摘要：Objectives . This study examined the association between intermittent lack of health insurance coverage and use of preventive health services. Methods . Analyses focused on longitudinal data on insurance status and preventive service use among a national sample of US adults who participated in the Health and Retirement Study. Results . Findings showed that, among individuals who obtain insurance coverage after histories of intermittent coverage, relatively long periods may be necessary to reestablish clinically appropriate care patterns. Increasing periods of noncoverage led to successively lower rates of use of most preventive services. Conclusions . Intermittent lack of insurance coverage—even across a relatively long period—results in less use of preventive services. Studies that examine only current insurance status may underestimate the population at risk from being uninsured. Many studies have documented the efficacy of preventive health service use (e.g., cholesterol screenings, mammograms, Papanicolaou (Pap) tests) in reducing morbidity and mortality. 1 For example, according to Kiefe et al., “convincing scientific evidence shows that screening for either breast cancer or cervical cancer in appropriate age groups reduces mortality by 20% to 60%, depending on the condition and baseline risk level of the group being screened.” 2(p357) Uninsured adults are less likely than those with insurance to use preventive services than are those who are insured. 3– 5 The access barriers posed by lack of insurance coverage are especially significant for older adults, who have, in addition to preventive services needs similar to those of younger persons, a greater burden of chronic disease. Most studies of the uninsured population have focused on individuals who lack insurance coverage at the time they are interviewed or who have been uninsured for all of the previous year. In fact, health insurance coverage is quite dynamic, with many people being uninsured for substantial portions of a year or intermittently uninsured over several years. 6– 9 Recent studies have shown that among individuals who lack health insurance coverage for even relatively short periods of time, there is a significantly increased likelihood of delays in seeking recommended follow-up care, 10 care for chronic conditions, and clinically indicated preventive services. 11 Health insurance status can change frequently within a given year and over a period of several years; thus, most figures may substantially underestimate the pool of individuals who are potentially vulnerable to the effects of noncoverage. 8, 9, 11– 13 We recently reported that being continuously or intermittently uninsured increases the likelihood of adverse health outcomes among the near-elderly population. 14 To examine possible mechanisms in the causal pathway between insurance status and health outcomes, we undertook an analysis of the relationship between lack of health insurance coverage and use of preventive services. In contrast to previous studies, we used longitudinal data, available in the national Health and Retirement Study (HRS), to focus on how 2 different measures of insurance status—insurance status in 1994 and 1996 and episodes of noncoverage during 1992 through 1996—predicted use of preventive services among older adults over a 2-year reference period. These 2 insurance status measures allowed us to answer the following questions: (1) How does loss or acquisition of insurance affect the use of preventive services? and (2) Do multiple episodes of noncoverage increase the risk of underuse of preventive services?
