Prediction rules for patients with suspected myocardial infarction. Applying guidelines in community hospitals.

Several clinical prediction rules have been developed to assist physicians in managing intensive care resources for patients with suspected myocardial infarction. These guidelines, developed in university settings, attempt to identify patients at high or low risk for developing life-threatening complications or death. Since some prediction rules have not performed well when applied to different patient populations, we applied these rules to 397 patients with suspected myocardial infarction who were admitted to community hospital coronary care units. The relative risk of dying associated with an abnormal initial electrocardiogram declined from 17 in the academic center to 2.9 in the community hospital. In contrast, a guideline that uses data available after 24 hours of observation did segregate patients at higher and lower risk in both the community and academic hospitals. This study shows that clinical prediction rules that were developed in academic medical centers should be validated before applying them in community hospital settings.

Small area analysis of hospital discharges for musculoskeletal diseases in Michigan: the influence of socioeconomic factors.

PURPOSE: The rise in health care costs has occasioned a number of initiatives in an attempt to reduce the rate of increase. Despite the growth of health maintenance organizations and preferred provider organizations and the introduction of Medicare's prospective payment system, health care costs have continued to increase. Coincident with these efforts, a number of researchers have shown that there exists wide variation in age-adjusted hospital discharge rates, which translate into significant variation in per capita expenditures. Much of the focus on the reasons for hospital admission variability has been on physician practice variation. If most of the variation in hospital discharge rates is due to physician practice style, then payment systems can be developed (e.g., capitation) that limit physician practice variation without harming patients. We examined socioeconomic factors in Michigan communities to assess their association with hospital discharge rates for patients with musculoskeletal diseases. PATIENTS AND METHODS: Data on hospital discharges from 1980 and 1987 were taken from the Michigan Inpatient Data Base. All admissions from the major diagnostic category 8, diagnosis-related group (DRG) 209-256 were included. Zip code-specific hospitalization data were grouped into small geographic areas or hospital market communities (HMCs). Discharge rates were calculated, and profiles of the socioeconomic characteristics of each of the HMCs were developed. A Poisson regression model with an extrasystematic component of variance was used to analyze the association of HMC socioeconomic characteristics with age-adjusted hospital use. RESULTS: We found that four socioeconomic variables, average annual income per capita, percent of the population with four years of college, percent of the population living in an urban area, and percent of families with incomes below the poverty line, explained 26.6% (R2) of the variation in overall hospital discharge rates (p less than 0.001). Moreover, we found that the ability of the model to explain variability was influenced by the type of disease, and that these socioeconomic variables had a consistent effect across the range of DRGs. Finally, we noted that, over the period of 1980 to 1987, socioeconomic factors remained important in explaining hospital use despite the dramatic changes in the delivery of care over this period. CONCLUSION: Socioeconomic factors play a significant role in explaining the observed variation in hospital discharge rates for musculoskeletal diseases. Models utilizing only physician practice variation to account for the population-based differences in discharge rates are overly simplistic. In order to ensure that vulnerable subsets of the population are not harmed by the introduction of cost-containment strategies based on simplistic models, more attention must be paid to the socioeconomic and epidemiologic factors related to hospital use.

Changing patterns of hospital use for patients with musculoskeletal disease in Michigan, 1980 to 1987.

Over the past 10 years there have been dramatic changes in health care financing in the United States, such as Medicare's Prospective Payment System for hospitalized Medicare beneficiaries, and in health services delivery, such as the growth in health maintenance organizations and other forms of managed care. These changes have occurred largely in response to payors' concerns about the rising cost of health care. A study of such changes in financing and delivery, and how specific groups of patients are affected is necessary so that the effects of these changes on patients' health can be determined. We examined the hospitalization rates for patients with musculoskeletal diseases in Michigan from 1980 through 1987. During this period, the overall age-adjusted hospitalization rates decreased 7.0% per year (p = 0.001). The decrease occurred less for surgical discharges (6.0% per year) than for medical discharges (8.6% per year) (p < 0.001). While these overall trends are of interest, they obscure disease-specific trends that vary significantly from both the overall, and the medical and surgical trends. For example, while surgical discharges, in general declined, procedures related to major joint and limb reattachment (DRG #209) increased at a rate of 6.3% per year. And while medical discharges in general decreased over this period, discharges for osteomyelitis increased 5.4% per year. The patterns of disease-specific trends offers insight into the possible causes for these changes. Finally, it is important to understand the epidemiology of hospital use to evaluate the effects of new medical care delivery and payment systems on the care of subsets of patients.

