Davidson B N, Sofaer S, Gertler P
Health Policy Research Division, SysteMetrics, Santa Barbara, CA 93101.
Soc Sci Med. 1992 May;34(9):1023-34. doi: 10.1016/0277-9536(92)90133-b.
This study examines how the relationship between health insurance knowledge and the health status of health insurance consumers influences their decisions to purchase insurance coverage. Data from the federal Medicare health insurance program for the elderly in the United States are used. The basic Medicare program provides a limited amount of coverage for health care services obtained from any provider in the private fee-for-service (FFS) market. Beneficiaries of this program may choose to supplement the basic coverage which they receive by two mechanisms: either they may purchase private insurance designed to fill some of the gaps left by the federal program ('Medigap' policies), thereby remaining in the FFS market and preserving their choice of provider, or they may enroll in health maintenance organizations (HMOs), thereby leaving the FFS market and agreeing to use only those providers affiliated with the HMO, and in return receiving broader coverage at little additional out-of-pocket cost. The study was made possible by a unique data set which combines measures of beneficiary knowledge of Medicare coverage with measures of perceived health status, socio-economic characteristics, and insurance coverage choices for a sample of Medicare beneficiaries who participated in an educational workshop about their insurance coverage options. These data were used to estimate a multinomial logistic model of the determinants of insurance choices, where the options included the two listed above and a basic Medicare option. The study explicitly recognizes the interaction between insurance information and health status in health plan choice. These results show that knowledge of coverage does have a differential impact on the decision to purchase health insurance depending on health status. With a high level of knowledge, sicker beneficiaries are less likely to have basic Medicare alone, compared with HMOs or Medigap policies, while healthier beneficiaries are less likely to be enrolled in HMOs, compared with Medigap policies. This finding has important implications for the use of health status measures to adjust capitated payment formulas when knowledgable consumers have the option to enroll in HMOs or remain in the FFS environment. In the absence of health status adjusters for the HMO capitation payments, high levels of coverage knowledge may exacerbate inherent selection bias among these coverage options by healthier and sicker consumers of health insurance.
本研究考察了医疗保险知识与医疗保险消费者健康状况之间的关系如何影响他们购买保险的决策。研究使用了来自美国联邦医疗保险计划（面向老年人）的数据。基本医疗保险计划为从私营按服务收费（FFS）市场的任何提供者处获得的医疗服务提供有限的保险范围。该计划的受益人可以通过两种机制选择补充他们所获得的基本保险范围：他们可以购买旨在填补联邦计划留下的一些空白的私人保险（“弥补性保险”政策），从而留在FFS市场并保留他们对提供者的选择；或者他们可以加入健康维护组织（HMO），从而离开FFS市场并同意仅使用与HMO相关联的那些提供者，作为回报，以很少的额外自付费用获得更广泛的保险范围。这项研究得益于一个独特的数据集，该数据集将医疗保险覆盖范围的受益人知识测量与参与了关于其保险覆盖选项的教育研讨会的医疗保险受益人的样本的感知健康状况、社会经济特征和保险覆盖选择测量相结合。这些数据被用于估计保险选择决定因素的多项逻辑模型，其中选项包括上述两种以及基本医疗保险选项。该研究明确认识到在健康计划选择中保险信息与健康状况之间的相互作用。这些结果表明，根据健康状况，保险覆盖知识对购买医疗保险的决策确实有不同的影响。在知识水平较高的情况下，与HMO或弥补性保险政策相比，病情较重的受益人单独拥有基本医疗保险的可能性较小，而与弥补性保险政策相比，健康状况较好的受益人加入HMO的可能性较小。这一发现对于在有知识的消费者可以选择加入HMO或留在FFS环境时使用健康状况测量来调整按人头付费公式具有重要意义。在缺乏针对HMO人头付费的健康状况调整因素的情况下，高水平的保险覆盖知识可能会加剧健康状况较好和较差的医疗保险消费者在这些保险覆盖选项之间固有的选择偏差。
