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Association of Obesity With Diabetic Retinopathy
March 2016
The association between obesity and diabetic retinopathy (DR) is equivocal, perhaps because of the interrelationship between generalized and abdominal obesity, which may have a confounding effect. Man et al. investigated the associations of generalized obesity (assessed by body mass index [BMI]) and abdominal obesity (assessed by waist to hip ratio [WHR]) with DR in a clinical sample of Asian patients.
This cross-sectional clinic-based study, conducted at the Singapore National Eye Centre, included 420 patients (mean age, 57.8 years; 67.9% men) with type 2 diabetes. The presence and severity of DR were graded from retinal images into the following groups: none, mild-moderate, and severe DR. The associations of BMI and WHR with DR were assessed using multinomial logistic regression models adjusting for age, sex, traditional risk factors, and mutually for BMI and WHR.
Among these patients, the median (interquartile range) for BMI and WHR were 25.7 (5.7) and 0.94 (0.08), respectively. In multivariable models, BMI was inversely associated with mild-moderate and severe DR (odds ratio [OR], 0.90 and 0.92, respectively, per 1-unit increase), while WHR was positively associated with mild-moderate and severe DR (OR, 3.49 and 2.68, respectively, per 0.1-unit increase) in women. No sex-specific associations were found between BMI and DR.
The researchers concluded that in this group of patients, a higher BMI appeared to confer a protective effect against DR, while higher WHR was associated with the presence and severity of DR in women. The results may inform future clinical trials to determine whether WHR is a more clinically relevant risk marker than BMI for individuals with type 2 diabetes.
Survey of Patients on Marijuana Use to Treat Glaucoma
March 2016
Little is known regarding glaucoma patients’ perceptions about using marijuana for glaucoma and their intentions to try this therapeutic alternative. Belyea et al. conducted a cross-sectional survey among glaucoma patients and suspects to identify factors that might affect intentions to use marijuana for treatment.
This study was conducted at an academic-based glaucoma clinic in Washington, D.C. (where medical marijuana use is legal), between Feb. 1 and July 31, 2013. Of the 334 patients invited to participate, 204 completed a self-administered survey assessing demographics, perceived severity of glaucoma, prior knowledge about marijuana use in glaucoma, past marijuana use, perceptions on marijuana use (including legality, effectiveness, and safety), satisfaction with current glaucoma management, relevance of treatment costs, and intentions to use marijuana for glaucoma. About half the participants were women (51.0%), and 40.2% were white.
The main outcome was patients’ intentions to use marijuana for glaucoma; overall, the intentions were generally modest (mean score, 2.36 on a scale of 1-5). Multiple linear regression analysis was conducted to identify factors associated with patients’ intentions to use marijuana for glaucoma. This analysis indicated that perceptions of legality of marijuana use (β coefficient, 0.378), false beliefs regarding marijuana (β, 0.323), satisfaction with current glaucoma care (β, –0.222), and relevance of marijuana and glaucoma treatment costs (β, 0.127) were significantly associated with intentions to use marijuana for glaucoma after controlling for demographic variables, disease severity, and previous marijuana use.
The American Glaucoma Society has recommended against the use of marijuana in the treatment of glaucoma because of its short duration of action, its documented adverse effects, and the lack of scientific evidence that its use could alter the course of glaucoma. Given the legality and growing public acceptance of the use of medical marijuana, this study’s findings suggest a need for more education on this topic so that ophthalmologists can help protect their patients by counteracting false perceptions on the therapeutic value of marijuana in treating glaucoma.
Geographic Variation in Cataract Surgery
March 2016
Kauh et al. sought to assess the extent of geographic variation in patient age at initial cataract surgery and the age-standardized cataract surgery rate in a large group of insured U.S. patients. They found considerable variation in these parameters in different communities.
The researchers undertook a retrospective cross-sectional study of 1,050,815 beneficiaries older than 40 years of age with cataracts who were enrolled in a nationwide managed-care network during the period from 2001 to 2011. The main outcomes and measures were median age at initial cataract extraction, age-standardized cataract surgery rate, and time from initial diagnosis to first surgery for patients with cataracts in 306 communities.
A total of 243,104 patients with cataracts (23.1%) underwent 1 or more surgical procedures. Communities with the youngest and oldest patients at initial surgery showed an age difference of nearly 20 years (59.9-60.1 years in Lansing, Mich., and Aurora, Ill., vs. 77.0-79.6 years in Marquette, Mich., Rochester, N.Y., and Binghamton, N.Y.). The highest age-standardized cataract surgery rate (37.3% in Lake Charles, La.) was 5-fold higher than the lowest (7.5% in Honolulu). The median time from initial cataract diagnosis to date of first surgery ranged from 17 days (Victoria, Texas) to 367 days (Yakima, Wash.).
Multivariable regression modeling generated hazard ratios (HRs) with 95% CIs identifying factors associated with patients’ likelihood of undergoing cataract surgery. Compared with white patients, black patients had a 15% decreased hazard of surgery (HR, 0.85), while Latino patients (HR, 1.08) and Asian patients (HR, 1.09) had an increased hazard. For every 1-degree higher latitude, the hazard of surgery decreased by 1% (HR, 0.99). For every additional optometrist per 100,000 enrollees in a community, the hazard of surgery increased 0.1% (HR, 1.001).
These data indicate that in recent years, patient age at first cataract surgery and the age-standardized surgery rate have varied considerably among some U.S. communities; these findings contrast with studies in the 1980s, which showed little geographic variation. The authors recommend that future studies should explore the underlying causes for such variation and its effect on patient outcomes.
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JAMA Ophthalmology summaries are based on authors’ abstracts, as edited by senior editor(s).
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