Measuring outcomes of hospital care using multiple risk-adjusted indexes.

Using existing data sources, we developed three risk-adjusted measures of hospital quality: the risk-adjusted mortality index (RAMI), the risk-adjusted readmissions index (RARI), and the risk-adjusted complication index (RACI). We describe the construction and validation of each of these indexes. After these measures were developed, we tested the relationships among the three indexes using a sample of 300 hospitals. Actual numbers of adverse events were observed for each hospital and compared to the number predicted by the RAMI, RARI, and RACI models. Then each hospital was ranked on each index. Our results showed that no relationship existed between a hospital's ranking on any one of these indexes and its ranking on the other two indexes. This result provides some evidence that no measure of quality should be used by itself to represent different aspects of the quality of hospital care. Adequate overall measures of hospital quality will need to include multiple measures in order to be credible and to reflect the complexity of hospital care. The findings suggest that consumers, payers, and policymakers cannot simply choose one hospitalwide measure, such as the mortality rate, to validly represent a hospital's performance: those hospitals with high rankings on their mortality rates do not necessarily rank high on their readmission rates or complication rates.

Use of community versus individual socioeconomic data in predicting variation in hospital use.

OBJECTIVES: (1) To examine the association of socioeconomic characteristics (SES) with hospitalization by age group, and when using measures of SES at the community as opposed to the individual level. (2) Thus, to support the inference that socioeconomic factors are important in the analysis of small area utilization data and address potential criticisms of this conclusion. DATA SOURCES: The 1989 Michigan Inpatient Database (MIDB), the 1990 U.S. Census, the 1989 Area Resource File (ARF), and the 1990 National Health Interview Survey (NHIS). STUDY DESIGN: A qualitative comparison of socioeconomic predictors of hospitalization in two cross-sectional analyses when using community as opposed to individual socioeconomic characteristics was done. DATA EXTRACTION. Hospitalizations (excluding delivery) were extracted by county from the MIDB and by individual from the NHIS. SES variables were extracted from the U.S. Census for communities and from the NHIS for individuals. Measures of employment for communities were from the ARF and information on health insurance and health status of individuals from the NHIS. PRINCIPAL FINDINGS: Both analyses show similar age-specific patterns for income and education. The effects were greatest in young adults, and diminished with increasing age. Accounting for multiple admissions did not change these conclusions. In the individual-level data the addition of variables representing health and insurance status substantially diminished the size of the coefficients for the socioeconomic variables. CONCLUSIONS: By comparison to parallel individual-level analyses, small area analyses with community-level SES characteristics appear to represent the effect of individual-level characteristics. They are also not substantially affected by the inability to track individuals with multiple readmissions across hospitals. We conclude that the impact of SES characteristics on hospitalization rates is consistent when measured by individual or community-level measures and varies substantially by age. These variables should be included in analyses of small area variation.

Patterns of surgical and nonsurgical hospital use in Michigan communities from 1980 through 1984.

Hospital discharge rates vary substantially among 60 communities in Michigan. (R2 = 90 percent and R2 = 85 percent of the systematic variance is explained by community effects for nonsurgical and surgical discharges, respectively.) The ranking of communities by discharge rates is stable over a five-year period (Spearman rho = 0.78 for nonsurgical discharges and 0.72 for surgical discharges). Surgical discharge rates decreased substantially (4 percent per year) over this time period, while nonsurgical rates showed no consistent pattern. Communities with exceptional discharge rates showed no substantial or significant regression toward the mean through the five-year study.

Comparing the hospitalizations of transfer and non-transfer patients in an academic medical center.

