Breast cancer patients age 65 years and older who were enrolled in one of two large western not-for-profit health maintenance organizations (HMOs) experienced long-term survival equal to or better than counterparts living in the same geographic areas who received breast cancer care under the traditional fee-for-service (FFS) system. The HMO members were also more likely than the FFS patients to receive breast-conserving surgery and to have adjuvant radiation therapy recommended for early-stage breast cancer. The study by Arnold L. Potosky, phD, National Cancer Institute, and colleagues was reported in the Journal of the National Cancer Institute.
The authors note that enrollment in HMOs has increased rapidly during the past 10 years, reflecting a growing emphasis in the United States on health-care cost containment. As of 1996, 20% of the US population received health care through HMOs, they report, and more than 11% of Medicare beneficiaries were enrolled in HMOs in 1996.
There is growing public concern, say Potosky and coworkers, that the rapid growth of the managed-care industry may limit access to treatment for some patients with serious illnesses. According to the authors, study results to date comparing clinical outcomes between HMO and FFS settings have been mixed, and most did not adequately adjust for baseline differences in health status.
To determine whether there are differences in treatment and outcome for older female patients with breast cancer enrolled in HMOs vs an FFS setting, the researchers compared the 10-year survival and initial treatment of women with breast cancer enrolled in both types of plans.
Using tumor registry, Medicare, and health plan data, information was obtained on the treatment and outcome of 13,358 breast cancer patients, age 65 years and older, whose cancer was diagnosed between 1985 and 1992. The patients were enrolled in Kaiser Permanente of Northern California, an established prepaid group model HMO serving San Francisco-Oakland and surrounding areas; Group Health Cooperative of Puget Sound, a large staff model HMO serving the Seattle-Puget Sound area; or traditional indemnity health insurance plans in these geographic areas. Patients in all plans were followed for a maximum of 10 years through December 1994, and the median follow-up time was 52 months.
In addition to comparing treatment and survival outcomes, the researchers investigated the influence of other variables known to influence prognosis, including age, race, tumor stage, socioeconomic status, and comorbidity.
After adjusting for tumor stage, comorbidity, and sociodemographic characteristics, the 10-year adjusted risk for breast cancer death among HMO patients in San Francisco-Oakland was 29% lower than for FFS patients in this geographic area. In Seattle-Puget Sound, 10-year survival was essentially equal for HMO and FFS patients.
After adjusting for the same variables used to adjust survival differences, it was found that Seattle-area HMO patients with early-stage breast cancer were 3.4 times more likely to receive breast-conserving surgery (as opposed to a mastectomy) than FFS patients in that geographic area and 4.6 times more likely to receive radiotherapy after surgery. In San Francisco-Oakland, HMO patients were 1.6 times more likely to receive breast-sparing surgery and 2.5 times more likely to receive adjuvant radiotherapy, compared with FFS patients.
The authors also found that women in the HMOs were more likely to be diagnosed at an earlier stage of disease than women receiving FFS care. They believe that these findings reflect more frequent breast cancer screening in the HMO population and note that these two HMOs are integrated systems of care in which referrals to specialists are simpler than in some other managed-care or FFS settings. Potosky and colleagues also suggest that the survival advantage observed among the HMO patients could be explained, in part, by screening and the participation of healthier individuals in HMO plans, but that these factors are unlikely to account entirely for the survival differences.
Results Cannot Be Generalized
The researchers emphasize that various types of managed-care settings differ markedly in history and organization. Not-for-profit group and staff model plans with integrated hospital and primary-care systems differ, for example, from for-profit independent practice associations with capitated payment structures and contractual relationships between primary and specialty care providers.
Thus, they caution, the current results cannot be generalized to all managed-care settings. Potosky and colleagues believe further research is needed to assist consumers, providers, and policy-makers in understanding the effects of specific health-care delivery organizational structures and financing mechanisms on treatment and outcomes for women with breast cancer.
In an accompanying editorial, Sheldon M. Retchin, MD, MSPH, Virginia Commonwealth University, Richmond, describes important health plan attributes and market characteristicsincluding for-profit or not-for-profit status, provider relationships and payment arrangements, market share, managed-care penetration, and enrollee demographicsthat may account for some of the variation in treatment and outcomes observed at Kaiser Permanente of Northern California and Group Health Cooperative of Puget Sound, large not-for-profit plans with similar roots. These variables, he says, may vary widely in different types of managed-care plans and in the for-profit setting and are extremely influential in the quality of health care delivered in these systems. Noting that no two health plans are alike, Retchin concludes by recounting the aphorism, if youve seen one HMO, youve seen one HMO.