A consensus has developed on the need for a major revision of physician reimbursement in the Medicare program. The Physician Payment Review Commission has recommended to Congress a series of far-reaching changes in the payment system, based on the development of a fee schedule using a Resource Based Relative Value System (RBRVS). This article explores the rationale for the recommendations and the probable impact on Medicare beneficiaries and their physicians if the changes are enacted. Special consideration is given to unique aspects of geriatric medicine, including comprehensive geriatric assessment.

Fee Schedules↗

PubMed1988

Evaluation of laboratory methods for the classification of oxacillin-resistant and oxacillin-susceptible Staphylococcus aureus.

The purpose of this study was to examine the efficacy of the oxacillin disk diffusion test and the methicillin and oxacillin agar screen tests as predictors of oxacillin resistance as defined by the reference broth microdilution method. A total of 444 clinical isolates of Staphylococcus aureus collected from individual patients over a four-year period were tested by (1) the oxacillin disk diffusion test, with particular attention to the presence of fine growth of a resistant subpopulation within the zone of inhibition (Ox Grow interpretive criteria); (2) the agar screen method using agar plates with 4% NaCl and either 6 mg/L oxacillin or 10 mg/L methicillin; and (3) the oxacillin and methicillin broth microdilution test methods with 2% NaCl supplementation. Overall, 62 (14%) isolates were resistant and 382 (86%) isolates were susceptible to oxacillin with the use of the reference broth microdilution system. The results indicate that the disk diffusion test with the use of the Ox Grow criteria had a high sensitivity (94%) and negative predictive value (98%) but a low specificity (67%) and positive predictive value (32%) when compared with the reference broth dilution test. Similarly, the agar screen tests had a high sensitivity (95-97%) and negative predictive values (99%) but low specificity (64-74%) and positive predictive values (30-37%). These data indicate that the agar screen tests and the oxacillin disk test with the use of the Ox Grow interpretive criteria may be useful as screening tests for detecting resistance to the penicillinase-resistant penicillins but that all resistant isolates should be confirmed by the reference broth dilution method because of the large number of false-resistant screening test results.

Bacteriological Techniques↗

PubMed1988

Implications of acquired oxacillin resistance in the management and control of Staphylococcus aureus infections.

Refinements in testing for resistance to penicillinase-resistant penicillins (PRP) in Staphylococcus aureus have resulted in confusion in classifying isolates as PRP susceptible or resistant. Specifically, a group of organisms has been identified that produce large amounts of beta-lactamase and appear borderline resistant. These organisms have been called "occult resistant" or "acquired oxacillin-resistant" S. aureus (AORSA). A retrospective study was conducted to evaluate the implication of this in vitro phenomenon in managing patients with AORSA infections. Among 134 patients with S. aureus infections, 89 were infected with oxacillin-susceptible S. aureus (OSSA), 26 with AORSA, and 19 with oxacillin-resistant S. aureus (ORSA). There were no significant differences in outcomes when OSSA and AORSA infections were treated with PRP (chi 2MH = .990; P = .32). These results do not suppor the contention that AORSA infections should be managed differently from OSSA infections. Identifying AORSA may not be helpful in guiding antimicrobial therapy or predicting the outcome of infections with AORSA.

Adult↗

PubMed1988

Competition and the quality of care: the importance of information.

Whether competitive mechanisms sacrifice quality in their efforts to control the costs of health care will depend on the ability of consumers to make informed choices of providers and the ability of providers to make informed decisions in using services in diagnosis and treatment. The availability of relevant information on the quality of providers and the effectiveness of services to both consumers and providers will determine the effects of competition on quality. We describe the types of information needed, how it can be developed, and the roles that government and the private sector must play in developing and disseminating this information.

Communication↗

PubMed1987

Variation in methicillin-resistant Staphylococcus aureus occurrence by geographic location and hospital characteristics.