BACKGROUND: By accepting and caring for patients transferred from other institutions, academic medical centers have been able to develop comprehensive training and research programs. Whether academic institutions can continue to do this in the future is questionable. To the extent that transfer patients are more complex and severely ill than non-transfer patients, they are likely to consume more resources, and in managed care payment systems, they could place accepting hospitals in financial jeopardy. METHOD: Between July 1989 and December 1993, the internal medicine, surgery, and pediatrics services of the 880-bed University Hospital of the University of Michigan accepted 8,740 patients from other hospitals. The hospitalizations of these patients were compared with those of the 76,047 non-transfer patients on these services. The statistical methods used were Student's t-test, chi-square, Cochran-Mantel-Haenszel chi-square, and analysis of variance. RESULTS: The hospitalizations of the transfer patients were more complex and resource-use intensive. The transfer patients were more likely (p<.0000) to be length-of-stay outliers as defined by Medicare standards (28% vs 10%) and to suffer in-hospital death (9.4% vs 2.5%). After case-mix adjustment and exclusion of length-of-stay outliers, transfer patients on the three services (surgery, medicine, and pediatrics) remained in the hospital 1.62, 1.15, and 0.84 days longer (p<.0001) than non-transfer patients. Ancillary-service resource use was assessed using a relative-value-unit (RVU) scale based on direct-cost dollars. The transfer patients' case-mix-adjusted resource use exceeded that of the non-transfer patients by 1,155,850 and 957 RVUs for surgery, pediatrics, and medicine (p<.0001). Although the transfer patients were more likely to have Medicaid insurance, the differences in lengths of stay and use of ancillary services persisted throughout all insurance groups. Indeed, transfer status, compared with age, sex, and insurance status, was the best predictor of high resource use. CONCLUSION: The transfer patients stayed longer and consumed more hospital resources than did the non-transfer patients. Age, sex, case-mix, and insurance status did not account for these differences. To limit the financial liability that transfer patients pose, academic medical centers could be forced to abandon their traditional role of caring for such patients. The consequences of this possibility should be explored.

Variation in resource use within diagnosis-related groups: the severity issue.

Several authors have suggested that diagnosis-related groups (DRG's) make inadequate allowance for the severity of illness. Before modifications of DRG's are developed, the sources of within-group variation must be precisely defined; not all variation is attributable to the severity of illness. The limitations of the Uniform Hospital Discharge Data Set (UHDDS), of the International Classification of Diseases, Ninth Revision, Clinical Modification coding system and of the original rules of DRG construction must be evaluated and, if necessary, corrected before new approaches to groupings are considered. The most promising potential modifications of existing groups and weights are those that make use of the UHDDS, or of the UHDDS plus additional diagnoses and procedures. The addition of entirely new data elements to the discharge abstract and the pricing process should be considered only as a last resort.

Diagnosis-related group prospective payment. Effects on medical quality assurance.

The new system for hospital reimbursement, called "reimbursement by diagnosis-related group" (DRG), offers a unique opportunity for the development of novel approaches to quality assurance. Groups of medically similar patients with stable patterns of resource use have been defined. These groups form the basis of the new payment system. Patients whose care deviates from the norm of resource consumption for their group, so-called outliers, will need to be reviewed by the hospital's administrative and medical staff. Such outliers are likely to constitute different types of patients than those in their assigned group: (1) patients whose medical complexity precludes grouping because of limitations in the abstracted clinical data; (2) patients whose medical care deviated because of complications of therapy or inappropriate diagnostic and/or therapeutic interventions; (3) patients whose medical course is so unique that they would never fit any classification system. The DRG-based reimbursement system, then, will compel hospitals to review the care of these outliers. The rigorous examination of these patients and their care, although just a first step, should be a major boon to quality of care evaluations.

Changes in rates of unscheduled hospital readmissions and changes in efficiency following the introduction of the Medicare prospective payment system. An analysis using risk-adjusted data.

The purpose of this study was to analyze changes in rates of unscheduled readmissions and changes in technical efficiency following the introduction of the Medicare Prospective Payment System (PPS). We developed the Risk-Adjusted Readmissions Index (RARI), which allowed us to make comparisons in rates of unanticipated readmissions across hospitals and over time. Data envelopment analysis (DEA), a linear programming technique, was used to measure changes in technical efficiency by comparing the inputs used and the outputs produced across a cohort of hospitals, while adjusting for changes over time in case mix and case complexity. Rates of unscheduled readmissions and efficiency scores were computed for a sample of 245 hospitals for each year. Although both readmission rates and efficiency scores increased for most hospitals, there was no evidence that those hospitals that experienced the greatest increases in efficiency had the largest increases in their rates of unscheduled readmissions.

