Market reform in New Jersey and the effect on mortality from acute myocardial infarction

OBJECTIVE: To determine whether mortality rates for patients with acute myocardial infarction (AMI) changed in New Jersey after implementation of the Health Care Reform Act, which reduced subsidies for hospital care for the uninsured and changed hospital payment to price competition from a rate-setting system based on hospital cost. DATA SOURCES/STUDY SETTING: Patient discharge data from hospitals in New Jersey and New York from 1990 through 1996 and the Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample (NIS). STUDY DESIGN: A comparison between states over time of unadjusted and risk-adjusted mortality and cardiac procedure rates. DATA COLLECTION: Discharge data were obtained for 286,640 patients with the primary diagnosis of AMI admitted to hospitals in New Jersey or New York from 1990 through 1996. Records of 364,273 NIS patients were used to corroborate time trends. PRINCIPAL FINDINGS: There were no significant differences in AMI mortality among insured patients in New Jersey relative to New York or the NIS. However, there was a relative increase in mortality of 41 to 57 percent among uninsured New Jersey patients post-reform, and their rates of expensive cardiac procedures decreased concomitantly. CONCLUSIONS: The introduction of hospital price competition and reductions in subsidies for hospital care of the uninsured were associated with an increased mortality rate among uninsured New Jersey AMI patients. A relative decrease in the use of cardiac procedures in New Jersey may partly explain this finding. Additional studies should be done to identify whether other market reforms have been associated with changes in the quality of care.     

Hospital financing and neonatal intensive care.

OBJECTIVE: To investigate the relationship between hospital financing patterns and hospital resources for the care of babies born at low birthweight in New York City. DATA SOURCES AND STUDY SETTING: Data on neonatal care beds in New York City hospitals for 1991, obtained from the Greater New York Hospital Association, which were matched to 1991 hospital-specific birthweight and payment distributions from the New York State Department of Health. STUDY DESIGN: Statistical analyses were used to assess the relationship between insurance and beds across all hospitals and across hospitals classified by ownership and teaching status. PRINCIPAL FINDINGS: After adjusting for low birthweight and other measures of patient need and for hospital affiliation, the study finds that hospitals with more privately insured patients, especially those with more privately insured low-birthweight newborns, have statistically significantly more neonatal intensive care beds than do those with fewer such patients. This result persists within hospital affiliation categories. CONCLUSIONS: These results suggest that differences in the care received by privately insured, Medicaid insured, and uninsured low-birthweight babies may stem from differences in the resources available to the hospitals that treat these patients.     

New York's statistical model accurately predicts mortality risk for veterans who obtain private sector CABG

OBJECTIVE: To determine whether patients' use of the Veterans Health Administration health care system (VHA) is an independent risk factor for mortality following coronary artery bypass grafting (CABG) in the private sector in New York. DATA SOURCES: VHA administrative and New York Department of Health Cardiac Surgery Reporting System (CSRS) databases for surgeries performed in 1999 and 2000. STUDY DESIGN: Prospective cohort study comparing observed, expected, and risk-adjusted mortality rates following private sector CABG for 2,326 male New York State residents aged 45 years and older who used the VHA (VHA users) and 21,607 who did not (non-VHA users). DATA COLLECTION METHODS: We linked VHA administrative databases to New York's CSRS to identify VHA users who obtained CABG in the private sector in New York in 1999 and 2000. Using CSRS risk factors and previously validated risk-adjustment model, we compared patient characteristics and expected and risk-adjusted mortality rates of VHA users to non-VHA users. PRINCIPAL FINDINGS: Compared with non-VHA users, patients undergoing private sector CABG who had used the VHA were older, had more severe cardiac disease, and were more likely to have the following comorbidities associated with increased risk of mortality: diabetes, chronic obstructive pulmonary disease, cerebrovascular disease, peripheral vascular disease, and history of stroke (p<.001 for all); a calcified aorta (p=.009); and a high creatinine level (p=.003). Observed (2.28 versus 1.80 percent) and expected (2.48 versus 1.78 percent) mortality rates were higher for VHA users than for non-VHA users. The risk-adjusted mortality rate for VHA users (1.70 percent; 95 percent confidence interval [CI]: 1.27-2.22) was not statistically different than that for the non-VHA users (1.87 percent; 95 percent CI: 1.69-2.06). Use of the VHA was not an independent risk factor for mortality in the risk-adjustment model. CONCLUSIONS: Although VHA users had a greater illness burden, use of the VHA was not found to be an independent risk factor for mortality following private sector CABG in New York. The New York Department of Health risk adjustment model adequately applies to veterans who obtain CABG in the private sector in New York.     

