In previous studies the association between statin use and cataracts has been inconsistent and controversial.
However, according to Dr Robert Hegele, MD: “Even among lower-risk patients, for whom the benefit-risk ratio is less dramatic, most patients would still probably prefer having to undergo earlier non-life-threatening cataract surgery over suffering a major vascular event.”
The current study used data from the British Columbia Ministry of Health databases from 2000 to 2007 and the IMS LifeLink US database from 2001 to 2011 to form two patient cohorts.
The British Columbia cohort was composed of fale and male patients; 162,501 cases were matched with 650,004 controls. The IMS LifeLink cohort was comprised of males only, aged 40 to 85 years; 45,065 cases were matched with 450,650 controls.
Patients using statins for more than one year prior to initial ophthalmology examination were identified. Diagnosis and surgical managent of cataracts were followed.
In the BC cohort, there was about a 27 per cent increased risk of developing cataracts requiring surgical intervention (adjusted risk ratio [RR], 1.27). In the IMS cohort, the increased risk was only 7%, but still significant.
The adjusted RRs for long-term regular use of specific statins in the BC cohort ranged from 1.14 to 1.42. In the IMS cohort, the adjusted RRs for individual statins varied within a narrow range from 1.03 to 1.14. The investigators did not determine whether certain statins were worse than others, but most confidence intervals overlapped suggesting a class effect.
“Further assessment of the clinical impact of this relationship is recommended, especially given increased statin use for primary prevention of CVD [cardiovascular disease] and the importance of acceptable vision in old age where CVD is common,” Dr John Mancini, MD, of the Department of Medicine, University of British Columbia in Vancouver, said.
“Future studies addressing the possible underlying mechanisms to explain this association are also warranted. However, because the RR is low and because cataract surgery is both effective and well tolerated, this association should be disclosed but not be considered a deterrent to use of statins when warranted for CV risk reduction.”
In an accompanying editorial, Dr Steven Gryn, MD, and Dr Robert Hegele, MD, of the Schulich School of Medicine and Dentistry, Western University, London, Ontario, wrote: “Any medication that has beneficial effects has potential adverse effects; weighing the benefits against the risks is an integral part of the informed consent process, and is central to any decision to initiate treatment.
“Among patients who are at high CVD risk, like most of those seen by cardiologists … the prevention of CVD, stroke, and their associated morbidity and mortality vastly outweighs the risk of cataracts.
In any observational study, there can be unknown confounders that could introduce bias. Both the study itself and the commentary note this weakness, but both agree that this study, while not putting the issue to rest, does add significantly to the accumulated knowledge about the statin-cataract connection.
However, as Dr Hegele noted: “A randomised double-blinded placebo-controlled clinical trial is the best way to mitigate confounding, and such studies so far have shown no association of statins with cataracts.”
