Confirming a trend that has been observed for other types of surgery, a new study has found that Medicare patients in managed care plans are only half as likely to undergo vision-saving cataract surgery as are those in traditional fee-for-service plans.
But the study was not designed to assess whether the managed care patients are being underserved or the fee-for-service patients are receiving unnecessary surgery, a team from UCLA, USC and Rand Corp. report today in the Journal of the American Medical Assn.
“The most important conclusion to draw is that managed care clearly has the ability to alter health care delivery patterns,” said Dr. Jonathan Javit of the Cleveland Clinic. “It may be good, it may be bad, or it may be both.”
But the unusual demographics of the patients hint that the managed care patients, particularly women, are not being treated effectively, according to Dr. Caroline Lubick Goldzweig of UCLA, who led the study.
“What this does is raise a red flag that there are big differences in the likelihood that patients will receive surgery depending on where they are getting their health care,” Goldzweig said.
About 1.4 million cataract operations are performed in the United States each year and, at an annual cost of $3.4 billion, such surgeries represent the largest single expenditure by Medicare.
“Cataract surgery is probably the most cost-effective surgical procedure known to man,” Javit said. Denying it to a patient who has symptoms to control costs “would be unconscionable,” he added.
Cataracts are a cloudiness in the lens of the eye caused when proteins in the clear fluid clump together, impeding the passage of light. Although they can be caused by diabetes and certain other conditions, the most common cause is aging.
More than half of all Americans over age 65 have a cataract, and untreated cataracts remain a leading cause of blindness.
Cataract surgery entails removing the cloudy lens. Vision can then be restored by inserting a plastic lens in its place, or with special glasses or contact lenses. More than 90% of all patients who undergo cataract surgery have better vision afterward, according to the National Eye Institute. The success rate climbs to 98% among patients who have no complicating factors, such as glaucoma or diabetes.
Patients who do not have the surgery have an impaired ability to function and are significantly more likely to suffer falls, hip fractures and other accidents.
Some previous studies comparing managed care to traditional medical services have found that one way in which HMOs reduce cost is by restricting access to expensive surgery. The rates of gallbladder removals, hysterectomies, appendectomies, tonsillectomies and caesarean sections have been found to be lower in prepaid plans than in fee-for-service care.
At the opposite extreme, critics charge that some fee-for-service surgeons perform unnecessary operations to bolster their profits.
Goldzweig and her colleagues studied the 43,387 Medicare beneficiaries who were enrolled in a large Southern California HMO in 1993 and the 19,050 who were enrolled in an affiliated independent practice association, a slightly different form of prepaid care. The HMO, which sponsored the research, was not identified.
The team compared these groups to 47,150 Medicare beneficiaries who received fee-for-service care. They found that there were 35 cataract surgeries per 1,000 patient-years in the fee-for-service group, but only 22 per 1,000 in the IPA and just 17 per 1,000 in the HMO.
What was “really interesting,” Goldzweig said, were the gender differences. Women normally have about a 50% higher incidence of cataracts than men and a comparable edge in surgery. That was reflected among the fee-for-service patients, where the number of surgeries among women was double that among the men.
In both the HMO and the IPA, women and men had equal numbers of surgeries. “This implies that whatever gate-keeping is in place does not act the same on men as on women,” said Dr. Oliver D. Schein of the Johns Hopkins School of Medicine. “There is something about the system that changes the natural history [of cataracts] that we have seen over and over again.”
The authors concede that a variety of factors could explain the differences in rates between the two types of plans. HMO members might, for example, have had their cataract surgeries at an earlier stage, thereby reducing the pool of people who needed the surgery. Or private surgeons may be performing too many operations.
One troublesome possibility is reflected in reports from Florida and elsewhere that some HMOs are encouraging members who need cataract surgery to drop out of the prepaid plan and enroll in a fee-for-service plan to obtain the surgery. Such cost-shifting, experts say, is unethical.