The Progression of Serious Mental Disorders to Mortality in Primary Care
Abstract
Serious mental disorders (schizophrenia, bipolar disorder and major depressive disorder (MDD)) have been associated with an excess risk of mortality. However, most datasets used to study these associations have been limited by small sample sizes, use of specialized clinical samples, and few covariates recorded, thereby impeding proper assessments of mortality risks. Electronic medical records databases such as The Health Improvement Network (THIN) directly address these limitations by offering a large primary care population for study, with inclusion of numerous clinically-relevant covariate data over a long follow-up period. To date, THIN has not been used to study mortality in serious mental illness. As such, this thesis had the following objectives: i) estimate annual prevalence of serious mental illness; ii) determine the covariate-adjusted and unadjusted risk of all-cause mortality in serious mental illness and iii) demonstrate the feasibility of using THIN to study the excess mortality associated with serious mental illness. THIN was used to define schizophrenia, bipolar disorder and MDD cohorts between the years of 1986-2012, where annual prevalence estimates in 2012 were 0.23%, 0.26% and 9.49% respectively. Survival analyses adjusted for important covariates revealed that in the schizophrenia cohort (n=6,056), the risk of all-cause mortality was more than double (HR=2.36, 95%CI: 1.83 – 3.04) the risk in the referent cohort (n=6,137,760). Similarly, patients with bipolar disorder (n=9,425) were found to have twice the risk of all-cause mortality (HR=2.00, 95%CI: 1.70-2.34) compared to the referent cohort (n=6,131,373). Patients with MDD (n=405,866) were also found to have a significantly greater risk of all-cause mortality (HR=1.28, 95%CI: 1.21-1.36) compared to the referent cohort (n=5,337,098). Annual prevalence estimates for schizophrenia and MDD were similar to previous reports, but estimates were lower for bipolar disorder, possibly due to issues in correctly identifying these patients in primary care. This study was the first to confirm the excess mortality associated with serious mental disorders using THIN, highlighting that studying mortality among patients with serious mental illness is feasible in THIN. As such, the work presented in this thesis can pave the way for future research using THIN to improve the health of patients with serious mental disorders.
Description
Keywords
Epidemiology, Mental Health
Citation
Vallerand, I. (2016). The Progression of Serious Mental Disorders to Mortality in Primary Care (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/28283