Incidence and prevalence of coexistent retinal diseases and cognitive impairment or dementia: A systematic review

AbstractBackgroundAs chronic and progressive age‐related diseases, there are commonalities between age‐related macular degeneration (AMD), glaucoma, and diabetic retinopathy (DR), and cognitive impairment (CI) and dementia. We undertook a systematic review to quantify such associations.MethodMEDLINE, EMBASE, PsycINFO and CINAHL were searched (from inception to June 2020) for observational studies reporting incidence or prevalence of AMD, glaucoma or DR in people with CI or dementia, and CI or dementia among people with AMD, glaucoma or DR. A 9‐item quality assessment tool was used to categorize studies as having low, moderate or high risk of bias. Rates of comorbid disease were extracted and presented in forest plots. Prospero registration [CRD42020189484].ResultOf 6,803 abstracts reviewed, 76 were considered for full‐text analysis, of which 47 were included for syntheses. There were 27 and 20 assessed as having low and moderate risk of bias, respectively.Incidence of dementia in people with age‐related retinal diseases ranged from 9.5 to 20 (AMD), from 1.1 to 11.6 (glaucoma) and was 32.9 (DR) per 1000 person‐years, respectively (Figure 1). There were no reports on the incidence of CI in AMD, glaucoma or DR, nor of retinal diseases in CI or dementia.There were two studies reporting prevalence of AMD or glaucoma in people with CI (Figure 2). Prevalence of DR in those with CI ranged from 11.4% to 70.1%. Prevalence of AMD, glaucoma and DR among people with dementia ranged from 1.4% to 52.6%, from 0.2% to 25.9% and from 11 to 20%, respectively.Prevalence of CI in people with AMD, glaucoma and DR ranged from 8.4% to 52.4%, from 2.8% to 90.2% and from 3.9% to 45.2%, respectively (Figure 3). Prevalence of dementia in people with AMD, glaucoma and DR ranged from 9.9% to 62.6%, 2.5% to 3% and 0.8% to 12.5%, respectively.ConclusionThere are wide ranging estimates of incidence and prevalence of retinal diseases in relation to CI/dementia. Further research is required to better understand the reasons for such variations.