Abstract
Purpose: :
African-Americans are less likely to undergo cataract surgery than Caucasians of the same age and gender. Visual function and cataract severity do not fully account for the disparity. Our aim was to characterize the extent to which racial differences are explained by different frequencies of mortality and to determine whether ages at which surgeries are performed differ among those who access surgery.
Methods: :
Individuals between 65 and 80 years of age were followed for 8 years in a population-based study (the Salisbury Eye Evaluation project). Cataract severity was assessed from lens photographs. Dates of cataract surgery and mortality were collected prospectively. Participants who had cataract surgery prior to enrollment or visual impairment due to other causes were excluded. Statistical approach: Competing events of age at first-eye surgery and age at death while surgery-free were modeled jointly. To allow for removals from the risk set of surgery due to deaths while surgery-free, a mixture model of two Weibull distributions was used.
Results: :
1862 participants were followed for 8515 person-years; median age at baseline was 72 years and 518(28%) were African-Americans. During follow-up, 309(23%) Caucasians had cataract surgery and 260(19%) died surgery-free; the corresponding numbers for African-Americans were 79(15%) and 127(25%). The model estimated that 52% of Caucasians and 37% of the African-Americans would undergo surgery during their lifetime at a median age of 77 years; those who died before accessing the service (48% Caucasian, 63% African-American) would do so at a median age of 79 and 78 years. Stratified analysis by baseline severity showed more pronounced racial differences in lifetime surgery utilization for the subgroup with severe cataract.
Conclusions: :
Among those with severe cataract at baseline, higher mortality among African-Americans explained racial disparities in cataract surgery utilization. Among those without severe cataract at baseline, there was less disparity in the frequency of cataract surgery but African-Americans were operated at older ages.
Keywords: clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology • cataract • clinical (human) or epidemiologic studies: risk factor assessment