Sally C. Stearns

ESTIMATING CONFIDENCE INTERVALS FOR COST‐EFFECTIVENESS RATIOS: AN EXAMPLE FROM A RANDOMIZED TRIAL

Cost-effectiveness ratios usually appear as point estimates without confidence intervals, since the numerator and denominator are both stochastic and one cannot estimate the variance of the estimator exactly. The recent literature, however, stresses the importance of presenting confidence intervals for cost-effectiveness ratios in the analysis of health care programmes. This paper compares the use of several methods to obtain confidence intervals for the cost-effectiveness of a randomized intervention to increase the use of Medicaids Early and Periodic Screening, Diagnosis and Treatment (EPSDT) programme. Comparisons of the intervals show that methods that account for skewness in the distribution of the ratio estimator may be substantially preferable in practice to methods that assume the cost-effectiveness ratio estimator is normally distributed. We show that non-parametric bootstrap methods that are mathematically less complex but computationally more rigorous result in confidence intervals that are similar to the intervals from a parametric method that adjusts for skewness in the distribution of the ratio. The analyses also show that the modest sample sizes needed to detect statistically significant effects in a randomized trial may result in confidence intervals for estimates of cost-effectiveness that are much wider than the boundaries obtained from deterministic sensitivity analyses.

Weight and wages: fat versus lean paychecks

Past empirical work has shown a negative relationship between the body mass index (BMI) and wages in most cases. We improve on this work by allowing the marginal effect of non-linear BMI groups to vary by gender, age, and type of interpersonal relationships required in each occupation. We use the National Longitudinal Survey of Youth 1979 (1982-1998). We find that the often-reported negative relationship between the BMI and wages is larger in occupations requiring interpersonal skills with presumably more social interactions. Also, the wage penalty increases as the respondents get older beyond their mid-twenties. We show that being overweight and obese penalizes the probability of employment across all race-gender subgroups except black women and men. Our results for the obesity-wage association can be explained by either consumers or employers having distaste for obese workers.

A prospective study of the impact of patient preferences on life-sustaining treatment and hospital cost.

OBJECTIVES Ethicists advise that life-sustaining treatment decisions should be made in keeping with patient preferences. Until recently, there has been little systematic study of the impact of patient preferences on the use of various life-sustaining treatments or the consequent cost of hospital care. This prospective study was designed to answer the following questions: a) Do patient treatment preferences about the use of life-sustaining treatment influence the treatments they receive? and b) Do patient treatment preferences influence the total cost of their hospitalization? DESIGN A prospective, cohort study. SETTING A university teaching hospital. PATIENTS Hospitalized patients, at least 50 yrs of age, with short life expectancy due to end-stage heart, lung, or liver disease, metastatic cancer, or lymphoma. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Patients were interviewed to determine their desire for life-sustaining treatment and other characteristics and then were followed for 6 months to determine life-sustaining treatment use and costs during hospitalization. Two hundred forty-four patients were interviewed. Fifty-eight percent of patients expressed a desire for life-sustaining treatments to prolong life for 1 wk. During 245 subsequent hospitalizations, there were 20 episodes of mechanical ventilation, 63 episodes of intensive care, and 66 cancer treatments given. Bivariate and multivariate analyses showed no significant association between patient desire to receive treatment to prolong life and either life-sustaining treatment use (p = .59) or hospital costs (p = .20). CONCLUSION In a university teaching hospital setting, there is no systematic evidence that patient preferences determine life-sustaining treatment use or hospital costs.

The Staffing–Outcomes Relationship in Nursing Homes

OBJECTIVE To assess longitudinally whether a change in registered nurse (RN) staffing and skill mix leads to a change in nursing home resident outcomes while controlling for the potential endogeneity of staffing. DATA SOURCES Minimum Data Set (MDS) nursing home resident assessment data from five states merged with Online Survey Certification and Reporting (OSCAR) data from 1996 through 2000. STUDY DESIGN Resident-level longitudinal analysis with facility fixed effects and instrumental variables. Outcomes studied are incidence of pressure sores and urinary tract infections. RN staffing was measured as the care hours per resident-day and skill mix was measured as RN staffing hours as a proportion of total staffing hours. DATA EXTRACTION METHOD We use all quarterly MDS assessments that fall within 120 days of an annual OSCAR data point, resulting in 399,206 resident-level observations. PRINCIPAL FINDINGS Controlling for endogeneity of staffing increases the estimated impact of staffing on outcomes in nursing homes. Greater RN staffing significantly decreases the likelihood of both adverse outcomes. Increasing skill mix only reduces the incidence of urinary tract infections. CONCLUSIONS Research that fails to account for endogeneity of the staffing-outcomes relationship may underestimate the benefit from increased RN staffing. Increases in RN staffing are likely to reduce adverse outcomes in some nursing homes. More research using a broader array of instruments and a national sample would be beneficial.

Understanding Biased Selection in Medicare HMOs

OBJECTIVE To investigate the extent of favorable health maintenance organization (HMO) selection for a longitudinal cohort of Medicare beneficiaries, examine whether the extent of favorable selection varies with the degree of Medicare HMO market penetration in a county, and explain conflicting findings in the literature on favorable HMO selection. DATA SOURCES A panel of 1992-1996 data from the Medicare Current Beneficiary Survey (MCBS), supplemented with linked data from the Area Resource File and Medicare administrative datasets. STUDY DESIGN Using random effects probit estimation, we model a beneficiarys HMO enrollment status as a function of self-reported health status and Medicare HMO market penetration. DATA EXTRACTION METHODS The MCBS data for beneficiaries residing in states served by Medicare HMOs in 1992-1996 were linked by county to the supplementary datasets. PRINCIPAL FINDINGS We find that favorable selection persists in the cohort over time on some, but not all, measures. We find no substantial association between favorable HMO selection and HMO market penetration. We find that conflicting findings in the literature on favorable HMO selection may be explained by several methodological choices, including the choice of health status measure and the structure of the sample. CONCLUSIONS Our results support further risk adjustment of the adjusted average per capita cost (AAPCC) payment formula.

