Effect of insurance on mortality in an HIV-positive population in care
Effect of insurance on mortality in an HIV-positive population in care
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DOI：
10.1198/016214501753208582
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发表时间：
2001-09-01
影响因子：
3.7
通讯作者：
Morton, SC
中科院分区：
文献类型：
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作者：
Goldman, DR;Bhattacharya, J;Morton, SC
在决策者考虑扩大对感染人类免疫缺陷病毒（艾滋病毒）的个人的保险覆盖范围时，询问保险是否对健康结果有任何影响是有用的，如果有，其程度是否随着最近有效但昂贵的治疗而改变。通过使用来自全国代表性的接受定期医疗护理的HIV感染者（HIV+）队列的数据，我们估计了保险对这一人群死亡率的影响。一个简单的单方程模型证实了其他人在文献中发现的反常结果-保险增加了HIV+患者的死亡概率。我们将这一发现归因于死亡率方程中未观察到的健康状况和保险状况之间的相关性，原因有二。首先，医疗补助和医疗保险的资格规则要求HIV+患者证明残疾，几乎总是定义为晚期疾病，以符合资格，其次，如果未观察到的健康状况是正相关的原因，那么包括HIV+疾病作为对照的措施应该减轻影响。包括免疫功能（CD 4淋巴细胞计数）的措施减少了约50%的影响大小，虽然它没有改变符号。为了处理这种相关性，我们开发了一个双方程参数模型的保险和死亡率。保险对死亡率的影响是通过明智地使用国家政策变量作为工具来确定的（变量与保险状况有关，但与死亡率无关，除非通过保险）。该模型的结果表明，保险确实对结局有有益的影响，基线时6个月死亡率降低71%，随访时降低85%。随访中的较大影响可归因于最近引入的有效艾滋病毒感染疗法，这些疗法扩大了艾滋病毒阳性患者的保险回报（以死亡率衡量）。
As policymakers consider expanding insurance coverage for individuals infected with human immunodeficiency virus (HIV), it is useful to ask if insurance has any affect on health outcomes and, if so, whether its magnitude has changed with recent efficacious but expensive treatments. By using data from a nationally representative cohort of HIV-infected (HIV+) persons receiving regular medical care, we estimate the impact of insurance on mortality in this population. A naive single-equation model confirms the perverse result found by others in the literature-that insurance increases the probability of death for HIV+ patients. We attribute this finding to a correlation between unobserved health status and insurance status in the mortality equation for two reasons. First, the eligibility rules for Medicaid and Medicare require HIV+ patients to demonstrate a disability, almost always defined as advanced disease, to qualify, Second, if unobserved health status is the cause of the positive correlation, then including measures of HIV+ disease as controls should mitigate the effect. Including measures of immune function (CD4 lymphocyte counts) reduces the effect size by approximately 50%, although it does not change sign. To deal with this correlation, we develop a two-equation parametric model of both insurance and mortality. The effect of insurance on mortality is identified through the judicious use of state policy variables as instruments (variables related to insurance status but not mortality, except through insurance). The results from this model indicate that insurance does have a beneficial effect on outcomes, lowering the probability of 6-month mortality by 71% at baseline and 85% at follow-up. The larger effect at followup can be attributed to the recent introduction of effective therapies for HIV infection, which have magnified the returns to insurance for HIV+ patients (as measured by mortality rates).