Subjective memory complaints and future depression in primary care patients: A four-year follow-up study

Objective: To investigate the predictive value of subjective memory complaints (SMCs) for having a hospital-based diagnosis of a single depressive episode over a four-year follow-up period. Methods: A prospective register-based cohort study in general practice. All 17 practices in Inner city Copenhagen participated in the study. They had 40,865 registered patients, 2934 aged 65 years or older. Information on SMCs and socio-demographics was collected during two months at enrolment in primary care. Diagnoses of single depressive episodes were retrieved from the Danish Psychiatric Central Research Register. Cox proportional hazard regression models were used to examine risk factors for a hospital-based diagnosis of a single depressive episode. Results: 758 patients aged 65 years or older consulted their GP in October and November 2002. According to our definition, 177 (23%) had SMCs at enrolment, 12 (6.9%) of whom received a diagnosis of a single depressive episode within the follow-up period. In three multivariate models, SMCs were significantly associated with single depressive episodes. In the fully controlled model SMCs had a hazard ratio (HR) of 2.59 for receiving a subsequent depression diagnosis. Conclusions: In an older general practice population, SMCs are associated with increased risk of receiving a hospital-based diagnosis of a single depressive episode.