduced the hospitalisations RR to 3.24 (95% CI 2.92, 3.60) and the physician claims RR to 1.53 (95% CI 1.47, 1.59).ConclusionThese findings indicate the presence of pre-existing mental health conditions is a potential confounder when investigating injury as a risk factor for subsequent mental health problems. Collaboration with mental health professionals is important for injury prevention and care, with ongoing mental health support being a clearly indicated service need by injured people and their families. Public health policy relating to injury prevention and control needs to consider mental health strategies at the primary, secondary and tertiary level.

ON MENINGEAL REACTIONS IN SYMPATHETIC OPHTHALMITIS

<h3>Background and Objectives</h3> To assess whether the association among depression, vascular disease, and mortality differs in people with multiple sclerosis (MS) compared with age-, sex-, and general practice–matched controls. <h3>Methods</h3> We conducted a population-based retrospective matched cohort study between January 1, 1987, and September 30, 2018, that included people with MS and matched controls without MS from England, stratified by depression status. We used time-varying Cox proportional hazard regression models to test the association among MS, depression, and time to incident vascular disease and mortality. Analyses were also stratified by sex. <h3>Results</h3> We identified 12,251 people with MS and 72,572 matched controls. At baseline, 21% of people with MS and 9% of controls had depression. Compared with matched controls without depression, people with MS had an increased risk of incident vascular disease regardless of whether they had comorbid depression. The 10-year hazard of all-cause mortality was 1.75-fold greater in controls with depression (95% confidence interval [CI] 1.59–1.91), 3.88-fold greater in people with MS without depression (95% CI 3.66–4.10), and 5.43-fold greater in people with MS and depression (95% CI 4.88–5.96). Overall, the interaction between MS status and depression was synergistic, with 14% of the observed effect attributable to the interaction. Sex-stratified analyses confirmed differences in hazard ratios. <h3>Discussion</h3> Depression is associated with increased risks of incident vascular disease and mortality in people with MS, and the effects of depression and MS on all-cause mortality are synergistic. Further studies should evaluate whether effectively treating depression is associated with a reduced risk of vascular disease and mortality.