Acute Myocardial Infarction in New York State: 1996–2008

We examined the Acute Myocardial Infarction (AMI) incidence and mortality rates in New York State for a recent 13-year period. Hospital discharge data and death certificate information are combined to create patient episodes for AMI. Trends in the risk-adjusted AMI incidence and mortality are examined for the years 1996 through 2008. Between 1996 and 2008, the AMI incidence rate declined by 35.8% and AMI mortality fell from 161.0 to 71.6 per 100,000 population. This 55.5% decline in mortality is accompanied by a 23.9% decline in the number of AMI admissions to acute care hospitals and by a 37.8% improvement in mortality among those hospitalized. New York State follows the national trend in decline in AMI. That decline is accompanied by reductions in AMI mortality, reduced demand on hospitals, and significant improvement in hospital care quality among AMI patients.     

The Effect of Cuts in Medicare Reimbursement on Hospital Mortality

Objective. To determine if patients treated at hospitals under different levels of financial strain from the Balanced Budget Act (BBA) of 1997 had differential changes in 30-day mortality, and whether vulnerable patient populations such as the uninsured were disproportionately affected.
Data Source. Hospital discharge data from all general acute care hospitals in Pennsylvania from 1997 to 2001.
Study Design. A multivariate regression analysis was performed retrospectively on 30-day mortality rates, using hospital discharge data, hospital financial data, and death certificate information from Pennsylvania.
Data Collection. We used 370,017 hospital episodes with one of four conditions identified by the Agency for Healthcare Research and Quality as inpatient quality indicators were extracted.
Principal Findings. The average magnitude of Medicare payment reduction on overall net revenues was estimated at 1.8 percent for hospitals with low BBA impact and 3.6 percent for hospitals with a high impact in 1998, worsening to 2 and 4.8 percent, respectively, by 2001. Operating margins decreased significantly over the time period for all hospitals ( p <.05). While unadjusted mortality rates demonstrated a disproportionate rise in mortality for patients from high impact hospitals from 1997 to 2000, adjusted analyses show no consistent, significant difference in the rate of change in mortality between high-impact and low-impact hospitals ( p =.04–.94). Similarly, uninsured patients did not experience greater increases in mortality in high-impact hospitals relative to low-impact hospitals.
Conclusions. An analysis of hospitalizations in the Commonwealth of Pennsylvania did not find an adverse impact of increased financial strain from the BBA on patient mortality either among all patients or among the uninsured.     

Hospital competition, managed care, and mortality after hospitalization for medical conditions in California

OBJECTIVE: To assess the effect of hospital competition and health maintenance organization (HMO) penetration on mortality after hospitalization for six medical conditions in California. DATA SOURCE: Linked hospital discharge and vital statistics data for short-term general hospitals in California in the period 1994-1999. The study sample included adult patients hospitalized for one of the following conditions: acute myocardial infarction (N=227,446), hip fracture (N=129,944), stroke (N=237,248), gastrointestinal hemorrhage (GIH, N=216,443), congestive heart failure (CHF, N=355,613), and diabetes (N=154,837). STUDY DESIGN: The outcome variable was 30-day mortality. We estimated multivariate logistic regression models for each study condition with hospital competition, HMO penetration, hospital characteristics, and patient severity measures as explanatory variables. PRINCIPAL FINDINGS: Higher hospital competition was associated with lower 30-day mortality for three to five of the six study conditions, depending on the choice of competition measure, and this finding was robust to a variety of sensitivity analyses. Higher HMO penetration was associated with lower mortality for GIH and CHF. CONCLUSIONS: Hospitals that faced more competition and hospitals in market areas with higher HMO penetration provided higher quality of care for adult patients with medical conditions in California. Studies using linked hospital discharge and vital statistics data from other states should be conducted to determine whether these findings are generalizable.     

