Longitudinal study of depression and health services use among elderly primary care patients

Abstract

Objective: To describe the prevalence and 9-month incidence of depressive symptoms among a cohort of elderly primary care patients and to determine whether different patterns of depression are associated with different patterns of health services use.

Design: Prospective study of depressive symptoms as measured by the Center for Epidemiologic Studies Depression (CES-D) scale and identification of patients' outpatient health services use through an electronic medical record system.

Setting: An academic primary care group practice at an urban ambulatory care clinic.

Patients/participants: 1711 patients aged 60 and older who completed the CES-D at baseline and 9 months later; 935 of these patients also completed the CES-D at 6 months.

Measurement and main results: The prevalence of significant symptoms of depression (CES-D > or = 16) was 17.1% at baseline and 18.8% at 9 months; 26.8% of patients exceeded the threshold on the CES-D either at baseline or 9 months, and the 9-month incidence was 11.7%. Among the patients re-interviewed at both 6 and 9 months, the 6-month incidence was 12%, and the incidence between the 6- and 9-month assessments was 10%. Of the 292 patients with depression at baseline, 140 (47.6%) remained depressed at the 9-month follow-up. Baseline and 6-month CES-D score, in addition to perceived health at 6 months, explained 45% of the variance in the 9-month CES-D score. Patients above the threshold on the CES-D at any time were more likely to rate their health as fair or poor (69.8% vs 43.7%) and more likely to have an emergency room visit (40.4% vs 29.4%). These patients also had 38% more outpatient visits (7.7 vs 5.6) and 61% higher total outpatient charges ($1209 vs $751) than patients who never exceeded the CES-D threshold over the 9-month window (all P values < 0.01).

Conclusions: Depressive symptoms were frequent and often persistent in this patient population. We identified patterns of oscillating severity of symptoms within individuals but relatively stable incidence and prevalence rates over a 9-month period. Patients who exceeded the threshold on the CES-D at any time during the study had significantly greater health services use and poorer perceived health.