Severe Mental Illness Ups Risk of Death After Infection

BRIEF COMMUNICATION

Severe mental illness-including schizophrenia and bipolar disorder-is associated with a dramatic increase in premature mortality.¹ This includes mortality from potentially preventable infectious diseases, such as pneumonia and influenza.² However, previous studies of infectious disease mortality do not permit inferences regarding whether persons with severe mental illness are more susceptible to infections, more likely to die following an infection, or both.

Ribe and colleagues³ investigated relative and absolute risks of death within 30 days after hospitalization for infection among people with severe mental illness in a large, population-based cohort. Using nationwide registries in Denmark, the authors identified a cohort of all persons (n = 806,835) age 15 and older hospitalized for a first-time infection between 1995 and 2011.

In this cohort, 11,343 people had a history of severe mental illness, defined as schizophrenia (n = 7388) or bipolar disorder (n = 3955). The authors performed a series of survival analyses of mortality outcomes after admission for any infection, controlling for effects of age, sex, education, substance abuse, and clinical comorbidity (diabetes, cardiovascular disease, and Charlson Comorbidity Index score).

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Within 30 days after admission for any infection (all causes), 59,735 persons died, including 9.3% of persons with severe mental illness and 7.4% of those without such a history. Persons with severe mental illness had a 52% increase in all-cause mortality (mortality rate ratio = 1.52; 95% confidence interval [CI], 1.43-1.61).

Mortality rate ratios were increased for all infections, ranging from 1.27 for sepsis to 2.61 for CNS infections. Mortality rate ratios were significantly higher for schizophrenia (1.71; 95% CI, 1.58-1.85) than for bipolar disorder (1.27; 95% CI, 1.15-1.40). Mortality decreased with age as well as-surprisingly-clinical comorbidity but was not affected by sex or substance use.

The authors found a high mortality rate for hospitalization after infection in persons with severe mental illness. Depending on age, 1.7 to 2.9 more deaths per 100 persons within 30 days after admission for infection were observed in persons with severe mental illness than in those without such a history. These findings complement and extend previous studies that have found increased mortality within 1 year of psychiatric inpatient care in persons with schizophrenia or bipolar disorder.⁴

An important limitation of the study was that clinical data were available only for persons who received hospital care for infection, not for those with (presumably less severe) infections treated in primary care settings. Thus, the findings cannot be generalized to all infections.

The bottom line
Mortality is markedly elevated among persons with severe mental illness after hospitalization for infection. Targeted interventions-such as pneumonia and influenza vaccinations and smoking cessation programs-may reduce the burden of premature mortality among these patients.

Disclosures:

Dr Miller is Associate Professor in the Department of Psychiatry at Georgia Regents University in Augusta, GA, and Schizophrenia Section Editor for Psychiatric Times. He reports no conflicts of interest concerning the subject matter of this article.

References:

1. Miller BJ, Paschall CB, Svendsen DP. Mortality and medical comorbidity among patients with serious mental illness. Psychiatr Serv. 2006;57:1482-1487.

2. Brown S, Kim M, Mitchell C, et al. Twenty-five year mortality of a community cohort with schizophrenia. Br J Psychiatry. 2010;196:116-121.

3. Ribe AR, Vestergaard M, Katon W, et al. Thirty-day mortality after infection among persons with severe mental illness: a population-based cohort study in Denmark. Am J Psychiatry. 2015;172:776-783.

4. Hoang U, Stewart R, Goldacre MJ. Mortality after hospital discharge for people with schizophrenia or bipolar disorder: retrospective study of linked English hospital episode statistics, 1999-2006. BMJ. 2011;343:d5422.