Risk factors of mortality in older patients with dementia in psychiatric care

Objective: To examine the mortality risk, and its risk factors, of older patients with dementia in psychiatric care. Methods: We constructed a cohort of dementia patients through data linkage of four Dutch registers: the Psychiatric Case Register Middle Netherlands (PCR-MN), the hospital discharge register, the population register, and the national cause of death register. All dementia patients in PCR-MN aged between 60 and 100 years between 1 January 2000 and 31 December 2010 were included. Risk factors of mortality were investigated using Cox proportional hazard regression models with adjustment for age, sex, setting of care, nationality, marital status, dementia type, and psychiatric and somatic comorbidities. Results: In total, 4297 patients were included with a median age of 80 years. The 1-year, 3-year, and 5-year mortality were 16.4%, 44.4%, and 63.5%, respectively. Determinants that increased the 1-year mortality were: male sex (adjusted hazard ratio [HR]: 1.49; 95% confidence interval [95% CI], 1.26-1.76), higher age (HR 1.08; 95% CI, 1.07-1.09), inpatient psychiatric care (HR 1.52; 95% CI, 1.19-1.93), more somatic comorbidities (HR 1.67; 95% CI, 1.49-1.87), and cardiovascular disease separately (HR 1.54; 95% CI, 1.30-1.82). Results for 3-year and 5-year mortality were comparable. Living together/married increased the 3- and 5-year mortality, and Dutch nationality increased the 5-year mortality. There were no differences in mortality with different types of psychiatric comorbidity. Conclusion: Mortality of dementia patients in psychiatric care was high, much higher than mortality in the general older population. The results of this study should raise awareness about their unfavourable prognosis, particularly older patients, men, inpatients, and patients with more somatic comorbidity.