Contribution of a measure of disease complexity (COMPLEX) to prediction of outcome and charges among hospitalized patients.

Attention has been focused on the need to adjust hospital reimbursement and outcomes of hospital care for level of illness. Extant measures of disease severity, however, fail to consider the contribution of disease complexity. We developed an easily retrievable measure of disease complexity (COMPLEX) by modifying an existing severity system, computerized Disease Staging. The contribution of COMPLEX (the number of body systems affected with a Disease Staging score of 2 or more) to the prediction of outcome was assessed in two studies: (1) a population-based analysis of readmission and mortality after hospitalization and (2) an analysis of hospital charges among patients who were in an intensive-care unit. The amount of variation in mortality explained by factors included in the Health Care Financing Administration model was significantly improved when COMPLEX was added to the model (adjusted odds ratio per body system, 1.83; 95% confidence interval, 1.61 to 2.08). A significant association was also observed between COMPLEX score and hospital readmission after adjustment for age, sex, case-mix, and disease severity (adjusted odds ratio, 1.31; 95% confidence interval, 1.20 to 1.44). When COMPLEX was added to case-mix and disease severity in a model for predicting hospital charges, the percentage of variation in hospital charges explained by the model increased from 25% to 38%. These findings demonstrate the important contribution of disease complexity to the analysis of outcome of medical care and utilization of resources. Outcome or reimbursement models that do not incorporate disease complexity may negatively affect institutions with a high proportion of patients who have complex conditions.

Hospital and posthospital survival in patients mechanically ventilated for more than 29 days.

Experience with prolonged mechanical ventilation has improved over recent years. Retrospective analysis of the records of 104 patients older than 16 years of age who were mechanically ventilated for more than 29 days over a 29-month period from May 1986 to October 1988 revealed the following findings. The mean patient age was 66.3 +/- 15.7 years (SD). The mean number of in-hospital ventilator days was 59.9 +/- 36.7 days (range, 29 to 247 days). The mean number of days of oral or nasal endotracheal intubation prior to tracheostomy (96 patients) was 21.5 +/- 14.2 days. The mean length of hospital stay for the 104 patients was 79.9 +/- 45.4 days. The majority of the 104 patients (82.6 percent) were surgical patients. Nine patients left the hospital receiving extended mechanical ventilation. Mortality was highest in multiple organ system failure and lowest among the trauma patients. The total days of mechanical ventilation did not appear to be related to mortality if patients older than 16 years survived for seven days. Postdischarge survival of the 53 of 60 patients who survived and whom we were able to contact was 67 percent at one year and 56 percent at three years.

Trends in elderly hospitalization and readmission rates for a geographically defined population: pre- and post-prospective payment.

To address the paucity of patient-level data regarding the effectiveness of Medicare's prospective payment system (PPS), we conducted a population-based study of inpatient hospitalizations among individually identified elderly residents of Olmsted County, Minnesota, 1970-1987. A 4.3% increase in total days of care/1000 population from 2,652/1,000 in 1970 to 2,766/1,000 in 1980 was followed by a 9.8% decline from 1980 to 1987 (2,495/1,000). The decline was due primarily to a 13.4% decrease in mean length stay (9.7 days in 1980 to 8.4 days in 1987). The number of hospitalizations/1,000 Olmsted County elderly in 1980 was already below 1987 U.S. figures and did not exhibit the decline evidenced nationally between 1980 and 1987. A 4.6% decline in the proportion of county residents age 65-74 years who were hospitalized (174/1,000 in 1980 to 166/1,000 in 1987) was offset by an 8.3% increase for persons age greater than or equal to 75 (252/1,000 to 273/1,000) and by a 5.7% increase in the number of hospitalizations per individual hospitalized for persons age 65-74 years (1.34 to 1.42). Using a time-dependent Cox model, which adjusted for differences in patients characteristics between years, there was a significantly higher risk of readmission within 14 days in 1987 vs 1980 (hazard ratio (HR) = 1.33, 95% confidence interval (CI) = 1.05-1.70). The difference between years was no longer evident at 30 or 60 days (HR = 0.84, 95% CI = 0.63-1.11 between 15 and 30 days; HR = 1.12, 95% CI = 0.84-1.49 between 31 and 60 days). This study suggests that initial effects of PPS on utilization may be temporary and that more research is needed to appreciate the impact of cost-containment on patient outcome.

Assessment of prediction of mortality by using the APACHE II scoring system in intensive-care units;.

