Longitudinal factors associated with mortality in older patients with mood disorders

Background: To clarify the longitudinal risk factors for mortality in older people with bipolar disorder (BD) and major depressive disorder (MDD). Methods: This study is a national cohort study of older patients with mood disorders. Patients were identified from Taiwan's National Health Insurance Research Database and followed from 2008 to 2011. We determined the mortality rates and standardized mortality ratios (SMRs) in this study population. Survival analyses were conducted to examine factors and healthcare utilization patterns associated with mortality during the 3-year follow-up period. Results: 26,570 patients aged >= 65 years and diagnosed with and treated for BD or MDD in 2008 were enrolled (5,854 and 20,716 with BD and MDD, respectively). Within the 3-year follow-up period, 15.24% (n=4048) of the enrolled patients died, including 1003 (17.13%) in the BD and 3045 (14.70%) in the MDD groups. The SMRs for BD and MDD were 1.65 (1.56-1.76), and 1.26 (1.21-1.32), respectively. Among the examined comorbidities, dementia, diabetes mellitus and renal diseases each constituted an elevated relative mortality risk. By contrast, hypertension and hyperlipidemia were associated with a lower risk of mortality. Limitation: In Taiwan's National Health Insurance program, specific medications are prescribed for specific diagnoses and confounding by indication should be kept in mind. Conclusion: Older patients with mood disorders had a relatively high mortality risk over the 3-year follow-up period. Early detection, risk prevention, and better management of comorbid physical and mental disorders can improve the health outcomes of older patients with BD and MDD.