Cataracts & Fractures, AREDS2 Update

Cataract Removal Lowers Risk of Hip Fracture

The results of a study published in the August 1st issue of JAMA suggest that individuals shouldn’t necessarily be regarded as ‘too old’ or ‘too ill’ to have cataract extraction.

The study (1), conducted by researchers from the Dept. of Ophthalmology, Warren Alpert Medical School of Brown University, and the Jules Stein Institute at UCLA, found that elderly patients who undergo cataract surgery had a 16% lower risk of hip fracture [adjusted odds ratio of 0.84] within one year after the procedure compared to those with cataract who don’t have the surgery.

Included in the study were over 1.1 million patients 65 years and older with a diagnosis of cataract who represented a 5% random sample of US Medicare Part B beneficiaries. Between 2002 and 2009, about 37% of these patients underwent cataract surgery. The authors adjusted for age, gender, ethnicity, residency, cataract severity, physically limiting conditions and other ocular and systemic diseases, including the Charlson Co-morbidity Index (CCI).

The largest reduction in hip fracture risk was seen among people 80-84 years of age with scores in the highest categories for CCI. Risk reduction was 28% [adjusted OR of 0.72] – the lowest odds of hip fracture among all the age groups.

Study limitations include its retrospective and observational design. The large number of patients included was the study’s greatest strength, providing the statistical power to accurately see differences between the 2 groups.

AREDS2 Reports Baseline Characteristics

The primary purpose of the second AREDS trial, begun in 2006, is to evaluate the efficacy and safety of supplemental lutein plus zeaxanthin and/or the omega-3 fatty acids EPA and DHA in reducing the risk of developing advanced AMD. The study also assesses a reduction in zinc and removing beta-carotene from the original AREDS formulation.

In a first report (2) published in the journal Ophthalmology, AREDS2 investigators inform readers of the baseline characteristics of 4203 participants enrolled at 82 U.S. clinical centers.

The mean age of participants is 74 years, and the majority of them are women (57%) and Caucasian (97%).

Seven percent are current smokers. Participants who were current smokers – or those who had stopped smoking within the year before enrollment – were randomly assigned to study arms that omitted supplemental beta-carotene.

Nineteen percent had cardiovascular disease prior to entering the study, and 44% and 50% are taking cholesterol-lowering statin drugs and aspirin, respectively. The rate of diabetes is more than double among AREDS2 participants (13%) than it was in the AREDS population (6%).

Ocular characteristics include 59% with bilateral large drusen, and 32% with advanced AMD in one eye and mean visual acuity of 20/32 in eyes without advanced AMD.

The AREDS authors also state that AREDS2 study visits are scheduled for completion by December 2012, and that results of the study are likely to be published by the end of 2013.

In a related paper (3), Paul Bernstein MD and colleagues at the Moran Eye Institute of the University of Utah report that the baseline macular pigment optical density in a relatively small group of AREDS2-enrolled subjects was unusually high compared to age-matched controls that did not regularly use lutein/zeaxanthin supplements.

According to the authors, this finding is consistent with the high rate of carotenoid consumption for Utah AREDS2 subjects prior to their enrollment. MPOD is being measured only in this ancillary Utah study, not in all AREDS2 subjects.

References

1. Tseng VL, et al. Risk of fractures following cataract surgery in Medicare beneficiaries JAMA 308:493-501, 2012.
2. The AREDS2 Research Writing Group. The Age-Related Eye Disease Study 2 (AREDS2): Study Design and Baseline Characteristics. AREDS2 Report No 1. Ophthalmol. July 26, 2012. [Epub ahead of print]
3. Bernstein P, et al. Macular pigment imaging in AREDS2 participants. IOVS Papers in Press. Published Aug 9, 2012.