Some investigators have suggested that information on quality of care in intensive-care units (ICUs) may be inferred from mortality rates. Specifically, the ratio of actual to predicted hospital mortality (A/P) has been proposed as a valid measure for comparing ICU outcomes when predicted mortality has been derived from data collected during the first 24 hours of ICU therapy with use of a severity scoring tool, APACHE II (acute physiology and chronic health evaluation). We present a comparison of mortality ratios (A/P) in four ICUs under common management, in two hospitals within a single institution. Significant differences in A/P were detected for nonoperative patients (0.99 versus 0.67;P = 0.014) between the two hospitals. This variation was traced to uneven representation of a subset of patients who had chronic health problems related to diseases that necessitated admission to the hematology-oncology or hepatology service. No differences in A/P were seen between the two hospitals for operative patients or for nonoperative patients on services other than hematology-oncology or hepatology. Thus, differences in A/P detected by using the APACHE II system not only may reside in operational factors within the ICU organization but also may be related to weaknesses in the APACHE II model to measure factors intrinsic to the disease process in some patients. We suggest that case-mix must be examined in detail before concluding that differences in A/P are caused by differences in quality of care.

Disposition at discharge and 60-day mortality among elderly people following shorter hospital stays: a population-based comparison.

This study examines whether shorter hospital stays following the introduction of Medicare's Prospective Payment System have been accompanied by increased mortality or an increased rate of discharge to nursing homes. An examination of hospitalizations for all elderly residents of Olmsted County, MN (N = 5,854) for 1980, 1985, and 1987 demonstrates significant increases in 60-day mortality and nursing home transfers after this system began. These increases, however, are largely explained by differences in risk factors other than length of stay, such as patient age, gender, disease severity, and complexity.

Impact of increased physician supply on use of health services: a longitudinal analysis in rural Minnesota.

Prevalence studies of the use of ambulatory health care services have consistently reported relatively lower demand for services in rural areas. Such studies have implied that low use rates may be fixed characteristics of rural populations and may be resistant to the influence of manipulable variables such as supply of physicians. This longitudinal study suggests that use rates are in fact significantly changed after improvement of manpower resources, but that the effects are limited to the vicinity of new practice locations.

Is percutaneous coronary angioplasty less expensive than bypass surgery?

Percutaneous transluminal coronary angioplasty is widely considered to be an acceptable and less expensive alternative to bypass surgery in carefully selected patients. We compared expenditures related to cardiac care for 79 unselected patients undergoing coronary angioplasty with expenditures for 89 unselected patients undergoing elective coronary bypass surgery without a previous attempt at angioplasty. All the patients had single-vessel disease. The mean aggregate one-year monetary outlay was 15 per cent lower in the angioplasty group than in the bypass-surgery group. A major component of the expense of angioplasty was the treatment of restenosis in the 33 per cent of patients in this group in whom this late complication occurred. We conclude that percutaneous transluminal coronary angioplasty has potential for reducing expenditures for cardiac revascularization and that a further reduction may be obtainable when the rates of restenosis are improved.

Hospital use in a fee-for-service system.

The population of Olmsted County, Minnesota, receives care virtually exclusively from two fee-for-service group practices: the Mayo Clinic and the Olmsted Medical and Surgical Group. Study of the use of acute-care hospital services by this population in 1976 reveals that the hospital discharge rate per 1,000 population, adjusted for age and sex, was 30% less than the national rate; the age-sex-adjusted rate of hospital days per 1,000 population was 38% less than the national rate. Analysis by length of stay, type of hospital service, frequency of selected diagnoses and surgical procedures, and certain demographic and economic characteristics did not explain the differences from national use rates. These rates are comparable, after age and sex adjustment, with those in larger prepaid group practices. The analysis suggests that the organization of medical care may have an important influence on hospital use.

The Mayo three-community hypertension control program. V. Cost-effectiveness of intervention.

This paper compares the costs of a categorical clinic model for community hypertension intervention with the costs of two less resource-intensive hypertension programs. Three categories of costs are measured for each program: program costs, patient costs, and time costs. Total costs are expressed in terms of costs per hypertensive patient controlled under each program. When adjusted for differences in hypertension prevalence and screening costs in the three community programs, the cost-effectiveness of the categorical clinic model is questionable. These results suggest that careful analyses of the categorical clinic model in other communities should be conducted before public resources are committed to the establishment of such models on a widespread basis.

The Mayo three-community hypertension control program. IV. Five-year outcomes of intervention in entire communities.

Beginning in 1974, the Mayo three-community hypertension control program initiated intervention studies in three southeastern Minnesota communities. This paper reports on the blood pressure outcomes 5 years after the inception of graduated programs involving public and professional education, detection, referral, and, in one community, systematic stepped care. Despite differences in local physician-population ratios and organization of medical care, perseverant long-term reductions of blood pressure were noted in all communities. However, the mean diastolic pressures were lower and the number of individuals at goal (diastolic blood pressure 90 mm Hg or less) was higher in the community offering categorical care. These data suggest that while programmatic efforts to control hypertension resulted in favorable blood pressure declines, the outcomes were particularly impressive in the community with a categorical hypertension clinic model offering systematic management of hypertensive patients.

