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Biomedical subjects

R Rosenman

Publications and source records attributed to R Rosenman.

18 recordsLinked to original sources
PubMed2001

Estimating hospital costs with a generalized Leontief function.

This paper estimates a long-run hospital cost function with multiple outputs and inputs using a panel data set from Washington State hospitals during 1988-1993. We find that with our data the generalized Leontief function is more appropriate than a translog for estimating hospital cost functions. With respect to hospital costs, we find that hospitals readily adjust the use of intermediate products. Radiology, therapies and surgery, and other inpatient days, all serve as substitutes for core inpatient days. Outpatient services are found to be complementary to core inpatient services, indicating that the growth of stand-alone outpatient clinics might increase the costs of providing healthcare services. Our analysis finds that hospitals show significant economies of scale, but there is a limited amount of evidence of scope economies. Also, there is some evidence that profit-seeking hospitals achieve some of their goals by controlling costs, and that diagnostically related groups (DRG)-based Medicare services are effective in getting hospitals to control costs.

Ambulatory Care↗
PubMed2001

Cost inefficiency in Washington hospitals: a stochastic frontier approach using panel data.

We analyze a sample of Washington State hospitals with a stochastic frontier panel data model, specifying the cost function as a generalized Leontief function which, according to a Hausman test, performs better in this case than the translog form. A one-stage FGLS estimation procedure which directly models the inefficiency effects improves the efficiency of our estimates. We find that hospitals with higher casemix indices or more beds are less efficient while for-profit hospitals and those with higher proportion of Medicare patient days are more efficient. Relative to the most efficient hospital, the average hospital is only about 67% efficient.

Data Collection↗
PubMed2000

Data envelopment analysis to determine efficiencies of health maintenance organizations.

We use Data Envelopment Analysis (DEA) to measure the relative technical efficiencies of 164 HMOs licensed to practice in the United States in 1995 with data collected from the American Association of Health Plans. Health care output measures used in the analysis are the number of commercial, Medicare and Medicaid lives covered in each plan. Inputs to the model are health care utilization measures such as the number of medical and surgical inpatient days, number of maternity and newborn stays in days, number of outpatient and emergency room visits and the number of non-invasive and invasive procedures performed on patients in an ambulatory setting. Mean efficiency of health plans was 40% (of the most efficient). We use multivariate analysis to try and explain variations in efficiency. Enrollment influences efficiency, with larger HMOs being more efficient than those with fewer enrollees. Plans with a more even distribution of Commercial, Medicare and Medicaid patients were more efficient on average than plans with heterogeneous mixes in enrollment. HMOs with Medicare patients are significantly less efficient, with efficiency decreasing with increasing Medicare participation in plan membership. Health plans in operation for longer periods of time had greater outputs with the same inputs. Health plans that had a majority of their enrollees in network or IPA type arrangements were more efficient as were for-profit plans compared to not-for-profits. Policy implications are discussed.

Chi-Square Distribution↗
PubMed2000

Causes of cost inefficiency in HMOs.

Estimates a total effects cost function using a national 1994 health maintenance organization (HMO) data set to examine and update findings related to HMO efficiency. The cost function controls for ownership characteristics (profit status and ownership), size, enrollment diversity, regional location, product diversity, model type, payment characteristics, and years of operation. While not explicitly controlling for quality or acuity, measures of plan and enrollee diversity help control for aculty and quality. Results show that most of the difference in cost efficiency between HMOs is explained by factors specific to the HMO, including efficiencies of scale and scope, lower levels of Medicare patients, and efficient levels of capital. The study also shows that for-profits are more efficient than non-profits because they rely less on withhold pools to control costs. Limitations of the study include weak controls for quality of care, and limited data related to payment characteristics.

Aged↗
PubMed1997

The impact of ownership on health care services in HMOs.

Tests the theory that owners (hospital, physician, insurance) of vertically integrated health maintenance organizations (HMOs) might substitute towards production of their own specialty goods. Uses data from various sources in the USA. Determines the impact of ownership on factors such as average physician ambulatory services per enrollee and average hospital days per enrollee. Concludes that policymakers need to encourage the development of standard publicly available quality measures to intensify competition and eliminate excess profits accruing to provider-owners who substitute towards production of their own goods.

