Physical comorbidity including type-2 diabetes mellitus as a predictor of mortality in bipolar patients: a naturalistic 12-year follow-up in general hospital admissons

Introduction - Physical comorbidity is highly prevalent in bipolar disorder (BD). Consequently, we investigated whether physical comorbidity and its relevance on general hospital mortality differs between patients with- and without BD in a 12-year follow-up in general hospital admissions. Methods - During 1 January 2000 and 30 June 2012, 621 bipolar patients were admitted to three General Manchester Hospitals. All comorbidities were compared with those of a prevalence ≥ 1% in 6210 age- and gender matched hospital controls. Comorbidities that were predictors of general hospital mortality were identified using logistic regression analyses. Results –Type-2 diabetes mellitus (T2DM) was increased in the bipolar population compared to the control population. Additionally, T2DM was significantly elevated in the 60 bipolar patients that died during the study period (25.0%) compared to those 541 bipolar patients that survived the study period (11.2%), and deceased bipolar patients had significantly more suffered T2DM than deceased control subjects (25.0% versus 14.6%). However, T2DM did not significantly contribute to explain the outcome hospital death in the control population. Further predictors of inpatient mortality in BD were hypertension, chronic obstructive pulmonary disease, pneumonia, bronchitis, and ischemic stroke. There were no differences in their impact on hospital death compared to the same comorbidities in hospital controls except T2DM. Conclusion - T2DM represents a major predictor of general hospital mortality in BD. The study gives support for an aggressive multidisciplinary approach to identify and treat T2DM to prevent diabetic-, respiratory- and vascular complications in all bipolar patients