Howell Embry M, Dubay Lisa, Kenney Genevieve, Sommers Anna S
Urban Institute, Washington, DC 20037, USA.
Health Serv Res. 2004 Aug;39(4 Pt 1):825-46. doi: 10.1111/j.1475-6773.2004.00260.x.
To examine the impact of mandatory HMO enrollment for Medicaid-covered pregnant women on prenatal care use, smoking, Cesarean section (C-section) use, and birth weight.
DATA SOURCES/STUDY SETTING: Linked birth certificate and Medicaid enrollment data from July 1993 to June 1998 in 10 Ohio counties, 6 that implemented mandatory HMO enrollment, and 4 with low levels of voluntary enrollment (under 15 percent). Cuyahoga County (Cleveland) is analyzed separately; the other mandatory counties and the voluntary counties are grouped for analysis, due to small sample sizes. Study Design. Women serve as their own controls, which helps to overcome the bias from unmeasured variables such as health beliefs and behavior. Changes in key outcomes between the first and second birth are compared between women who reside in mandatory HMO enrollment counties and those in voluntary enrollment counties. County of residence is the primary indicator of managed care status, since, in Ohio, women are allowed to "opt out" of HMO enrollment in mandatory counties in certain circumstances, leading to selection. As a secondary analysis, we compare women according to their HMO enrollment status at the first and second birth.
DATA COLLECTION/EXTRACTION METHODS: Linked birth certificate/enrollment data were used to identify 4,917 women with two deliveries covered by Medicaid, one prior to the implementation of mandatory HMO enrollment (mid-1996) and one following implementation. Data for individual births were linked over time using a scrambled maternal Medicaid identification number.
The effects of HMO enrollment on prenatal care use and smoking were confined to Cuyahoga County, Ohio's largest county. In Cuyahoga, the implementation of mandatory enrollment was related to a significant deterioration in the timing of initiation of care, but an improvement in the number of prenatal visits. In that county also, women who smoked in their first pregnancy were less likely to smoke during the second pregnancy, compared to women in voluntary counties. Women residing in all the mandatory counties were less likely to have a repeat C-section. There were no effects on infant birth weight. The effects of women's own managed care status were inconsistent depending on the outcome examined; an interpretation of these results is hampered by selection issues. Changes over time in outcomes, both positive and negative, were more pronounced for African American women.
With careful implementation and attention to women's individual differences as in Ohio, outcomes for pregnant women may improve with Medicaid managed care implementation. Quality monitoring should continue as Medicaid managed care becomes more widespread. More research is needed to identify the types of health maintenance organization activities that lead to improved outcomes.
研究强制医疗保健组织（HMO）参保对医疗补助计划覆盖的孕妇产前护理利用、吸烟情况、剖宫产（C -section）使用及出生体重的影响。
数据来源/研究背景：1993 年 7 月至 1998 年 6 月俄亥俄州 10 个县的出生证明与医疗补助计划参保数据相链接，其中 6 个县实施了强制 HMO 参保，4 个县自愿参保水平较低（低于 15%）。凯霍加县（克利夫兰）单独分析；其他强制参保县和自愿参保县因样本量小而合并分析。研究设计：女性自身作为对照，这有助于克服健康观念和行为等未测量变量产生的偏差。比较居住在强制 HMO 参保县和自愿参保县的女性在首次和第二次生育时关键结局的变化。居住县是管理式医疗状况的主要指标，因为在俄亥俄州，女性在某些情况下可在强制参保县“选择退出”HMO 参保，从而导致选择偏倚。作为次要分析，我们根据女性在首次和第二次生育时的 HMO 参保状况进行比较。
数据收集/提取方法：利用链接的出生证明/参保数据识别出 4917 名有两次医疗补助计划覆盖分娩的女性，一次在强制 HMO 参保实施前（1996 年年中），一次在实施后。通过打乱顺序的产妇医疗补助识别号随时间链接个体出生数据。
HMO 参保对产前护理利用和吸烟的影响仅限于俄亥俄州最大的县凯霍加县。在凯霍加县，强制参保的实施与护理开始时间显著恶化相关，但产前检查次数有所改善。在该县，与自愿参保县的女性相比，首次怀孕吸烟的女性在第二次怀孕时吸烟的可能性较小。居住在所有强制参保县的女性进行再次剖宫产的可能性较小。对婴儿出生体重没有影响。女性自身的管理式医疗状况的影响因所检查的结局而异；选择问题妨碍了对这些结果的解释。非裔美国女性结局随时间的变化，无论是积极的还是消极的，都更为明显。
如在俄亥俄州那样谨慎实施并关注女性个体差异，医疗补助计划管理式医疗的实施可能改善孕妇结局。随着医疗补助计划管理式医疗的更广泛推行，应持续进行质量监测。需要更多研究来确定能带来更好结局的健康维护组织活动类型。