Catchment Area, Health↗
PubMed1991

Long-term changes in Type A behavior: a 27-year follow-up of the Western Collaborative Group Study.

This study examined the long-term stability of Type A behavior pattern in the Western Collaborative Group Study for 1180 surviving participants in a 27-year follow-up examination during 1986-1987. Subjects were readministered the Structured Interview (SI), originally developed for this study and first administered at intake in 1960-1961. Subjects were also given the Jenkins Activity Survey (JAS) and were asked to evaluate their behaviors currently and in the past using two short descriptions of Type A and Type B behaviors. Analyses of changes in global SI ratings, JAS score, and self-ratings showed no relationships between self-perceived changes reported in questionnaires and observed changes when assessed by the SI. Using the SI ratings, 61% of subjects retained their initial classification and 39% of subjects were rated differently, with a higher percentage of those originally typed B being rerated as A than A being rerated as B. Type B subjects rerated as A were significantly younger, retired earlier, reported better health, and were less likely to have been in a managerial or professional position than the subjects who changed from A to B.

Adult↗
PubMed1988

Genetic heritability and shared environmental influences of type A measures in the NHLBI Twin Study.

Data from the NHLBI Twin Study were used to investigate the genetic component in a number of Type A measures given to these twins during a second cardiovascular examination. Specifically, the objective of the current study was to determine the extent to which various Type A measures are influenced by genetic effects and by measurable environmental and cultural factors. Analyses of these data for twins yielded a number of results. First, the Type A behavior pattern as assessed by the structured interview was only weakly associated with self-report inventories developed as alternatives to the structured interview. Second, among the self-report measures of Type A, only the Thurstone Temperament Schedule Active scale showed a clear significant genetic component. Most important, a number of demographic and social characteristics known to be associated with the various Type A scales had a differential effect on twin similarities. Specifically, for the job involvement subscale of the Jenkins Activity Survey, twins of both zygosities became equally similar after adjustments for covariates, while no effect on twin similarity was noted for the Thurstone Temperament Schedule Active scale. It is concluded that a complex constellation of genetic predispositions and acquired behaviors underlies the Type A behavior construct.

Aged↗
PubMed1987

Heritability of clinical chemistries in an older twin cohort: the NHLBI Twin Study.

Heritability analyses were performed with clinical chemistry data collected on 360 twin pairs of white, middle-aged male veterans during the second examination of the NHLBI Twin Study, a multicenter study of cardiovascular disease risk factors. Significant genetic variability was present for albumin, alkaline phosphatase, blood urea nitrogen, 1-hr postload glucose, phosphorus, total protein, and uric acid. Calcium and aspartate aminotransferase had significantly different means by zygosity, which precluded further analysis. Total bilirubin and lactate dehydrogenase did not show evidence for genetic variation at this examination. Comparisons are made to results from similar twin studies and the first examination of the NHLBI Twin Study. Heritability estimates for phosphorus and blood urea nitrogen exhibited marked stability across studies, while heritability estimates for total bilirubin, total protein, and uric acid decreased in older study populations. The heritability of 1-hr postload blood glucose decreased from 0.88 at the first NHLBI examination to 0.52 at the second one. Interpretation of these results requires consideration of possible selection biases, methodologic and demographic issues, and the view that for some clinical chemistries, biological aging along with prolonged environmental exposures may alter the amount of phenotypic variation explained by the additive effect of genes alone.

Adult↗
PubMed1987

Plasma cholesterol variation in the National Heart, Lung and Blood Institute Twin Study.

Plasma cholesterol was measured in the fifth decade of the life of 249 pairs of monozygotic (MZ) and 262 pairs of dizygotic (DZ) World War II veteran twins and 70% of the same cohort 10 years later. There were no significant differences between the mean cholesterol values for MZ and DZ twins, and the within DZ pair mean squares were significantly larger than the within MZ pair mean squares for all of the cholesterol variables measured. However, the DZ twins were found to have greater total variance, positive skewness, and leptokurtosis than the MZ twins for total and high-density lipoprotein cholesterol, and the total/high-density ratio. Comparisons with published data revealed that the variance of DZ twins was similar to that of singletons while the MZ twins have smaller total variance, perhaps owing to a missing component of variation. Hypotheses for the source of the differences in the zygosity distributions are proposed including environmental influences (pre- or post-natal and within- or among-families), genetic differences, and selection at the time of induction into the armed services. Because of the differences in total variance of the two zygosities it is difficult to know which estimates of genetic variance or heritability have the least bias. However, these data provide clues that may lead to further understanding of sources of plasma cholesterol variation that could be important to the future understanding of risk for coronary heart disease.