Impact of managed care on the treatment, costs, and outcomes of fee-for-service Medicare patients with acute myocardial infarction

OBJECTIVE: To examine the effects of market-level managed care activity on the treatment, cost, and outcomes of care for Medicare fee-for-service acute myocardial infarction (AMI) patients. DATA SOURCES/STUDY SETTING: Patients from the Cooperative Cardiovascular Project (CCP), a sample of Medicare beneficiaries discharged from nonfederal acute-care hospitals with a primary discharge diagnosis of AMI from January 1994 to February 1996. STUDY DESIGN: We estimated models of patient treatment, costs, and outcomes using ordinary least squares and logistic regression. The independent variables of primary interest were market-area managed care penetration and competition. The models included controls for patient, hospital, and other market area characteristics. DATA COLLECTION/EXTRACTION METHODS: We merged the CCP data with Medicare claims and other data sources. The study sample included CCP patients aged 65 and older who were admitted during 1994 and 1995 with a confirmed AMI to a nonrural hospital. PRINCIPAL FINDINGS: Rates of revascularization and cardiac catheterization for Medicare fee-for-service patients with AMI are lower in high-HMO penetration markets than in low-penetration ones. Patients admitted in high-HMO-competition markets, in contrast, are more likely to receive cardiac catheterization for treatment of their AMI and had higher treatment costs than those admitted in low-competition markets. CONCLUSIONS: The level of managed care activity in the health care market affects the process of care for Medicare fee-for-service AMI patients. Spillovers from managed care activity to patients with other types of insurance are more likely when managed care organizations have greater market power.     

Racial Variation in End‐of‐Life Intensive Care Use: A Race or Hospital Effect?

OBJECTIVE: To determine if racial and ethnic variations exist in intensive care (ICU) use during terminal hospitalizations, and, if variations do exist, to determine whether they can be explained by systematic differences in hospital utilization by race/ethnicity. DATA SOURCE: 1999 hospital discharge data from all nonfederal hospitals in Florida, Massachusetts, New Jersey, New York, and Virginia. DESIGN: We identified all terminal admissions (N = 192,705) among adults. We calculated crude rates of ICU use among non-Hispanic whites, blacks, Hispanics, and those with "other" race/ethnicity. We performed multivariable logistic regression on ICU use, with and without adjustment for clustering of patients within hospitals, to calculate adjusted differences in ICU use and by race/ethnicity. We explored both a random-effects (RE) and fixed-effect (FE) specification to adjust for hospital-level clustering. DATA COLLECTION: The data were collected by each state. PRINCIPAL FINDINGS: ICU use during the terminal hospitalization was highest among nonwhites, varying from 64.4 percent among Hispanics to 57.5 percent among whites. Compared to white women, the risk-adjusted odds of ICU use was higher for white men and for nonwhites of both sexes (odds ratios [ORs] and 95 percent confidence intervals: white men = 1.16 (1.14-1.19), black men = 1.35 (1.17-1.56), Hispanic men = 1.52 (1.27-1.82), black women = 1.31 (1.25-1.37), Hispanic women =1.53 (1.43-1.63)). Additional adjustment for within-hospital clustering of patients using the RE model did not change the estimate for white men, but markedly attenuated observed differences for blacks (OR for men =1.12 (0.96-1.31), women = 1.10 (1.03-1.17)) and Hispanics (OR for men =1.19 (1.00-1.42), women = 1.18 (1.09-1.27)). Results from the FE model were similar to the RE model (OR for black men = 1.10 (0.95-1.28), black women = 1.07 (1.02-1.13) Hispanic men = 1.17 (0.96-1.42), and Hispanic women = 1.14 (1.06-1.24)) CONCLUSIONS: The majority of observed differences in terminal ICU use among blacks and Hispanics were attributable to their use of hospitals with higher ICU use rather than to racial differences in ICU use within the same hospital.     

Availability of safety net providers and access to care of uninsured persons

OBJECTIVE: To understand how proximity to safety net clinics and hospitals affects a variety of measures of access to care and service use by uninsured persons. DATA SOURCES: The 1998-1999 Community Tracking Study household survey, administered primarily by telephone survey to households in 60 randomly selected communities, linked to data on community health centers, other free clinics, and safety net hospitals. STUDY DESIGN: Instrumental variable estimation of multivariate regression models of several measures of access to care (having a usual source of care, unmet or delayed medical care needs, ambulatory service use, and overnight hospital stays) against endogenous measures of distances to the nearest community health center and safety net hospital, controlling for characteristics of uninsured persons and other area characteristics that are related to access to care. The models are estimated with data from a nationally representative sample of uninsured people. PRINCIPAL FINDINGS: Shorter distances to the nearest safety net providers increase access to care for uninsured persons. Failure to account for the endogeneity of distance to safety net providers on access to care generally leads to finding little or no safety net effects on access. CONCLUSIONS: Closer proximity to the safety net increases access to care for uninsured persons. However, the improvements in access to care are relatively small compared with similar measures of access to care for insured persons. Modest expansion of the safety net is unlikely to provide a full substitute for insurance coverage expansions.     

