Forty-Five-Year Mortality Rate as a Function of the Number and Type of Psychiatric Diagnoses Found in a Large Danish Birth Cohort

Abstract

Psychiatric comorbidities are common among psychiatric patients and typically associated with poorer clinical prognoses. Subjects of a large Danish birth cohort were used to study the relation between mortality and co-occurring psychiatric diagnoses. We searched the Danish Central Psychiatric Research Registry for 8109 birth cohort members aged 45 years. Lifetime psychiatric diagnoses (International Classification of Diseases, Revision 10, group F codes, Mental and Behavioural Disorders, and one Z code) for identified subjects were organized into 14 mutually exclusive diagnostic categories. Mortality rates were examined as a function of number and type of co-occurring diagnoses. Psychiatric outcomes for 1247 subjects were associated with 157 deaths. Early mortality risk in psychiatric patients correlated with the number of diagnostic categories (Wald χ² = 25.0, df = 1, P < 0.001). This global relation was true for anxiety and personality disorders, but not for schizophrenia and substance abuse, which had intrinsically high mortality rates with no comorbidities. Risk of early mortality among psychiatric patients appears to be a function of both the number and the type of psychiatric diagnoses.