Retirement and physical activity: analyses by occupation and wealth.

BACKGROUND Older adults close to retirement age show the lowest level of physical activity. Changes in lifestyle with retirement may alter physical activity levels. This study investigated whether retirement changes physical activity and how the effect differs by occupation type and wealth level. METHODS This longitudinal study used the Health and Retirement Study (1996-2002), U.S. population-based data. Analyses were conducted in 2007 and 2008. Physical activity was measured by a composite indicator of participation in either work-related or leisure-time physical activity. Fixed-effects regression models were used to account for confounders and unobserved heterogeneity. The dependent variable was a composite indicator of participation in regular physical activity either at work or during nonworking hours. RESULTS Physical activity decreased with retirement from a physically demanding job but increased with retirement from a sedentary job. Occupation type interacted with wealth level, with the negative impact on physical activity of retirement exacerbated by lack of wealth and the positive effect of retirement on physical activity enhanced by wealth. CONCLUSIONS Substantial differences in the effect of retirement on physical activity occurred across subgroups. As the number of people approaching retirement age rapidly increases, findings suggest that a growing segment of the nations population may not sustain an adequate level of physical activity.

Effectiveness of Preventive Dental Treatments by Physicians for Young Medicaid Enrollees

OBJECTIVE: To estimate the effectiveness of a medical office–based preventive dental program (Into the Mouths of Babes [IMB]), which included fluoride varnish application, in reducing treatments related to dental caries. METHODS: We used longitudinal claims and enrollment data for all children aged 72 months or younger enrolled in North Carolina Medicaid from 2000 through 2006. Regression analyses compared subgroups of children who received up to 6 IMB visits at ages 6 to 35 months with children who received no IMB visits. Analyses were adjusted for child and area characteristics. RESULTS: Children enrolled in North Carolina Medicaid with ≥4 IMB visits experienced, on average, a 17% reduction in dental-caries–related treatments up to 6 years of age compared with children with no IMB visits. When we simulated data for initial IMB visits at 12 and 15 months of age, there was a cumulative 49% reduction in caries-related treatments at 17 months of age. The cumulative effectiveness declined because of an increase in treatments from 24 to 36 months, an increase in referrals for dental caries occurred with increasing time since fluoride application, and emergence of teeth not initially treated with fluoride. CONCLUSIONS: North Carolinas IMB program was effective in reducing caries-related treatments for children with ≥4 IMB visits. Multiple applications of fluoride at the time of primary tooth emergence seem to be most beneficial. Referrals to dentists for treatment of existing disease detected by physicians during IMB implementation limited the cumulative reductions in caries-related treatments, but also contributed to improved oral health.

Increasing US rates of endocarditis with Staphylococcus aureus: 1999-2008.

Estimates of the incidence and impact of bacterial infective endocarditis (IE) have been limited by the infrequency of the disease. Administrative data analyses can provide important information across a broad range of hospitals and regions. We used a recent, nationally representative sample to estimate the incidence of hospitalizations for bacterial IE in the United States.

Reductions in hospital use from self management training for chronic asthmatics

The purpose of this study was to assess the impact of asthma Self Management Training on the health status and resource use of patients with chronic asthma. The study consisted of a randomized control design of chronic asthmatic patients in a tertiary care center in India. The intervention group (153 patients) received four training sessions in addition to the regular care provided to the control group (150 patients). Health status and resource use were measured at baseline and over a one year follow-up period. The intervention group had significantly better health status (measured by breathing ability), fewer productive days lost, and lower resource use (hospitalizations and emergency room visits) than the control group. Total annual costs (direct and indirect) were also lower, though physician costs were not included in the assessment. Therefore, incorporation of asthma Self Management Training as part of clinical management of asthma can result in improvements in health status and reductions in hospital use.

Treatment Outcomes and Costs of Dental Sealants Among Children Enrolled in Medicaid

OBJECTIVES This retrospective cohort analysis of children enrolled in the North Carolina Medicaid program compared the likelihood of restorative treatments and associated cumulative Medicaid expenditures for teeth with or without dental sealants. METHODS We assessed the dental experience of the cohort of 15 438 children from 1985 to 1992 on the basis of enrollment and claims files. We conducted regression analyses for outcomes (caries-related services involving the occlusal surface [CRSOs] of permanent first molars) and cumulative expenditures, controlling for characteristics of the child, the treating dentist, and the childs county of residence. RESULTS Overall, 23% of children received at least 1 sealant and 33% at least 1 CRSO. Sealants were effective in preventing CRSOs, although the degree of effectiveness was highest for children with the greater levels of CRSOs before sealant placement. Estimated cumulative Medicaid expenditures indicated expenditure savings from sealants within 2 years of application for children with 2 or more prior CRSOs. CONCLUSIONS Sealant placement was associated with expenditure savings to Medicaid for certain high-risk children, so Medicaid and, more broadly, society will benefit by providing for sealant placement in these children.