Increased risk of depressive disorder following a diagnosis of neovascular age-related macular degeneration.

Abstract

Age-related macular degeneration (AMD), a leading cause of vision loss among elderly population, has been suggested to be a major risk factor for depression (Casten & Rovner 2013). The prevalence of depression among patients with AMD was estimated ranging from 32.5% to 44.4% (Jivraj et al. 2013). It is suggested that the fear of future worsening of their vision faced by patients with AMD could be a source of great psychological distress. In turn, depression can also exacerbate the impairment in vision function of patients with AMD. However, unequivocal conclusions could not be drawn due to small sample size and selection bias in previous studies. In addition, the majority of previous studies that concurrently investigated AMD and depression were cross-sectional in design. We tried to tackle this important issue by a retrospective cohort analysis sourced from a nationwide population-based database in Taiwan. We identified 1538 subjects older than 40 years with neovascular AMD (ICD-9-CM codes 362.42, 362.43, 362.52, or 362.53) and 4614 matched subjects without AMD between 2005 and 2008 from the Taiwan Longitudinal Health Insurance Database 2000. Subjects with a history of major psychiatric disorders, depressive disorders or substance-related disorders (ICD-9-CM codes 290–299 or 303–305) prior to their recruitment were excluded. Within one-year follow-up period, 66 subjects had received diagnosed with depressive disorder by certificated psychiatrists. Incidence rates of depressive disorder were 18.86 (95% CI: 12.87–26.73) per 1000 person-years for the study cohort and 8.02 (95% CI: 7.73–10.93) per 1000 person-years for the comparison cohort. The mean ± SD days between index date and the first diagnosis of depressive disorder were 175 ± 106 days for subjects with neovascular AMD and 164 ± 182 days for those without it (p = 0.491). Further stratified Cox proportional analysis showed that compared with subjects without neovascular AMD, the hazard ratio of depressive disorder during the one-year follow-up period was 2.37 (95% CI: 1.45–3.88, p < 0.001) for subjects with neovascular AMD after adjusting for patients' monthly income, geographical location and urbanization level (Table 1). This population-based study demonstrated a close relationship between neovascular AMD and subsequent depressive disorder in an Asian population. The literature review by Casten & Rovner (2013) suggested that the proposed mechanisms linking AMD to depression included impaired function and loss of the ability to pursue valued activities. The development of depression might aggravate the physical disability associated with AMD and could force patients to disengage from enjoyable activities. Indeed, depression may contribute more to disability than to visual impairment in patients with AMD (Banerjee et al. 2008). However, the proposed mechanisms could not be verified in current study due to lacking of personal ophthalmological data such as the severity of visual impairment. Thus, other factors contributing to this association need to be taken into consideration for effective intervention programs in the future. The use of a longitudinal, population-based data set with an ample sample size herein can help to clarify this important issue. Nevertheless, the true incidence of depressive disorder could be underestimated for depressive symptoms often being overlooked and untreated. Besides, referral bias should be of concern that subjects with AMD were more likely to be diagnosed with depressive disorder purely based on their increased exposure to the medical community. Further studies should seek to clarify the underlying mechanisms for this link. It is suggested that ophthalmologists need to efficiently screen for depression and appropriately refer depressed patients with AMD for treatment.