Reconsidering the effect of Medicaid on health care services use.

OBJECTIVE: Our research compares health care use by Medicaid beneficiaries with that of the uninsured and the privately insured to measure the program's effect on access to care. DATA SOURCES/STUDY SETTING: Data include the 1987 National Medical Expenditure Survey and the Survey of Income and Program Participation for 1984-1988. STUDY DESIGN: We predict annual use of ambulatory care and inpatient hospital care for Medicaid beneficiaries receiving AFDC cash assistance and compare it to what their use would be if uninsured or if covered by private insurance. Comparisons are based on multivariate models of health care use that control for demographic and economic characteristics and for health status. Our model distinguishes among Medicaid beneficiaries on the basis of eligibility to account for the poor health of beneficiaries in some eligibility groups. PRINCIPAL FINDINGS: AFDC Medicaid beneficiaries use considerably more ambulatory care and inpatient care than they would if they remained uninsured. Use among the AFDC Medicaid population is about the same as use among otherwise similar, privately insured persons. Use rates differ substantially among different Medicaid beneficiary groups, supporting the expectation that some beneficiary groups are in poor health. CONCLUSIONS: Although Medicaid has increased access to health care services for beneficiaries to rates now comparable to those for the privately insured population, because of lower cost sharing in Medicaid we would expect higher service use than we are finding. This suggests possible barriers to Medicaid patients in receiving the care they demand. Enrollment of less healthy individuals into some Medicaid beneficiary groups suggests that pooled purchasing arrangements that include Medicaid populations must be designed to ensure adequate access for the at-risk populations and, at the same time, to ensure that private employers do not opt out because of high community-rated premiums.     

Children’s Receipt of Health Care Services and Family Health Insurance Patterns

PURPOSE Insured children in the United States have better access to health care services; less is known about how parental coverage affects children’s access to care. We examined the association between parent-child health insurance coverage patterns and children’s access to health care and preventive counseling services.METHODS We conducted secondary analyses of nationally representative, cross-sectional, pooled 2002–2006 data from children (n = 43,509), aged 2 to 17 years, in households responding to the Medical Expenditure Panel Survey (MEPS). We assessed 9 outcome measures pertaining to children’s unmet health care and preventive counseling needs.RESULTS Cross-sectionally, among US children (aged 2 to 17 years) living with at least 1 parent, 73.6% were insured with insured parents, 8.0% were uninsured with uninsured parents, and the remaining 18.4% had discordant family insurance coverage patterns. In multivariable analyses, insured children with uninsured parents had higher odds of an insurance coverage gap (odds ratio [OR] = 2.45; 95% confidence interval [CI], 2.02–2.97), no usual source of care (OR = 1.31; 95% CI, 1.10–1.56), unmet health care needs (OR = 1.11; 95% CI, 1.01–1.22), and having never received at least 1 preventive counseling service (OR = 1.20; 95% CI, 1.04–1.39) when compared with insured children with insured parents. Insured children with mixed parental insurance coverage had similar vulnerabilities.CONCLUSIONS Uninsured children had the highest rates of unmet needs overall, with fewer differences based on parental insurance status. For insured children, having uninsured parents was associated with higher odds of going without necessary services when compared with having insured parents.     

An exploration of the complex relationship of socioecologic factors in the treatment and outcomes of acute myocardial infarction in disadvantaged populations

OBJECTIVE: To examine the relationship of patients' socioeconomic status (SES) as measured by race, health insurance status, and median income by zip code to in-hospital mortality of acute myocardial infarction (AMI), paying special attention to patients with multiple unfavorable socioeconomic risk factors. DATA SOURCES/STUDY SETTING: The data set was abstracted from patient-level hospital discharges in the Nationwide Inpatient Sample, Release 3, 1994. A total of 95,971 AMI discharges in 11 states were extracted. STUDY DESIGN: The risk adjustment methodology was adapted from the California Hospital Outcomes Project. Risk factors included demographic and clinical characteristics. Patients in double jeopardy had inferior insurance status and lived in poorer neighborhoods. PRINCIPAL FINDINGS: Compared with patients with health care coverage under Medicare and private insurance uninsured AMI patients had the highest risk-adjusted mortality odds and Medicaid AMI patients had the second highest odds. Probably because of the modest association of median income by zip code areas with mortality odds, the double jeopardy phenomenon was not observed. However, compared to patients who had two favorable SES attributes, patients who carried two unfavorable SES attributes had much higher mortality risk, more comorbidities, longer length of stay, and higher total hospital charges, while they received fewer AMI specialized procedures. Race did not seem to be a significant factor after adjustment for other SES attributes. CONCLUSIONS: SES is significantly related to the mortality of AMI patients. The disadvantaged patients receive fewer specialized procedures, possibly because of their higher levels of severity and financial barriers. The variation in mortality between patients who had favorable and unfavorable SES becomes wider when multiple socioeconomic risks are borne by the latter.     

