Premature mortality among adults with schizophrenia in the United States

Abstract

IMPORTANCE Although adults with schizophrenia have a significantly increased risk of premature mortality, sample size limitations of previous research have hindered the identification of the underlying causes. OBJECTIVE To describe overall and cause-specific mortality rates and standardized mortality ratios (SMRs) for adults with schizophrenia compared with the US general population. DESIGN, SETTING, AND PARTICIPANTS We identified a national retrospective longitudinal cohort of patients with schizophrenia 20 to 64 years old in the Medicaid program (January 1, 2001, to December 31, 2007). The cohort included 1 138 853 individuals, 4 807 121 years of follow-up, and 74 003 deaths, of which 65 553 had a known cause. MAIN OUTCOMES AND MEASURES Mortality ratios for the schizophrenia cohort standardized to the general population with respect to age, sex, race/ethnicity, and geographic region were estimated for all-cause and cause-specific mortality. Mortality rates per 100 000 person-years and the mean years of potential life lost per death were also determined. Death record information was obtained from the National Death Index. RESULTS Adults with schizophrenia were more than 3.5 times (all-cause SMR, 3.7; 95%CI, 3.7-3.7) as likely to die in the follow-up period as were adults in the general population. Cardiovascular disease had the highest mortality rate (403.2 per 100 000 person-years) and an SMR of 3.6 (95%CI, 3.5-3.6). Among 6 selected cancers, lung cancer had the highest mortality rate (74.8 per 100 000 person-years) and an SMR of 2.4 (95%CI, 2.4-2.5). Particularly elevated SMRs were observed for chronic obstructive pulmonary disease (9.9; 95%CI, 9.6-10.2) and influenza and pneumonia (7.0; 95%CI, 6.7-7.4). Accidental deaths (119.7 per 100 000 person-years) accounted for more than twice as many deaths as suicide (52.0 per 100 000 person-years). Nonsuicidal substance-induced death, mostly from alcohol or other drugs, was also a leading cause of death (95.2 per 100 000 person-years). CONCLUSIONS AND RELEVANCE In a US national cohort of adults with schizophrenia, excess deaths from cardiovascular and respiratory diseases implicate modifiable cardiovascular risk factors, including especially tobacco use. Excess deaths directly attributable to alcohol or other drugs highlight threats posed by substance abuse. More aggressive identification and management of cardiovascular risk factors, as well as reducing tobacco use and substance abuse, should be leading priorities in the medical care of adults with schizophrenia.