A critique of the Harvard Resource-Based Relative Value Scale.

Physician payment reform has assumed a prominent place in the national health policy debate. A key component in this debate is the Harvard Resource-Based Relative Value Scale (RBRVS). The Harvard research effort relied upon several necessary methodologic assumptions and compromises that must be understood to appreciate the RBRVS's strengths and weaknesses. For example, the Harvard group surveyed too few cases to cover the range of clinical practice in a specialty, had too little input in the selection of cases that were judged to be the same or equivalent between specialties, and used an unproven extrapolation methodology to assign final values for total work to non-surveyed physician services. This methodology led to a number of anomalies in the final RBRVS, such as values for comprehensive services for some specialties that were lower for new than for established patients, and total work values for many new patient office services that were lower for Internal Medicine than for Family Practice, a finding inconsistent with empiric evidence. The Harvard RBRVS represents a significant contribution that increases our understanding of physician practice. The system should not be viewed as a finished product. Further investigation and explanation of the assumptions and anomalies are needed to construct a system that reflects adequately the complexity in physician work.

Can Medicare prospective payment survive the ICD-9-CM disease classification system?

The Medicare prospective payment system represents a fundamental change in hospital payment. The diagnosis-related group (DRG) patient classification scheme serves as the modifier of payment for this system. The DRG definitions are, in turn, based on the International Classification of Disease, 9th Revision, Clinical Modification (ICD-9-CM). Deficiencies in the ICD-9-CM coding system directly affect the equity of the Medicare payment system. A review of the ICD-9-CM system identifies three principal problems: the inability of the system to reflect clinically important patient attributes adequately; the use of outcome, rather than approach, to code surgical procedures; and the blurring of clinical specificity by the adoption of certain coding rules. If these deficits in coding specificity are not corrected, it is unlikely that DRGs will adequately distinguish clinically unique types of patients. This inability to differentiate among patients threatens to undermine the equity of Medicare payments. Physicians must become more aware of disease coding and more involved in its development and implementation.

Variation in resource use within diagnosis-related groups. The effect of severity of illness and physician practice.

The diagnosis-related group (DRG)-based Medicare prospective payment system pays hospitals a fixed amount for the care of similar patients. The DRG definitions serve as the modifier of payment for Medicare patients. The dependence on these patient definitions raises many questions, among them the reason(s) for observed resource variability within a DRG. Various severity-of-illness measures have been shown to account for some of the resource variability noted within the DRGs. Most severity-of-illness studies to date, however, have not attempted to assess the effect of other known sources of resource variation, such as differing physician practice patterns. The authors examined the ability of severity of illness, as defined by disease staging, and physician practice variation to explain residual intra-DRG variability in length of stay. They demonstrate that physician practice variation accounts for more variance reduction than does severity of illness.

A cost benefit analysis of continued stay certification.

A large portion of the resources of the Professional Standards Review Organization Program have been directed toward the review of inpatients to determine their need for continued hospitalization. The primary goal of this review process is the containment of hospital costs through the elimination of unnecessary patient hospitalization. A cost benefit analysis of this review process shows that the potential financial savings accrued are unlikely to offset the costs associated with the review procedure.

Evaluating the care of general medicine inpatients: how good is implicit review?