Comparing uninsured and privately insured hospital patients: admission severity, health outcomes and resource use.

This paper compares uninsured hospital patients with privately insured patients in terms of severity of illness on admission, emergency department use, leaving the hospital against medical advice, length of stay, and in-hospital mortality and morbidity rates. This cross-sectional study includes 29,237 admissions to 100 US hospitals in 1993 and 1994. We found that uninsured patients are sicker, indicating that hospitals should expect uninsured patients to have increased service needs. Our results indicate that the uninsured exhibit higher likelihood of leaving against medical advice, shorter lengths of stay and poorer health outcomes suggest that the uninsured may not be receiving necessary care. Further studies are needed.     

The effect of hospital discharge price increases on publicly reported measures of quality

Objective

To determine if increases in hospital discharge prices are associated with improvements in clinical quality or patient experience.

Data Sources

This study used Medicare cost report data and publicly available Medicare.gov Care Compare quality measures for approximately 3000 short-term care general hospitals between 2011 and 2018.

Study Design

We separately regressed quality measure scores on a lag of case mix adjusted discharge price, hospital fixed effects, and year indicators. Clinical quality measures included 30-day readmission rates for acute myocardial infarction, chronic obstructive pulmonary disease, heart failure, hip and knee replacement, and pneumonia; risk-adjusted 30-day mortality rates for acute myocardial infarction, chronic obstructive pulmonary disease, heart failure, and stroke; and 90-day complication rate for hip and knee replacement. Patient experience measures included the summary star rating and 10 domain measures reported through the Hospital Consumer Assessment of Healthcare Providers and Systems survey. We tested for heterogeneous effects by hospital ownership, number of beds, the commercial share of overall discharges, and market concentration.

Data Collection/Extraction Methods

We linked hospitals identified in Medicare cost reports to Medicare.gov Care Compare quality measures. We excluded hospitals for which we could not identify a discharge price or that had an unrealistic price.

Principal Findings

There was no positive association between lagged discharge price and any clinical quality measure. For patient experience measures, a 2% increase in discharge price was not associated with overall patient satisfaction but was associated with small, statistically significant increases ranging from 0.01% to 0.02% (relative to mean scores) for seven of ten domain measures. There was a positive association for five of ten patient experience measures in competitive markets and one measure in both moderately concentrated and heavily concentrated markets.

Conclusions

We found no evidence that hospitals use higher prices to make investments in clinical quality; patient experience improved, but only negligibly.     

Overcoming the Odds: Access to Care for Immigrant Children in Working Poor Families in California

Objectives: To explore the extent to which, among working poor families, uninsured immigrant children experience more barriers to care than uninsured nonimmigrants, and compare these differences to those of insured children. Methods: We used data from the 2001 California Health Interview Survey, a randomized, population-based telephone survey conducted from November 2000 through September 2001. Financial and nonfinancial access to health care and utilization of health services were examined for 3,978 nonimmigrant and 462 immigrant children and adolescents under the age of 18 years. We compared differences in crude rates across four subgroups (insured immigrants, uninsured immigrants, insured nonimmigrants, uninsured nonimmigrants) and in adjusted models controlling for socioeconomic and immigration characteristics, parental language, health status, and other demographic factors. Results: More immigrant than nonimmigrant children lacked health insurance at the time of the interview (44% vs. 17%, p < 0.0001). Among the uninsured, immigrants had higher odds of perceiving discrimination (11% vs. 5%, p < 0.05) and postponing emergency room (ER) (16% vs. 7%, p < 0.05) and dental care (40% vs. 30%, p < 0.05) after controlling for covariates. Among the insured, immigrants fared worse on almost every access and utilization outcome. Among insured immigrants, child and parent undocumented status and having a non-English-speaking parent contributed to missed physician and ER visits. Conclusions: Disparities in access and use remain for immigrant poor children despite public insurance eligibility expansions. Insurance does not guarantee equitable health care access and use for undocumented children. Financial and nonfinancial barriers to health care for immigrant children must be removed if we are to address disparities among minority children.     

