Role of depressive symptoms and comorbid chronic disease on health-related quality of life among community-dwelling older adults

Objective: This study examined the influence of depressive symptoms on health-related quality of life (HRQOL) among community-dwelling older adults suffering from various categories of chronic comorbidity. Methods: A population-based survey in adults aged 60 years or more was conducted within a random sample of 1085 beneficiaries of the Mexican Institute of Social Security in Mexico City. Depressive symptoms were evaluated with the 15-item Geriatric Depression Scale, and chronic comorbidity was determined with self-reports concerning prior medical diagnoses and the HRQOL Short Form-36 health survey. We carried out a stratified analysis by comorbidity category, evaluating the impact of depressive symptoms on HRQOL through an analysis of variance and modeling the independent association of depression symptoms with HRQOL using multiple linear regression analyses adjusted for comorbidity and other covariables. Results: HRQOL scores were low in the presence of depressive symptoms, while their impact increased when chronic diseases were also present. The group with the poorest HRQOL was older adults suffering from both depressive symptoms and two or more chronic diseases (P<.05). The stratified analysis by comorbidity and multivariate analysis, adjusted for covariables, indicated that depressive symptoms and comorbidity had cumulative negative effects on HRQOL. Conclusion: The HRQOL of older adults deteriorated when depressive symptoms were present and decreased even further with the simultaneous occurrence of chronic illnesses. Identifying depression symptoms-either alone or along with chronic conditions-is crucial for implementation of measures aimed at improving elderly people's HRQOL. (C) 2009 Elsevier Inc. All rights reserved.