A survey of 162 Veterans Administration Medical Center (VAMC) laboratories performing antimicrobial susceptibility testing was performed to determine variation in reported rates of methicillin-resistant Staphylococcus aureus (MRSA) isolation by geographic location and hospital characteristics. Of the 162 VAMC laboratories surveyed, 136 (84%) provided usable data. The percentage of S aureus isolates reported as resistant to methicillin ranged from 0% to 52% with a mean value of 10% among the 136 survey respondents. MRSA were isolated in every VA Medical District and 96% of all respondent laboratories reported isolating at least one MRSA isolate during the preceding year. These data are considered an underestimate of the time MRSA rate in the VA system due to the fact that many laboratories failed to follow key methodologic guidelines for optimal detection of MRSA. A positive correlation was found between MRSA isolation rate and several measures of hospital size and activity including total beds, total admissions, and total antimicrobial susceptibility tests performed. Geographic clustering of MRSA isolation was observed with distinct areas of very high and very low percentages of S aureus isolates reported as MRSA. The data suggest that the geographic distribution of MRSA within the VA system should be monitored closely for evidence of spread from areas with high-MRSA rates to areas of mid- or low-MRSA rates. Evidence of increased MRSA isolation within these areas may necessitate increased caution in patient referral and transfer patterns within the VA system.

Cross Infection↗

PubMed1987

Variation from standards in Staphylococcus aureus susceptibility testing.

In an effort to assess the degree of methodologic variation and adherence to current guidelines for detection of methicillin-resistant Staphylococcus aureus (MRSA), the authors surveyed the susceptibility testing practices of all 162 microbiology laboratories in the Veterans Administration (VA) system. Completed questionnaires were returned by 136 (84%) of the laboratories. Overall, 96 (71%) laboratories used disk diffusion testing, 54 (40%) used manual broth dilution, and 36 (26%) used an automated method. The percentage of MRSA detected ranged from 0 to 52%, with a mean of 10%. In general, fewer than 60% of laboratories followed the current susceptibility testing guidelines for key methodologic variables such as inoculum preparation, duration of incubation, and medium supplementation. Failure to adhere to these guidelines may result in suboptimal detection of MRSA.

Culture Media↗

PubMed1987

Use of the appropriateness evaluation protocol for estimating the incremental costs associated with nosocomial infections.

Existing methods for estimating additional days of hospital stay due to nosocomial infections (NI) have a number of documented limitations. An alternative method described in this paper uses the Appropriateness Evaluation Protocol (AEP) to determine whether each day of acute inpatient care is appropriate based on the need for care of the NI, original cause of hospitalization (OC), or combined NI-OC requirements. Using this method to identify specific days of hospitalization due to Staphylococcus aureus nosocomial infection, we find: 1) length of stay is increased for only a minority of patients (38%); 2) an average of 20 additional days of stay occurred for patients with 1 or more days attributed to NI; and 3) an average of 52% of length of stay of patients with 1 or more days attributed to NI can be attributed to the NI. Application of the AEP-based method is a useful alternative for identifying additional days of stay due to NI.

Costs and Cost Analysis↗

PubMed1986

Changing physician payment for Medicare patients. Projected effects on the quality of care.

Congress and the Reagan Administration, in an effort to "contain" costs, are considering changes in the way physicians are paid when they care for Medicare patients. By examining the effects on quality of care of several alternative ways physicians might be paid, including modified fee for service, physician diagnosis-related groups and capitation through health maintenance organizations, we can predict the kinds of effects on quality of care most likely to occur and the kinds of patients most likely to be affected. Under each of the payment alternatives, poorer and sicker patients are at greatest risk for reduced access to care and quality of care. These findings underline the need for rigorous experiments to assess the effects of changes in physician payment on quality of care and the need for monitoring and assurance of quality in a new payment system.

Humans↗

PubMed1982

Inhibition by bacitracin of rat adipocyte plasma membrane degradation of 125I-insulin is associated with an increase in plasma membrane bound insulin and a potentiation of glucose oxidation by adipocytes.

