Figure 2 Kaplan-Meier survival curve of time to incidence of mild cognitive impairment (MCI) by recurrence of depressive symptoms (DS)

Results are based on Cox proportional hazards model and log-rank test for trend. Recurrence of DS was based on the number of visits in which the Center for Epidemiologic Studies Depression Scale (CES-D) score was ≥16. The variable was time-dependent so that a person can be without a history of elevated DS in 1 period of time, screening positive once in another, and twice or more in a subsequent period of time, in a cumulative fashion. However, visits with missing CES-D scores were considered as missing for the time-dependent variable. This analysis was based on 86 failures.