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.

Utilization trends and risk factors for hospitalization in diabetes mellitus.

A population-based prevalence cohort of 1,111 residents of Rochester, Minnesota, who had diabetes mellitus on Jan. 1, 1975, was subjected to follow-up assessment for hospitalizations through Dec. 31, 1980. On the basis of these data, hospitalization rates were calculated for various clinical types of diabetes, and a risk factor analysis was done for non-insulin-dependent diabetes mellitus (NIDDM) to identify high-risk persons for subsequent intervention studies. The adjusted incidence density of hospitalization was 141.6 per 1,000 person-years for NIDDM and 331.3 per 1,000 person-years for insulin-dependent diabetes. Although the modeled clinical characteristics accounted for little variability in NIDDM-related hospitalization, age modified by the effect of gender was the strongest risk factor found (multivariate hazard ratios: 1.0 and 1.43, respectively, for male and female patients younger than 65 years old; 1.88 and 1.83, respectively, for male and female patients 65 years old or older); coronary heart disease, diabetic retinopathy, and persistent proteinuria were associated with a 50% increased risk. Although older patients with NIDDM (especially men) are at greatest risk for a first hospitalization, clinical factors alone seem inadequate to account for these hospitalizations. The effect of Medicare's prospective payment systems (PPS) was studied by using a data base for Olmsted County, Minnesota, to determine whether PPS decreased the rate of hospitalizations among patients with diabetes. Among Olmsted County residents 65 years of age or older, the adjusted rate of diabetes-associated hospitalizations decreased from 26.5 per 1,000 person-years in 1980 to 16.7 in 1985, whereas the adjusted rate of all other hospitalizations increased from 259.5 per 1,000 person-years to 261.9. Thus, PPS may have reduced hospitalization rates in elderly patients with diabetes.

Altering residency curriculum in response to a changing practice environment: use of the Mayo internal medicine residency alumni survey.

To elicit the opinions of practicing internists who had graduated from a single internal medicine residency program about the adequacy of their training and its relevance to their medical practice, we mailed a survey to 1,342 physicians who had spent at least 1 year in the Mayo internal medicine residency training program. Of this group, 703 alumni (52%) responded to the survey, 532 of whom were currently practicing internal medicine. Our detailed analysis was based on responses from these 532 and, for some aspects of evaluation, on the 121 general internists who had completed residency training after 1970. Of the respondents, 42% spent more than 80% of their time in general medicine, and 53% had at least some subspecialty practice; 55% were involved in teaching, 20% in some research, and 37% in various administrative duties. In 27%, all patient-care activities involved primary care, an increase from 18% in a 1979 survey and 9% in 1972. Of those who were subspecialists, 67% spent more than half their time in subspecialty practice. Of those who were trained after 1970, 90% were board certified. Most respondents thought that their training in the internal medicine subspecialties was adequate, that additional procedure training was needed in joint aspiration, line placement, and flexible sigmoidoscopy, and that many allied medical areas were important to their practice and necessitated additional training. Although virtually all respondents assessed their inpatient training as adequate, only 42% were fully satisfied with their outpatient training. Alumni surveys can be useful in restructuring a residency program to meet the needs of the trainees.

Economic outcome under Medicare prospective payment at a tertiary-care institution: the effects of demographic, clinical, and logistic factors on duration of hospital stay and part A charges for medical back problems (DRG 243).

We investigated the effects of prospectively identified factors on the duration of hospital stay and part A charges in 240 hospitalizations (of 230 patients) for the diagnosis-related group "medical back problems" (DRG 243) at a tertiary-care institution in 1985 to determine whether heterogeneity existed within this reimbursement category. We confirmed our initial postulates that nonosteoporotic fractures and neck problems, as well as hospitalizations primarily for myelography after outpatient neurologic evaluation, had considerably different economic outcomes and thus excluded these categories from further analysis. Statistical analysis (forward stepwise regression) of the remaining 132 patients who had "general medical back problems" showed that increasing age, associated osteoporosis, and therapeutic injections best explained variation in the natural logarithm of duration of stay (R2 = 0.16). Total number of diagnoses, spondylosis, associated osteoporosis, age, therapeutic injections, and performance of special procedures best explained the variation in the logarithm of part A charges (R2 = 0.29). The ability to identify factors within a specified category that affect the duration of hospitalization and part A charges jeopardizes the fairness of prospective payment, and we believe that DRG 243 should be adjusted for age, comorbidity, and readily identifiable clinical syndromes that have disparate economic consequences. Because of poorly substantiated efficacy and a significant association with longer hospital stays and higher part A charges, clinicians should review the use of therapeutic injections for medical back problems. Analysis of case-mix such as ours should be helpful in promoting efficient practice and ensuring the fairness of any reimbursement system.

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.

Acute cystitis: a prospective study of laboratory tests and duration of therapy.