OBJECTIVE: Peer review often consists of implicit evaluations by physician reviewers of the quality and appropriateness of care. This study evaluated the ability of implicit review to measure reliably various aspects of care on a general medicine inpatient service. DESIGN: Retrospective review of patients' charts, using structured implicit review, of a stratified random sample of consecutive admissions to a general medicine ward. SETTING: A university teaching hospital. PATIENTS: Twelve internists were trained in structured implicit review and reviewed 675 patient admissions (with 20% duplicate reviews for a total of 846 reviews). RESULTS: Although inter-rater reliabilities for assessments of overall quality of care and preventable deaths (kappa = 0.5) were adequate for aggregate comparisons (for example, comparing mean ratings on two hospital wards), they were inadequate for reliable evaluations of single patients using one or two reviewers. Reviewers' agreement about most focused quality problems (for example, timeliness of diagnostic evaluation and clinical readiness at time of discharge) and about the appropriateness of hospital ancillary resource use was poor (kappa < or = 0.2). For most focused implicit measures, bias due to specific reviewers who were systematically more harsh or lenient (particularly for evaluation of resource-use appropriateness) accounted for much of the variation in reviewers' assessments, but this was not a substantial problem for the measure of overall quality. Reviewers rarely reported being unable to evaluate the quality of care because of deficiencies in documentation in the patient's chart. CONCLUSION: For assessment of overall quality and preventable deaths of general medicine inpatients, implicit review by peers had moderate degrees of reliability, but for most other specific aspects of care, physician reviewers could not agree. Implicit review was particularly unreliable at evaluating the appropriateness of hospital resource use and the patient's readiness for discharge, two areas where this type of review is often used.

An integrated inpatient management model.

The academic health center has emerged as the cornerstone of the American health care system. To assess the vulnerability of the academic medical center to the new competitive forces that exist today, a prototype project has been developed that attempts to address the issue of competition in clinical activity, while at the same time enhancing the academic health center's education and research roles.

Variation in hospital admissions among small areas. A comparison of Maine and Michigan.

Analysis of age-adjusted hospital admission profiles among small geographic areas has shown marked variation in hospital admissions for both surgical and medical cases in areas ranging from Maine to Manitoba. Much of the work has been led by John Wennberg and has focused on rural areas. This study examines the degree of variation in hospital admissions in small areas in the state of Michigan to determine whether those diseases that demonstrated high variation in Maine also demonstrated the same degree of variation in Michigan. The data on the degree of variation in 111 modified diagnosis-related groups (M-DRGs) from the state of Maine were supplied by Dr. Wennberg. Using the same M-DRGs, we defined age-adjusted, population-based hospital admission rates for the lower peninsula of Michigan for 1980 among 60 previously defined hospital marked communities. The observed hospital discharge counts in each of the M-DRGs were compared to the expected counts in each of the 60 communities, where the expected count was based on an indirect age adjustment. Both the Maine and Michigan small area data were expressed by the M-DRG's systematic standard deviation in which random variation has been accounted for via a Poisson probability model. It was found that the systematic standard deviations of the M-DRGs in Maine and the M-DRGs in Michigan strongly correlated with a Spearman correlation coefficient of 0.71 (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparing the use of diagnostic tests in Canadian and US hospitals.

Although Americans pay much more for a day in the hospital than Canadians, we know little about whether inpatient physician practice patterns might explain some of this difference. The authors compared the utilization of all diagnostic imaging (plain radiographs, computed tomography (CT) and magnetic resonance imaging (MRI) scanning, ultrasound, nuclear medicine and vascular studies) and selected laboratory tests (hematology, basic biochemistry, and advanced biochemistry) for all patients discharged with selected medical and surgical diagnoses in 1990 and 1991 from four university hospitals and four community hospitals in Canada (n = 6,491) and the United States (n = 7,980). Overall, US medical patients received 22% more diagnostic tests than their Canadian counterparts (544.2 relative value units [RVUs] vs. 446.5 RVUs in Canada, P < 0.001), which was mainly the result of higher radiology use. Although mean radiology use was 40% higher in the United States (370.0 vs. 264.5 RVUs in Canada, P < 0.05), there was little difference in the use of laboratory tests between countries (174.2 vs. 182.4 RVUs in Canada, P = 0.3). Within radiology, only CT and MRI use differed significantly between countries (US patients received 119% more tests than Canadians). These findings were consistent after adjustments for age, gender, diagnosis-related group, and university status. Differences in test use between countries were mainly the result of more testing among the US elderly than counterparts in Canada. Among surgical patients, there was little difference between countries for radiology (76.3 vs. 67.3 RVUs in Canada, P < 0.05) and laboratory (83.6 vs. 91.4 RVUs in Canada, P < 0.05). Comparable inpatients admitted to US hospitals received more diagnostic tests than their Canadian counterparts even in hospitals with similar availability of technology. Differences between countries were larger for high-cost tests than for lower-cost tests. Much of the difference in test use is explained by more intensive use for the elderly in the United States.