Impact of somatic comorbidities on mortality rates and clinical progression of unipolar depression: A 10-year prospective study with depressed inpatients

INTRODUCTION: Somatic comorbidities and unipolar depression (UD) are frequent comorbidities and can lead to some diseases being overlooked, complicating treatment and recovery. Patients with UD die on average more than 10 years younger than those in the overall population. No study has evaluated the association between somatic comorbidities and mortality in the progression of UD using a clinical staging model. We assessed the prevalence of somatic comorbidities in a sample of inpatients with UD at different stages of progression and the mortality rates after a 10-year follow-up, identifying the underlying causes and predictors of mortality. METHODS: Longitudinal study with 151 inpatients with UD, evaluated at hospital admission and 10 years after discharge. The UD progression was assessed using the clinical staging model of UD. The t-test and chi-square test were used to compare the groups' survival and mortality rates. A multivariable Poisson regression model with robust variance estimation was used to evaluate mortality risk and predictors. RESULTS: Of the 151 patients, 28 (19 %) died after 10 years of follow-up. The most frequent underlying cause of death was cardiovascular diseases (32 %). Somatic comorbidities were more prevalent in the residual (67 %) and recurrent (71 %) stages of UD. Age (p = 0.000) and the number of somatic comorbidities (p = 0.000) were predictors of mortality. CONCLUSIONS: The majority of patients exhibited somatic comorbidities, which were more prevalent in the residual and recurrent stages of UD. Somatic diseases, especially cardiovascular diseases, were the leading causes of underlying mortality. Moreover, the number of comorbidities significantly predicted mortality among inpatients with UD.