Relation between depressed mood, somatic comorbidities and health service utilisation in older adults: results from the KORA-Age study

BACKGROUND: prior literature suggests that comorbidity with depression significantly worsens the health state of people with chronic diseases. OBJECTIVE: the present study examines whether depressed mood increased medical care use for patients with a comorbid physical disease. DESIGN, SETTING AND SUBJECTS: the study was a population-based study (KORA-Age), with 3,938 participants aged 64-94. METHODS: we investigated differences in health services use in participants with and without depressed mood (Geriatric Depression Scale). A further adjustment for disease was done and differences were examined with the Mann-Whitney U test. The incidence rate ratios (IRRs) for doctors' appointments or the number of days in hospital were explored with (zero-inflated) negative binomial regression models. RESULTS: there are increased self-neglecting behaviours and medical comorbidities in participants with depressed mood. Depressed mood increased participants' use of medical services (P < 0.0001). Among participants who visited the doctor during the last 3 months, those with depressed mood had more visits than those without depressed mood, irrespective of somatic comorbidities (P < 0.0001 and P < 0.05 for ill and healthy, respectively). Additionally, patients with coexisting depressed mood and physical disease visited the doctor's practice significantly more often. Having depressed mood significantly increases the likelihood for more doctor visits (IRR = 1.5, CI = 1.3-1.7) and longer hospital stays (IRR = 1.9, CI = 1.6-2.3). In participants with somatic comorbidities the risk is even greater (IRR = 1.6, CI = 1.3-2, for the number of doctors visits and IRR = 2, CI = 1.4-2.9, for the number of days in the hospital). CONCLUSIONS: results suggest that patients with depressed mood had increased use of health-care services overall, particularly those with somatic comorbidities.