The effect of comorbid depression on the use of unscheduled hospital care by people with a long term condition: A retrospective observational study.

Background: The prevalence of long-term conditions (LTCs) and multiple-morbidity is increasing. Depression prevalence increases with the number of LTCs. Self-management of LTCs improves outcomes, but depression impacts on self-management. Unscheduled hospital care may be a proxy for failure of planned care to support successful self-management.

Methods: Retrospective observational study based on routine NHS datasets covering 19 LTCs. Prevalence of LTCs and depression was identified in all primary care registered adults in one English city (n = 469,368). Chi squared was used for hypothesis testing, and logistic regression to determine the influence of depression and LTC(s) on the use of unscheduled hospital care.

Results: At least one LTC was identified in 220,010 (46.9%) adults; 75,107 (16.0%) had depression; and 38,232 (8.1%) had LTC plus comorbid depression. A significantly greater proportion of individuals with LTC and comorbid depression had ≥ 1 unscheduled event over 12 months (31.5%) compared to individuals with LTC(s) only (24.0%), X(1) = 883.860, p < .001. The logistic regression model explained 4.4% of the variation in unscheduled care use. Individuals with depression plus ≥ 1 LTC were 1.59 times more likely to use unscheduled hospital care than individuals with LTC only (p < .001), after controlling for deprivation, age and number of LTCs.

Limitations: Cross-sectional data precluded identification of the direction of influence between LTCs and depression. Only 19 major LTCs were studied, so overall LTC prevalence will be under-represented, and other significant predictors may be omitted.

Conclusion: In people with a LTC, comorbidity with depression increases use of unscheduled hospital care.