Primary Cesarean Section Rates in Uninsured, Medicaid and Insured Populations of Predominantly Rural Northern New England

Many studies in the United States during the past two decades have reported consistently lower cesarean section rates in women of lower socioeconomic status as defined by census tract, insurance status, or maternal level of educational attainment. This study sought to determine whether cesarean section rates in predominantly rural northern New England are lower for lower, compared with higher socioeconomic groups, as they are reported nationally and in more urban areas. Age-adjusted, primary cesarean section rates for privately insured, Medicaid and uninsured women were calculated using 1990 to 1992 uniform hospital discharge data for Maine, New Hampshire and Vermont. Age-adjusted cesarean section rates for insured women (15.71 percent) were significantly higher than those for Medicaid (14.35 percent) and uninsured (12.85 percent) women. These differences in the cesarean section rate between the insured and poorer populations in northern New England are much less than those reported elsewhere in the country.     

Measuring hospital mortality rates: are 30-day data enough? Ischemic Heart Disease Patient Outcomes Research Team.

OBJECTIVE. We compare 30-day and 180-day postadmission hospital mortality rates for all Medicare patients and those in three categories of cardiac care: coronary artery bypass graft surgery, acute myocardial infarction, and congestive heart failure. DATA SOURCES/COLLECTION. Health Care Financing Administration (HCFA) hospital mortality data for FY 1989. STUDY DESIGN. Using hospital level public use files of actual and predicted mortality at 30 and 180 days, we constructed residual mortality measures for each hospital. We ranked hospitals and used receiver operating characteristic (ROC) curves to compare 0-30, 31-180, and 0-180-day postadmission mortality. PRINCIPAL FINDINGS. For the admissions we studied, we found a broad range of hospital performance when we ranked hospitals using the 30-day data; some hospitals had much lower than predicted 30-day mortality rates, while others had much higher than predicted mortality rates. Data from the time period 31-180 days postadmission yield results that corroborate the 0-30 day postadmission data. Moreover, we found evidence that hospital performance on one condition is related to performance on the other conditions, but that the correlation is much weaker in the 31-180-day interval than in the 0-30-day period. Using ROC curves, we found that the 30-day data discriminated the top and bottom fifths of the 180-day data extremely well, especially for AMI outcomes. CONCLUSIONS. Using data on cumulative hospital mortality from 180 days postadmission does not yield a different perspective from using data from 30 days postadmission for the conditions we studied.     

Overcoming bias in estimating the volume-outcome relationship

OBJECTIVE: To examine the effect of hospital volume on 30-day mortality for patients with congestive heart failure (CHF) using administrative and clinical data in conventional regression and instrumental variables (IV) estimation models. DATA SOURCES: The primary data consisted of longitudinal information on comorbid conditions, vital signs, clinical status, and laboratory test results for 21,555 Medicare-insured patients aged 65 years and older hospitalized for CHF in northeast Ohio in 1991-1997. STUDY DESIGN: The patient was the primary unit of analysis. We fit a linear probability model to the data to assess the effects of hospital volume on patient mortality within 30 days of admission. Both administrative and clinical data elements were included for risk adjustment. Linear distances between patients and hospitals were used to construct the instrument, which was then used to assess the endogeneity of hospital volume. PRINCIPAL FINDINGS: When only administrative data elements were included in the risk adjustment model, the estimated volume-outcome effect was statistically significant (p=.029) but small in magnitude. The estimate was markedly attenuated in magnitude and statistical significance when clinical data were added to the model as risk adjusters (p=.39). IV estimation shifted the estimate in a direction consistent with selective referral, but we were unable to reject the consistency of the linear probability estimates. CONCLUSIONS: Use of only administrative data for volume-outcomes research may generate spurious findings. The IV analysis further suggests that conventional estimates of the volume-outcome relationship may be contaminated by selective referral effects. Taken together, our results suggest that efforts to concentrate hospital-based CHF care in high-volume hospitals may not reduce mortality among elderly patients.     

The effect of competitive pressure on charity: hospital responses to price shopping in California

Since higher charges to private patients are a major source of financing for hospital care to the uninsured, increased price shopping by private payers may mean that hospitals are less able to provide such care. I study the effect of increased price shopping on California hospital markets over the 1984-1988 period. I find that there was a large fall in net private revenues and net income in the least concentrated hospital markets in the state after the advent of price shopping. Perhaps as a result, care to the uninsured fell dramatically in these markets as well, relative to more concentrated markets.