12 Year Trajectories of Depressive Symptoms in Community-Dwelling Older Adults and the Subsequent Risk of Death over 13 Years

Background Populations of depressed persons are typically comprised of individuals with different courses of depression and thus might carry different risks of death. This study aimed to identify different trajectories of depressive symptoms in community-dwelling older adults and study the risk of death across these trajectories.
Methods In the population-based Rotterdam Study, depressive symptoms (Center for Epidemiological Studies-Depression scale) at three examination rounds (1993-2004) from 3,325 dementia-free participants (mean age 64.6 ± 6.1 years) were used to identify depression trajectories by latent-class trajectory modeling. Mortality rates by trajectory were calculated over a subsequent 13 year period (2002-2015), that is using 23 years of follow-up data.
Results Five trajectories of depressive symptoms characterized by low (73.4%), decreasing (11.1%), remitting (5.1%), increasing (7.7%), and high (2.7%) depressive symptoms were identified. Compared with persons in the low symptoms trajectory, persons with a trajectory of increasing depressive symptoms (hazard ratio [HR]: 1.21 [95% CI = 1.02, 1.44]) had a higher risk of death, but not those with remitting depressive symptoms, HR: 1.06 (95% CI = 0.85, 1.32). The estimates for the high symptoms trajectory were also suggestive of a higher risk of mortality, HR: 1.20 (95% CI = 0.91, 1.58).
Conclusions Repeated measures of depression can help predict long-term health outcomes in persons with depressive symptoms. Participants with increasing symptoms over time had a higher risk of death than those with low or no depressive symptoms. Transient high depressive symptoms that remitted were not associated with a higher risk compared with those with no symptoms. Our results open avenues for etiological and prognostic research to focus upon risk factors' key to a particular trajectory.