HMO coverage reduces variations in the use of health care among patients under age sixty-five

Health Affairs

Volumn 29, Issue 11, 2010, Pages 2068-2074

  Baker, Laurence C ^a   Kate Bundorf, M ^b   Kessler, Daniel P ^c  

^a STANFORD UNIVERSITY SCHOOL OF MEDICINE   (United States)

^b NATIONAL BUREAU OF ECONOMIC RESEARCH   (United States)

^c STANFORD UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ARTICLE; HEALTH CARE QUALITY; HEALTH CARE SURVEY; HEALTH MAINTENANCE ORGANIZATION; HEALTH SERVICE; HOSPITALIZATION; HUMAN; INSURANCE; MIDDLE AGED; ORGANIZATION AND MANAGEMENT; UNITED STATES; UTILIZATION REVIEW;

HEALTH CARE SURVEYS; HEALTH MAINTENANCE ORGANIZATIONS; HEALTH SERVICES; HOSPITALIZATION; HUMANS; INSURANCE COVERAGE; MIDDLE AGED; PROGRAM EVALUATION; UNITED STATES;

EID: 79952279269     PISSN: 02782715     EISSN: 15445208     Source Type: Journal    
DOI: 10.1377/hlthaff.2009.0810     Document Type: Article

References (21)

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2. Fisher ES, Wennberg DE, Stukel TA, Gottlieb DJ, Lucas FL, Pinder EL. The implications of regional variations in Medicare spending, part 2: health outcomes and satisfaction with care. Ann of Intern Med. 2003;138(4): 288-98.
3. Skinner JS, Fisher ES, Wennberg JE. The efficiency of Medicare. In: Wise DA, editor. Analyses of the economics of aging. Chicago (IL): University of Chicago Press; 2005. p. 129-57.
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6. Stiefel M, Feigenbaum P, Fisher ES. The Dartmouth Atlas applied to Kaiser Permanente: analysis of variation in care at the end of life. Perm J. 2008;12(1):4-9.
7. Age 45 is a standard cutoff for comparisons in health services research. See Note 14 below. 8 Cutler DM, McClellan MB, Newhouse JP. How does managed care do it? RAND J Econ. 2000; 31(3):526-48.
8. Cutler DM, McClellan MB, Newhouse JP. How does managed care do it? RAND J Econ. 2000; 31(3):526-48.
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10. The twelve areas are Boston, MA; Cleveland, OH; Greenville, SC; Indianapolis, IN; Lansing, MI; Little Rock, AR; Miami, FL; Newark, NJ; Orange County, CA; Phoenix, AZ; Seattle, WA; and Syracuse, NY.
11. This survey design provides more accurate information about the details of people's insurance than respondent self-reports. Analyses of the responses by enrollees and plan representatives to questions about plan characteristics indicate that enrollees often do not know basic information about their plans. Cunningham PJ, Denk C, Sinclair M. Do consumers know how their health plan works? Health Aff (Millwood). 2001;20(2):159-66.
12. A plot of the two series can be found in the Online Appendix. To access this document, click on the Online Appendix link in the box to the right of the article online. We excluded Medicare Advantage enrollees from the CTS analysis because they are excluded from the Dartmouth Atlas statistics.
13. We present the data underlying Exhibits 1-3 in tabular form in the Online Appendix, as in Note 12.
14. For our comparisons of people with unmanaged and HMO insurance, we risk-adjusted the area-level measures of utilization for differences across areas in the race, sex, age, and income of the population. This riskadjustment method had three steps. First, we ran individual-level regressions, separately for people with HMO and unmanaged insurance, of utilization on race, sex, area fixed effects, and categorical variables for age and household income. Second, we calculated what each area's regression- adjusted utilization would be if it had the national average race, sex, age, and income distribution. Third, we calculated the coefficient of variation of this regressionadjusted utilization across areas.
15. To calculate the p values, we used the following two-step method. First, we replaced each person's actual utilization with his or her predicted utilization from the regression in step 1 in Note 14 plus a bootstrapped residual from this regression, drawn with replacement separately for each of the twelve geographic areas. Second, we repeated steps 1-3 two thousand times, which generated a distribution of differences in the coefficients of variation for people with unmanaged and HMO insurance. The p-value we report is based on the standard error of this distribution.
16. Available online as in Note 12.
17. Reschovsky JD, Kemper P, Tu H. Does type of health insurance affect health care use and assessments of care among the privately insured? Health Serv Res. 2000;35(1):219-37.
18. Miller RH, Luft HS. HMO plan performance update: an analysis of the literature, 1997-2001. Health Aff (Millwood). 2002;21(4):63-86.
19. Centers for Disease Control and Prevention, National Center for Health Statistics. Table 57 in Health, United States, 2009 [Internet]. Hyattsville (MD): NCHS; 2009 [cited 2010 Sep 29]. Available from: http://www.cdc.gov/nchs/hus.htm
20. Philipson TJ, Seabury SA, Lockwood L, Goldman D, Lakdawalla D. Regional variations in health care: the role of private markets. Brookings Papers on Econ Activity; forthcoming.
21. The medical loss ratio measures the fraction of total premium revenue that health plans devote to clinical services, as distinct from administration and profit.