For some, statins may encourage cataract development

While statins have a clearly positive effect on cardiovascular disease risk, research suggests the role statins may have on the development of cataracts may cloud risk-benefit considerations for some patients.

In a retrospective look at statin users found in two North American databases, researchers attempted to clarify how frequently cataracts develop in these patients to determine if a connection might exist. Previous research into the association hasn’t been clear-cut.

Comparing statin users against nonusers from both databases between 2000 and 2011, Staphanie J. Wise, MD, of the Department of Ophthalmology and Visual Sciences at the University of British Columbia in Vancouver, Canada, and colleagues determined that there was an apparent connection. Four cohorts existed in the data: statin users and nonusers from British Columbia databases and statin users and nonusers from the U.S. provided by the IMS LifeLink database.

IMS LifeLink is a large health claims database in the U.S. with information on physician visits, hospitalizations and prescription drug use.

They found the adjusted rate ratio for development of cataracts in British Columbia statin users was the largest at 1.27. For the U.S. groups, the rate ratio for statin use developing cataracts was 1.07 after adjustment.

Absolute risk for cataracts was calculated at 20 per 1,000 person-years for statin users in the British Columbia cohort and 15 per 1,000 person-years for those not taking statins. In the U.S. cohorts, nonusers had a 20 per 1,000 person-years absolute risk and 24 per 1,000 person-years absolute risk for statin users. Wise et al calculated the need-to-harm as being between 40 and 50 for five years between the two statin-using cohorts.

Rate ratios per type of statin ranged between 1.14 and 1.42 for lovastatin (Mevacor, Merck) and rosuvastatin (Crestor, Astra Zeneca), respectively, in the British Columbia cohort and 1.03 to 1.14 for fluvastatin (Lescol, Novartis) and lovastatin, respectively, in the U.S. cohort.

They suggested that rates and risk were low enough that while discussion and disclosure with patients of cataract risk should happen, it should not deter physicians from prescribing statins.

In an editorial, Steven E. Gryn, MD, and Robert A. Hegele, MD, from Western University in London, Ontario, wrote that the findings needed to be confirmed. "As with the statin-diabetes correlation, the risk of cataracts is greatest amongst individuals who are already predisposed to develop them," they wrote. "However, the findings should not be taken out of context, especially considering the potential benefits of statins for patients with increased CVD [cardiovascular disease] risk.”

While these findings provide food for thought, Wise et al noted that they did have difficulties based on how the data was culled in pinpointing potential confounders, such as smoking. However, they suggested that further studies address these and other possible mechanisms involved in cataract development among statin users.

This study was published in the December issue of the Canadian Journal of Cardiology.