Cholesterol↗
PubMed1985

Familial resemblance on the Thurstone Activity Scale, systolic blood pressure, and total cholesterol among first degree relatives of subjects with and without coronary heart disease.

An investigation of the pattern of familial resemblance of three different risk factors assessed in families of coronary heart disease (CHD) patients and controls is presented. The fathers of these families participated in the Western Collaborative Group Study that first established the type A/B behavior pattern as an independent risk factor for CHD. A recently developed methodology, the Structured Exploratory Data Analysis (SEDA), was implemented to examine parental interaction, parent-offspring closeness, asymmetries in transmission, and other differences in the pattern of familial similarities among family members of case and control subjects. The analysis performed revealed pronounced parent-child similarity for total serum cholesterol values in both case and control families; spouse closeness and parent-child resemblance for systolic blood pressure measurements only in control families; and sex asymmetries in the parent-child closeness on pace of activity, which also differed between case and control families. The results of this investigation underscore the value of examining the joint pattern of familial resemblance of a number of risk factors as a means for differentiating between cultural and biological factors affecting familial aggregation of CHD.

Blood Pressure↗
PubMed1977

The NHLBI twin study of cardiovascular disease risk factors: methodology and summary of results.

Coronary heart disease (CHD) risk factors were studied in 250 monozygotic (MZ) and 264 dizygotic (DZ) male veteran twin pairs, aged 42-56. All coronary heart disease risk factors studied showed significant correlations in both MZ and DZ twins. Substantial genetic variation was detected for height, blood pressure, glucose intolerance, uric acid, plasma triglyceride, and relative weight but little or no significant genetic variability in low density lipoprotein cholesterol (LDL), high density lipoprotein cholesterol (HDL), total plasma cholesterol or hematocrit was demonstrable. These findings suggest that familial aggregation results from genetic influence on blood pressure, glucose intolerance, uric acid, triglyceride and, possibly, obesity, while largely shared environmental factors contribute to familial similarities in HDL, LDL, total cholesterol and hematocrit.

Adult↗
PubMed1976

Heritability of personality traits in adult male twins.

Personality test data from the California Psychological Inventory were collected on 99 pairs of identical and 99 pairs of fraternal adult male twins. Heritabilities were comuted for all 18 scales and compared to the heritabilities for "pure" scales with overlapping items omitted. Two of the pure scales, Responsibility and Femininity, had zero heritabilities, whereas all of the full scales had moderate to high heritabilities. It was concluded that item overlap has contributed significantly to previous failures to find evidence for the differential heritability of personality traits as measured by the CPI. CPI items were classified into genetic or environmental categories and separate factor analyses of items in these categories revealed more differences than similarities in factor structure. The genetic personality factors included Conversational Poise, Compulsiveness, and Social Ease. Environmental factors included Confidence in Leadership, Impulse Control, Philosophical Attitudes, Intellectual Interest, and Exhibitionism. Compared to the genetic factors, each of the environmental factors accounted for only a very small percentage of the variance.

Adult↗
PubMedDate not supplied

Output efficiency of health maintenance organizations in Florida.

We use data envelopment analysis (DEA) to measure the relative technical efficiencies of 28 HMOs licensed to practice in the State of Florida in the autumn of 1994. Health care output measures used in the analysis are number of commercial, Medicare and Medicaid members enrolled in each plan. Inputs to the model are capital assets, total expenditures on the provision of medical services and administrative expenses. We find differences in HMO efficiency scores and loss ratios (defined as the ratio of expenses on the provision of medical services to the total expenses incurred by the organization) across individual plans. Differences in efficiency measures across model type (staff, IPA, combination) and ownership types (for-profit, not-for-profit) are small but significant: staff models and for-profits are more efficient. In a multivariate model, we also find that large HMOs are more efficient and HMOs with Medicaid patients are significantly less efficient than other HMOs.

Ambulatory Care↗