Fix the Eye and Save the Hip?

August 13, 2012
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There is a very interesting study in the August 1, 2012 issue of JAMA titled “Risk of Fractures Following Cataract Surgery in Medicare Beneficiaries.”  It has been known that visual changes related to cataracts are associated with postural instability.  Postural instability, in turn, is related to falls.  Falls in older folks, particularly if they have osteoporosis, can result in hip fractures.  And, hip fractures are a cause of morbidity and mortality in elders.

Victoria Tseng, MD and her colleagues decided to study whether removing cataracts would result in a reduced risk of hip fractures in Medicare beneficiaries. The researchers used the 5% random sample of Medicare beneficiaries from 2002 to 2010 to answer the question.

There were two groups of patients identified:

1)  Those with both a diagnosis code (ICD-9) for cataract and a procedural (CPT) code for cataract surgery

2.  Those with a diagnosis of cataract, but no claims evidence of cataract procedure during the study period

Claims were reviewed for hip fracture codes (both surgical and non-surgical) occurring during the year before and after date of surgery or in the case of the group without surgery, during the year after the diagnosis of cataract.

1,113,640 unique patients with a diagnosis code of cataract (366.xx) were found in the random sample.  Most were women (60%) and most were white (88%).  410,809 (37%) had cataract surgery during the study period.  The cataract surgery group was older than the cataract diagnosis group.  And, the prevalence of severe cataracts was significantly higher in the group that had surgery (no surprise here).

Cataract

The incidence of hip fracture during the study period was low, 1.3%, but still that represented 13,976 individuals.  After adjusting for demographics and comorbidities, the study showed lower odds of hip fratures in the cataract surgery group compared with the cataract diagnosis group – results were particularly good in the 80-84 year old age group.  The difference in absolute risk was 16% (0.20% vs. 0.24%).  The numbers needed to treat (e.g., have cataract surgery) to prevent a hip fracture was 507.

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Because the study was retrospective, observational, and used administrative data, the findings are suggestive, but not conclusive.  Thus, the authors state that “cataract surgery may be associated with lower odds of subsequent fracture in patients aged 65 and older in the US Medicare population.”  And, of course, they suggest that prospective studies be done to better determine the “potential benefit of cataract surgery” in the elderly.

If the results hold up, this is an important finding.  Cataract surgery has improved remarkably over the years and is now quite safe and usually delivers excellent outcomes.    Prevention of hip fracture, a traumatic event with signficant morbidity and mortality is a worthwhile goal.