Objective: Single physical comorbidities have been associated with the premature mortality in people with schizophrenia-spectrum disorders (SSD). We investigated the association of physical multimorbidity (≥two physical health conditions) with mortality in people with SSD.
Methods: A retrospective cohort study between 2013 and 2017. All people with a diagnosis of SSD (ICD-10: F20-F29), who had contact with secondary mental healthcare within South London during 2011-2012 were included. A novel semantic search system captured conditions from electronic mental health records, and all-cause mortality were retrieved. Hazard ratios (HRs) and population attributable fractions (PAFs) were calculated for associations between physical multimorbidity and all-cause mortality.
Results: Among the 9775 people with SSD (mean (SD) age, 45.9 (15.4); males, 59.3%), 6262 (64%) had physical multimorbidity, and 880 (9%) died during the 5-year follow-up. The top three physical multimorbidity combinations with highest mortality were cardiovascular-respiratory (HR: 2.23; 95% CI, 1.49-3.32), respiratory-skin (HR: 2.06; 95% CI, 1.31-3.24), and respiratory-digestive (HR: 1.88; 95% CI, 1.14-3.11), when adjusted for age, gender, and all other physical disease systems. Combinations of physical diseases with highest PAFs were cardiovascular-respiratory (PAF: 35.7%), neurologic-respiratory (PAF: 32.7%), as well as respiratory-skin (PAF: 29.8%).
Conclusions: Approximately 2/3 of patients with SSD had physical multimorbidity and the risk of mortality in these patients was further increased compared to those with none or single physical conditions. These findings suggest that in order to reduce the physical health burden and subsequent mortality in people with SSD, proactive coordinated prevention and management efforts are required and should extend beyond the current focus on single physical comorbidities.
Keywords: Comorbidity; Mortality; Schizophrenia; Severe mental illness; Somatic.
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