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Immunologic Rejection Episodes After Stopping Topical Corticosteroids in DMEK
June 2016
Price et al. evaluated the risk of immunologic rejection episodes when topical corticosteroids are discontinued 1 year after Descemet’s membrane endothelial keratoplasty (DMEK) compared with ongoing once-daily use of topical steroids. They found that patients who discontinued steroids had a higher risk of rejection episodes.
In this prospective longitudinal parallel-group study, 400 eyes from 259 DMEK recipients (aged 23-90) were enrolled 1 year after their transplant. To maximize adherence, the researchers allowed the participants to choose whether to stop or to continue the once-daily topical corticosteroid they were already taking. Steroids were discontinued in 277 eyes (no-steroid group) and continued in 123 eyes (steroid group). In the latter group, 100 eyes continued with fluorometholone 0.1%, 21 with prednisolone 1.0%, and 2 with loteprednol etabonate 0.5%.
Study demographics were well balanced between the steroid and no-steroid groups: 99% of the subjects were white, and 95% of the grafts were performed to treat Fuchs dystrophy. Participants were examined at 1, 3, 6, and 12 months during the second year after their DMEK procedure. Results were evaluated with Kaplan-Meier survival analysis, and the main outcome measure was the incidence of immunologic rejection episodes.
The cumulative incidence of rejection episodes was significantly greater in the no-steroid group (6% vs. 0% in the steroid group; p = .013). Thirteen of 14 rejection episodes (all of which were in the no-steroid group) resolved when topical corticosteroids were resumed. The authors stated that 1 of 277 grafts (0.4%) failed in the nosteroid group, and none failed in the steroid group during the study. Endothelial cell loss between 1 and 2 years was not significantly different between the no-steroid and steroid groups (6.4% ± 12% vs. 5.6% ± 14% percent, respectively; p = .67).
The authors concluded that continuing once-daily use of even a weak topical corticosteroid was protective against rejection episodes during the second year after DMEK. Based on these findings, they prefer to maintain their DMEK patients on a low-strength steroid. They noted, however, that some patients experience steroid-related intraocular pressure elevation and may require antiglaucoma drugs; physicians must balance the risks of different strategies for individual patients.
Genetic and Dietary Factors in Progression of Nuclear Cataracts
June 2016
Yonova-Doing et al. examined the heritability of nuclear cataract and prospectively explored the effect of dietary micronutrients on progression of these cataracts. They found that genetics explained 35% of the variation in progression over 10 years, while environmental factors, including diet, accounted for the balance.
The investigators relied on the TwinsUK prospective cohort study. Cross-sectional nuclear cataract and dietary data were available for 2,054 white female twins from the study, and follow-up cataract measurements were available for 324 of the twins (151 monozygotic and 173 dizygotic). The study’s main outcome measure was nuclear cataract progression, which was assessed through digital Scheimpflug imaging. The mean interval between baseline and follow-up examination was 9.4 years.
Dietary data were obtained from food-frequency questionnaires, and heritability was modeled through a method that estimates additive genetic effects, shared/family environmental effects, and individual environmental effects in twins. Association between nuclear cataract change and micronutrients was investigated via linear and multinomial regression analysis.
The best-fitting model estimated that the heritability of nuclear cataract progression was 35% and that environmental factors explained the remaining 65% of variance. The study evaluated the effect of a large number of micronutrients. Among micronutrients consumed in the diet, only vitamin C and manganese had significant effect. Vitamin C was protective against both nuclear cataract presence at baseline and nuclear cataract progression, while manganese reduced the rate of nuclear cataract at baseline. Combined micronutrient supplements were protective against nuclear cataract at baseline only.
Geographic Variation in Anti-VEGF Injection Rates and Medicare Payments
June 2016
Erie et al. used Medicare claims data to evaluate geographic variation among intravitreal injection rates and anti-VEGF drug payments per injection across the United States. They found that rates of injection varied 7-fold, and payments 6.2-fold, between the highest and lowest states.
This observational cohort study was based on Medicare Provider Utilization and Payment Data from CMS covering all 50 states and Washington, D.C. The data identified 539,660 unique Part B fee-for-service (FFS) beneficiaries for whom approximately 2,199,199 anti-VEGF drug claims were submitted to Medicare in 2013. The number of FFS Medicare beneficiaries who received intravitreal injections and the mean Medicare-allowed drug payment per anti-VEGF injection (aflibercept, bevacizumab, or ranibizumab) were calculated nationally and for each state. Geographic variations were evaluated by using the extremal quotient, coefficient of variation, and systematic component of variance (SCV).
In 2013, the number of FFS Medicare beneficiaries who received intravitreal injections ranged from 4 per 1,000 beneficiaries in Wyoming to 28 per 1,000 in Utah; the national average was 19 per 1,000. In 2013, the mean SCV was 8.5, confirming high nonrandom geographic variation. The mean national Medicare drug payment per anti-VEGF ranged from $242 in South Carolina to $1,509 in Maine; the average was $1,078 per injection. Nationally, 94% of injections were office based, and 6% were facility based.
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Ophthalmology summaries are written by Marianne Doran and edited by Susan M. MacDonald, MD.
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