Cataracts are the leading cause of visual impairment worldwide affecting more than 20 million people. Statins are among the most commonly prescribed medications. In the USA they are prescribed to 1 in 3 people over 45 years of age at a cost of $35 billion annually.
Professor Kostis said: "There is persistent concern among physicians and other health care providers about the possible cataractogenicity of statins.1 We therefore investigated the relationship of statins and cataracts in a meta-analysis of 14 studies selected after detailed review of the medical literature. To our knowledge this is the first meta-analysis on the topic."
The meta-analysis included 2,399,200 persons and 25,618 cataracts. The average duration of treatment was 54 months and average age was 61.
Using random effects meta-analysis, a statistically significant decrease in cataracts with statins was observed (odds ratios [OR] 0.80, 95% confidence interval [CI] 0.77-0.83, p<0.0001). Professor Kostis said: "This corresponds to an approximately 20% lower rate of cataracts with statin use compared to no statin use."
Absolute risk reduction was 1.4%+0.015% (95% CI 1.1%-1.7%, p<0.0001). Professor Kostis said: "This equates to 71 persons needed to treat (NNT) with statins to prevent one cataract (95% CI 59-91 persons)."
Meta-regression showed that younger people were more likely to benefit, with an OR of 0.50 for patients in their 40s and an OR of 0.90 for patients in their 70s. Professor Kostis said: "Our analysis shows that people in their 40s who use statins have a 50% lower chance of getting cataracts. For people in their 70s risk is lowered by just 10%. It is possible that the two processes (aging and statins) work in parallel or interactively."
The analysis showed an increase in benefit of statins with longer duration of treatment with the OR varying from 0.90 for a treatment duration of 6 months (a 10% reduction in risk) to 0.45 for a treatment duration of 14 years (a 55% reduction in risk).
There was no difference between studies by gender. Several sensitivity analyses confirmed the results.
Professor Kostis concluded: "This meta-analysis indicates a statistically significant and clinically relevant protective effect of statins in preventing cataracts. The effect is more pronounced in younger patients, and with longer use. Our findings dispel worries about the safety of statins when it comes to cataracts, and lends additional support to long term statin use."
Extraction: Studies pertaining to removal of cataract by an operation; No Extraction: Studies where removal of cataract by an operation was not the endpoint; Clinical: Studies where the patient or a physician reported the presence of cataract; Opacities: Studies where an ophthalmologist reported the presence small areas of cloudiness in the lens of the eye unrelated to visual complaints by the patients.
Notes to editor
1 Cataracts were considered a side effect of statins in early studies. High doses of lovastatin, the first Food and Drug Administration (FDA) approved statin, caused cataracts in beagle dogs. In 1987 lovastatin was approved for human use with the precaution "that patients placed on lovastatin therapy be examined with a slit-lamp before and shortly after initiation of treatment, and annually thereafter". This recommendation was removed from the labelling by the FDA in 1991. Prior publications have reported inconsistent findings on the effect of statins on cataract. Recently, Machan et al. reported that in the Waterloo Eye Study statin use was substantially higher in patients with type 2 diabetes and was associated with cataracts. Also, recent data on statins indicate continuing concern among patients, pharmacists and other health care providers as reported in electronic drug information sites. Facts and Comparisons state that in the package inserts cataract is associated with the statin class. Micromedex states that cataracts have been reported in postmarketing studies for all statins and Lexi-Comp reports a rate of visual impairment of 1.6% for pravastatin.
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