Depression as a determinant of quality of life in patients with chronic disease: data from Brazil.

Background: Depressive symptoms are associated with impaired quality of life (QOL). However, there are scarce data comparing the magnitude of depression on QOL among persons with different chronic diseases in developing countries. This study aimed to evaluate the impact of depression on QOL in patients with ischemic heart disease (IHD) and end-stage renal disease (ESRD) in hemodialysis.
Methods: Cross-sectional survey conducted in 173 patients: 103 with IHD and 70 in hemodialysis. Depression was diagnosed by the Mini International Neuropsychiatric Interview-5.0 and depressive symptoms measured by Beck Depression Inventory. QOL was assessed through the Short-Form-36 (SF-36) and World Health Organization Quality of Life Instrument-brief (WHOQOL-brief). Multivariate analyses were performed to assess the association between variables and QOL.
Results: Depression prevalence was 14.3% among IHD patients and 9.9% in the hemodialysis group, and depressive symptoms were present in 39 and 36%, respectively. Regardless of the chronic condition, depressed patients presented lower QOL scores than non-depressed ones in all domains, and the most affected were role emotional, mental health and social functioning of SF-36, and psychological domain of WHOQOL-brief. In linear regression analysis, depressive symptoms were predictive for lower QOL in all domains, with the highest standardized beta coefficients (ranging from -0.26 to -0.64).
Conclusion: Depression is an independent factor associated with worse QOL in IHD and ESRD patients. Among the priorities aiming at improving QOL must be evaluation and management of depressive symptoms.