Determinants and consequences of polypharmacy in patients with a depressive disorder in later life

Polypharmacy and late-life depression often congregate in the geriatric population. The primary objective is to identify determinants of polypharmacy in patients with depression, and second to examine polypharmacy in relation to various clinical phenotypes of depression and its course.

A longitudinal observational study using data of the Netherlands Study of Depression in Older persons (NESDO) including 375 patients with depression $$ 60 years and 132 non-depressed comparisons. Linear and logistic regression were used to analyze both polypharmacy (dichotomous: ≥5 medications) and number of prescribed drugs (continuous) in relation to depression, various clinical phenotypes, and depression course.

Polypharmacy was more prevalent among patients with depression (46.9%) versus non-depressed comparisons (19.7%). A lower level of education, lower cognitive functioning, and more chronic diseases were independently associated with polypharmacy. Adjusted for these determinants, polypharmacy was associated with a higher level of motivational problems, anxiety, pain, and an earlier age of onset. A higher number of drugs was associated with a worse course of late-life depression (OR = 1.24 [95% CI: 1.03-1.49], p = 0.022).

Older patients with depression have a huge risk of polypharmacy, in particular among those with an early onset depression. As an independent risk factor for chronic depression, polypharmacy needs to be identified and managed appropriately. Findings suggest that depression moderates polypharmacy through shared risk factors, including motivational problems, anxiety, and pain. The complex interaction with somatic health burden requires physicians to prescribe medications with care.