The efficacy of single-dose therapy with trimethoprim-sulfamethoxazole (TMP-SMZ) and the cost-effectiveness of routine urinalyses and cultures were studied in a prospective randomized trial of 200 women who presented with symptoms of acute lower urinary tract infection. Without the physician's knowledge of the results of urinalysis or culture, the patients were randomly assigned to receive either a single dose or a 10-day multiple-dose course of TMP-SMZ and were followed up for 6 months. Of the 136 patients with positive urine cultures, 68 received single-dose therapy with TMP-SMZ--10 of whom had relapses--and 68 received multiple-dose therapy with TMP-SMZ--only 2 of whom had relapses (P less than 0.02). Fifteen patients in each treatment group experienced reinfection. Side effects of rash and vaginitis were more common in patients who received multiple-dose therapy, but they were mild and well tolerated. Of the 51 patients with urethral syndrome, 48 became asymptomatic after therapy. None of the following tests predicted treatment outcome: pretreatment urinalysis, urine culture or susceptibility testing, antibody-coated bacteria testing, or routine follow-up urinalyses or urine cultures. Empiric therapy with TMP-SMZ in selected women with symptoms of acute uncomplicated urinary tract infection seems practical, safe, and cost-efficient. Considerable savings can be achieved by reserving urinalyses and urine cultures for patients with persistent or recurrent symptoms. Higher cure rates can be expected in patients who receive a standard 10-day course of therapy with TMP-SMZ compared with those who receive single-dose therapy with TMP-SMZ.

A decline in carcinoma of the stomach. A diagnostic artifact?

During the past 50 years or more, a dramatic decline in the mortality from gastric carcinoma has been observed in virtually every country in the world, including the United States. Some investigators suspect that this decline is due to refinements in the diagnosis and classification of abdominal malignancies rather than being a true decline in the incidence of gastric cancer. Because the record system in Rochester, Minnesota, ensures the identification of virtually every patient in the local population with a serious illness, and the level of diagnosis is high, it seemed appropriate to study the incidence and long-term trends of gastric cancer in this community. Trend analysis for the period 1935 through 1979 revealed a consistent decline in the incidence of gastric carcinoma whether death certificates as the sole source of cases were included or not. Analysis of either all clinically confirmed or only tissue-confirmed cases revealed a statistically significant decrease in stomach carcinoma throughout the study period. These declines were observed even if only the more recent periods (1955 through 1979) were examined. The reasons for this finding remain obscure, but the study suggests that improvements in diagnostic accuracy alone cannot account for this remarkable downward trend in gastric malignancy.

Cardiac-catheterization and cardiac-surgical facilities: use, trends, and future requirements.

Cardiac catheterizations and cardiac operations were evaluated in the population of Olmsted County, Minnesota, from 1973 through 1980, and trends in this region were compared with nationwide trends based on data from several sources. The rates of coronary arteriography and coronary-artery bypass operations in Olmsted county have increased over time, but overall, the rates of catheterization and operation appeared to be leveling off. For the country as a whole, the data appear to show similar trends, but there are wide differences among regions in the rates of operation and catheterization. In 1980 40 per cent of hospitals with cardiac-catheterization laboratories and 55 per cent of those with facilities for open-heart surgery were doing fewer than the suggested minimum numbers of these procedures necessary to achieve optimum results. The data support the view that further growth in the number of cardiac centers should be avoided. We believe there is a need for continued evaluation of the use of cardiac services if quality is to be protected and costs controlled.

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.

Coronary heart disease in residents of Rochester, Minnesota, 1950-1975. I. Background and study design.

The unique medical data resource for the population of Rochester, Minnesota, is centered on the records of the Mayo Clinic and the Olmsted Medical and Surgical Group, which for several decades have provided nearly all medical care in this community. This resource has been utilized in a study of the incidence rates and secular trend in coronary heart disease for the period 1950-1975 among residents of Rochester. A total of 3,080 patients fulfilled the clinical and other criteria for inclusion in this study. The patients, classified by initial manifestation of coronary heart disease, consisted of 1,321 with myocardial infarction, 1,215 with angina pectoris, and 544 with sudden unexpected death. In this paper the background, clinical definitions, and study design are presented.

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.

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.

Trends in cardiac surgery. Five-year study of a defined population.

The total number and types of cardiac operations performed on residents of Olmsted County, Minnesota, from 1973 through 1977 were studied through the use of the medical-records linkage system at the Mayo Clinic. During this time, 213 patients underwent 216 operations. The rates of cardiac operations per 10,000 population increased from 4.1 in 1973 to 5.9 in 1977. Operations other than for coronary artery bypass showed no significant trends over time, and the average rate was 2.5 per year. The incidence of coronary artery bypass operations increased from 1.5 in 1973 to 4.0 in 1977. On the basis of the rates for open-heart operations and under conditions similar to those in this community, a population of approximately 380,000 persons less than 15 years of age would be required to ensure 75 cases requiring open-heart operations per year, and a population of approximately 230,000 persons more than 14 years of age would provide 200 adult open-heart cases per year. Thus total populations of approximately 1,380,000 and 310,000 of all ages would be required to meet these minimum standards for pediatric and adult open-heart operations.

Use of the cardiac-catheterization laboratory in a defined population.

We evaluated trends in the use of the cardiac-catheterization laboratory from 1973 through 1977 in a well-circumscribed population in southeastern Minnesota. A total of 346 patients (248 male and 98 female patients) underwent coronary arteriography, left ventriculography, or cardiac catheterization, and there were 369 visits to the catheterization laboratory. The total number of catheterization-laboratory visits per 10,000 population increased from 4.3 in 1973 to 11.5 in 1977. According to individual category, the rates for coronary arteriography increased more than fourfold during the five-year period, whereas the rates for cardiac catheterization period, whereas the rates for cardiac catheterization showed no substantial change. On the basis of the 1977 rate for all visits to the catheterization laboratory and under conditions similar to those in this community, a population of approximately 230,000 would be required to ensure use of a catheterization laboratory at the suggested minimum level of 300 adult examinations per year.

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.

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.