Multimorbidity (MM) refers to the coexistence of two or more chronic diseases in the same individual; it encompasses medical comorbidity (MC) and psychiatric comorbidity (PC). Hypothesis: MM is prevalent amongst in-patients suffering from affective disorders (AD) and also impacted on length of stay.

To determine the prevalence of MM and its impact on duration of hospitalization in AD admissions.

This cross-sectional study was conducted using secondary data taken from discharge records of 1056 adults admitted for AD to a Quebec-based facility, between 2006 and 2014. Distribution of AD cases: 47% depression, 53% bipolar disorders.

The prevalence rate of MM: 85%. PC was present in 70% of sample whereas MC was present in 62%. The median number of comorbid illnesses was 2.7 for each study subject. The rate of MM was not related to age or gender. Metabolic syndrome (54%), cardiovascular diseases and chronic pain syndrome (17%) were the most prevalent MC in both depressed and bipolar populations. Personality disorder (65%) was highest in the depression population, whereas substance misuse (55%) was the most prevalent PC in the bipolar subjects. A longer length of stay was correlated with MM. However, a logistic regression analysis indicated that duration of hospitalization was only correlated with MC.

The observation that MM is the norm, even in this relatively young population with AD. The results confirmed that MC prolongs hospital stay. These findings advocate strongly for integrated management of psychiatric and physical health problems in clinical practice.

The authors have not supplied their declaration of competing interest.