Use of medical services and satisfaction with ambulatory care among a rural Minnesota population.

Patient satisfaction with health care services and the use of ambulatory care in rural southeastern Minnesota were surveyed before and after physician manpower was increased. This report is confined to the findings in 1974, before the three local practicing physicians were joined by two additional physicians. The physician to population ratio at the time of the initial survey was 1 to 6,200 in 1974 and 1 to 2,500 with the additional physicians in 1975.In this area the population of 12,400 centered around the town of Zumbrota. A total of 1,332 persons completed questionnaires, and 796 filled out a second questionnaire concerning patient satisfaction with health care. The scores on 40 items formed 18 satisfaction indices.Use of health services was lower than in the National Health Survey of 1969; the mean number of visits per year in Zumbrota was 3.3 compared with 4.3 for the national sample. The volume of use in the Zumbrota region was low, particularly among adults. Use of services was not significantly related to the education, occupation and income of the residents. About 10 percent of the population accounted for half of the total number of visits.Only a few of the 18 patient satisfaction indices were related to the respondent's income and occupation, but 5 were related to educational level. Satisfaction with health care services was generally higher in this rural population than among the people in four urban areas that were surveyed using the same satisfaction indices.The question raised by the findings in this survey-are rural areas in general as deprived and unsatisfied with health care as the literature suggests-remains unsettled. Changes over time in use and patient satisfaction are being assessed in the resurvey to seek possible explanations of the low utilization and high degree of patient satisfaction in this area.

Public health education and the control of hypertension in the United States.

In recent years, national and regional health education programs have sought to increase public awareness concerning the risks of asymptomatic hypertensive disease. Such programs have fostered community screening and encouraged long-term care. As a result of these intensive educational efforts, larger numbers of persons with hypertension are now aware of blood pressure elevations and the pool of treated hypertensive patients has grown in number. Recently observed declines in mortality due to cardiovascular disorders in the United States may relate to efforts committed to the control of hypertension. Although a wide range of alternative explanations for these major declines are possible, changes in risk factors and, more pertinently, effective large-scale management of hypertension are plausible explanations for these salutary secular trends.

The Mayo Three-Community Hypertension Control Program. I. Design and initial screening results.

The Mayo Three-Community Hypertension Control Program implemented graduated programs for the control of high blood pressure in three rural southeastern Minnesota communities, beginning in 1974. Prevalence of hypertension (when defined as diastolic blood pressure, at initial screening, of 95 mm Hg or more) was similar to that found for comparable groups by age and sex in the United States generally, but an atypically high frequency of known but untreated hypertension was found. Programs of public and professional information, systematic household screening, continuing professional education (two communities), and a new community hypertension clinic (one community) were initiated, and plans were made to evaluate the programs simultaneously by means of total rescreening of persons found to be hypertensive initially. The present report describes in detail the design of the program and the results of initial screening in relation to findings in other populations at the time. Subsequent reports assess the impact of each program on its target community and of a community hypertension clinic within the one setting where this component of a model program was established.

The Mayo Three-Community Hypertension Control Program. III. Outcome in a community-based hypertension clinic.

As part of a broader community program to evaluate approaches to hypertension control, a Community Hypertension Clinic, staffed by two nurse practitioners, was set up in a rural community. Hypertensive persons were identified either by an initial central blood pressure screening or by a subsequent home screening. Slightly more than half of the hypertensive patients at initial screening, or 256 persons, elected to go to the Community Hypertension Clinic for second-stage screening, whereas the remainder elected to see their physicians or to do neither. After secondary screening at the Clinic, 120 patients eventually came under care and were managed by the nurse practitioners. After 2 years of follow-up, 57% of the Clinic patients had office-recorded diastolic blood pressures of less than 90 mm Hg. The Community Hypertension Clinic dropout rate was only 5% after 30 months of operation, for participants whose duration of follow-up ranged from 12 to 27 months (median 16 months), when a repeat home blood pressure screening examination was performed. Comparison of outcomes was thus possible between persons who attended the Community Hypertension Clinic and those who were referred to their physicians' offices. Persons with more severe hypertension most often elected to go to the Clinic, whereas patients with milder degrees of hypertension tended to go to their private physicians for follow-up or failed to make the recommended second-stage screening contact altogether. Greater declines in blood pressure were observed in the Clinic group.