Prognosis of depression in elderly community and primary care populations: a systematic review and meta-analysis.

OBJECTIVE: The purpose of this study was to determine the prognosis of depression in elderly community and primary care populations.
METHOD: MEDLINE and PsycINFO were searched for potentially relevant articles published from January 1981 to November 1996 and from January 1984 to November 1996, respectively. The bibliographies of relevant articles were searched for additional references. Twelve studies met the following five inclusion criteria: original research, published in English or French, study population of community residents or primary care patients, subjects' mean age 60 years and over, and reported affective state as an outcome. The validity of the studies was assessed according to the criteria for prognostic studies described by the Evidence-Based Medicine Working Group. Information about the population, proportion of depressed subjects detected and treated by primary care physicians, length of follow-up, outcomes, and prognostic factors was systematically abstracted from each report.
RESULTS: All of the studies had some methodologic limitations. A meta-analysis of outcomes at 24 months estimated that 33% of subjects were well, 33% were depressed, and 21% had died. There was statistically significant heterogeneity in the outcomes across studies. The length of follow-up and lower age limit for enrollment explained part of the heterogeneity for the percent well but not for the other outcomes. Physical illness, disability, cognitive impairment, and more severe depression were associated with worse outcomes but inconsistently so.
CONCLUSIONS: Depression in elderly community and primary care populations has a poor prognosis, is perhaps chronic or relapsing or both, and is probably undertreated. Despite the methodologic limitations of the studies and this meta-analysis, these findings seem to support efforts to develop detection and treatment programs for depression in these populations.