A large US study of older people with a diagnosis of cataract, finds that the risk of hip fracture is lower following cataract surgery, suggesting the vision-improving surgery may reduce the odds of injury-related falls.
The study, which appears in the 1 August online issue of JAMA, reports how researchers examined data on over a million Medicare patients aged 65 and over with a diagnosis of cataract and found those who underwent cataract surgery had a lower odds of hip fracture 1 year after the procedure, compared with those who did not have the surgery.
The reduction was greatest among those with severe cataract.
Previous studies have found a strong link between visual impairment and higher risk of fractures, a significant cause of illness and death in the elderly. The study authors note that fall-related injuries cost the US over $10 billion in the year 2000.
In their background information, first author Victoria Tseng, of Brown University, Providence, Rhode Island, and colleagues, write:
“Specifically, vision plays an important role in providing a reference frame for postural balance and stability, and cataract-induced changes in vision have been found to be associated with postural instability.”
“Furthermore, cataracts have been found to be the most common cause of fracture-related visual impairment, with untreated cataract causing up to 49 percent of visual impairment in patients with femoral neck fractures related to decreased vision,” they add.
However, despite this, they suggest not enough research has been done to see if cataract surgery reduces these injuries.
Cataract is a condition where the lens in the eye becomes cloudy, resulting in blurred vision. Most cases occur in older adults, and by age 75 most people have cataracts.
However, cataract surgery, usually a straightforward outpatient procedure done under local anasthetic, corrects the condition by replaced the faulty lens with a clear synthetic one. In the US, the success rate is over 95%.
For their study, Tseng and colleagues examined the records of a 5% random sample of Medicare Part B beneficiaries (1,113,640 patients) with a diagnosis of cataract between 2002 and 2009. Medicare Part B is the outpatient medical services section of the US national social insurance program for the over- 65s.
60% of the participants were women, 88% were white, and a third were aged between 65 and 69.
36.9% (410,809) of participants had cataract surgery over the study period, during which 1.3% of them (13,976) experienced hip fractures.
When they analyzed the data, and adjusted for various potential influencing factors, the researchers found 1 year after the eye procedure, the risk of hip fracture was 16% lower among patients who had cataract surgery compared to those who did not.
Among patients diagnosed with severe cataract, the odds of hip fracture 1 year after cataract surgery was reduced even further, by 23%, compared with the cataract diagnosis group, write the authors.
The most common co-existing fracture-related illness was osteoporosis, which was diagnosed in 12.1% of patients. The most common co-existing eye illness was glaucoma (19.1% of patients).
The authors say prospective studies should now be done, using standardized registries of patients with cataracts, to improve the understanding of the link between cataract surgery and fracture risk.
There is already evidence that the procedure is a cost-effective way to improve vision. Estimates show the surgery reduces health costs by over $2,000 per patient, per year in the US, especially when the surgery is done on both eyes.
We now need a similar calculation to show what effect the procedure has on reducing fractures in the elderly, say the authors.
Written by Catharine Paddock PhD