People with mental health disorders are at higher risk for premature mortality based on both morality rate ratios and life years lost, according to the results of a comprehensive analysis published in The Lancet.
Researchers at the National Centre for Register-based Research, Aarhus University in Denmark reviewed data collected for 7,369,926 people aged 95 years and under who lived in Denmark between January 1995 and December 2015. High-quality national registers provided information about mental disorders and the dates and causes of death, categorizing them as natural (eg, diseases and medical conditions) or external (eg, suicide, homicide, and accidents). For all-cause mortality and for each specific cause of death, researchers estimated mortality rate ratios using Poisson regression models. They also determined excess life years lost, a measurement that accounts for the age of disorder onset and allows for the quantification of a reduction in life expectancy.
For those with a diagnosis of a mental disorder (n=762,419; 10.3% of total), mortality rates were higher than for the general population (28.70 deaths vs 12.95 deaths per 1000 person-years). The mortality rate ratio for all people diagnosed with a mental disorder was 2.53, and men and women had largely similar rates. Substance use disorders accounted for the highest ratio (3.91), followed by intellectual disabilities (3.50) and organic disorders (2.94).
Mortality rates for all causes of death were also higher for individuals with a mental disorder, with ratios ranging from 11.82 for suicide to 1.40 for neoplasms. The association between any mental disorder and suicide was higher for females than for males (mortality rate ratio 17.52 vs 10.52). Despite the higher association between death by suicide and other external causes in individuals with mental disorders, researchers noted that most premature death in this group was attributable to natural causes.
Based on life years lost, both males and females with a mental disorder had a shorter average life expectancy than those without a diagnosis, dying 10.06 and 7.06 years sooner, respectively. Substance use disorders in males were associated with the most life years lost (14.84 years). One novel finding of the study was that while males with mental disorders experienced a higher mortality rate related to neoplasms, they lost fewer years of life related to neoplasms, largely because they had even higher rates of dying from non-cancer causes.
Data were gathered from diagnosed patients who received care in a hospital, outpatient, or emergent setting, and did not capture individuals seen by a general practitioner or who received no care for a mental health disorder. Furthermore, the researchers noted that they may have slightly underestimated life years lost given overestimation of age of mental disorder onset.
“Our findings highlight the need for coordinated care of general medical conditions in those with mental disorders,” the researchers wrote. “Additionally, we hope that these estimates can provide a solid foundation for future research related to improving the life expectancy of people with mental disorders.”
Plana-Ripoll O, Pedersen CB, Agerbo E, et al. A comprehensive analysis of mortality-related health metrics associated with mental disorders: a nationwide, register-based cohort study. Lancet. 2019;394(10211):1827-1835.