The present study demonstrated that at physiological concentrations of insulin bacitracin inhibited the degradation of specifically bound insulin by enzymes located in the rat adipocyte plasma membrane. Bacitracin increased the amount of intact insulin specifically bound to the plasma membrane and potentiated the stimulation of adipocyte glucose oxidation by submaximal concentrations of the hormone. In contrast to agents such as chloroquine, which inhibit lysosomal degradation of internalized insulin, bacitracin was shown by two approaches to inhibit a degradative process localized to the adipocyte plasma membrane. Cyanide and 2,4-dinitrophenol, agents which inhibit energy requiring endocytosis, had no effect on the bacitracin inhibition of cellular degradation of 125I-insulin. Bacitracin directly inhibited 125I-insulin degradation by isolated plasma membranes at similar concentrations and to a similar extent as found with cells. The degradative process inhibited by bacitracin accounted for the majority of cellular degradation of the hormone. The increased 125I-insulin bound to adipocytes was shown to be intact by gel chromatographic analysis and was localized to the plasma membrane by direct and indirect approaches. Bacitracin increased 125I-insulin specifically bound to isolated plasma membranes as early as 2 min. The 125I-insulin bound to adipocytes in the presence of bacitracin was completely dissociable by the addition of 8 microM unlabeled insulin whereas a significant portion of 125I-insulin bound to chloroquine-treated cells could not be dissociated. Bacitracin slowed dissociation of 125I-insulin from the cells. Bacitracin increased the 125I-insulin binding to cells in the presence and absence of cyanide and 2,4-dinitrophenol. Bacitracin potentiated the stimulation of adipocyte glucose oxidation at submaximal concentrations of insulin.

Adipose Tissue↗

PubMed1982

Evaluation of three minicolumn procedures for measuring hemoglobin A1.

We have evaluated three commercially available column-chromatographic methods (Isolab, Helena, and Bio-Rad) for the determination of "fast" hemoglobin (HbA1). All three methods correlated with HbA1c measurements by "high-performance" liquid chromatography for 121 samples from diabetic patients, with the Isolab method showing the highest correlation (r = 0.921). The Isolab and Helena methods gave results that were linear with proportions of HbA1 as great as 30%; results by the Bio-Rad method were slightly nonlinear at values greater than 15%. The Isolab method showed better within- and between-assay precision (CV) than the other two methods and was considered the simplest to perform by each of four different technologists. We recommend use of the Isolab method over the other two tested and believe that this procedure will be valuable for monitoring long-term glycemic control in diabetic patients.

Analysis of Variance↗

PubMed1981

Adaptation of fat cells to exercise: response of glucose uptake and oxidation to insulin.

The purpose of this study was to determine whether exercise training alters the sensitivity and responsiveness to insulin of glucose uptake and oxidation in fat cells. Female rats were exercised by swimming 6 h/day, 5 days/wk for 12 wk. The swimmers' fat cells were smaller than those of sedentary controls of the same age and similar body weight. A larger amount of insulin was specifically bound by fat cells of the trained rats because of an increase in the number of insulin receptors. The rates of 2-deoxyglucose uptake and of glucose oxidation were higher in fat cells of trained compared with sedentary rats at all insulin concentrations. A maximal insulin stimulus resulted in rates of sugar uptake and oxidation that were about sixfold higher in trained than in sedentary rats' fat cells. This greater responsiveness to insulin could not be explained by the increase in insulin binding but appears to be mediated by adaptation/s) at a step(s) beyond the binding of insulin to its receptors. Our findings suggest that fat cells of exercise-trained animals are adapted for rapid replenishment of energy stores.

Adaptation, Physiological↗

PubMed1980

Lysosomal degradation of receptor-bound 125I-labeled insulin by rat adipocytes: its characterization and dissociation from the short-term biologic effects of insulin.

In this study we used chloroquine to characterize the interalization and lysosomal degradation of receptor-bound 125I-insulin by rat adipocytes and to determine the role of lysosomal processing of insulin in the short-term biologic effects of the hormone. Chloroquine inhibited the degradation of 125I-insulin bound to adipocytes by both association and disslociation experiments. In the former experiments, chloroquine caused a time- and concentration-dependent increase in specifically bound insulin owing to an increase in intact insulin and a decrease in degradation products, as determined by trichloroacetic acid precipitability and gel chromatographic analysis of material extracted from the cells. In the dissociation experiments, 50 microM chloroquine decreased the rate of degradation by two third, as reflected in the release of degradation to or degraded by isolated plasma membranes, on the degradation of 125I-insulin by proteases in the incubation medium, or on the endocytotic uptake of receptor-bound insulin. Quantitative electron miroscopy, using monomeric ferritin-insulin, showed 50 microM chloroquine doubled the number of lysosomal structures containing ferritin. These findings are consistent with an inhibition by chloroquine of lysosomal degradation of internalized receptor-bound insulin. Chloroquine, at these same concentrations, had no effect on the ability of insulin to stimulate glucose transport and oxidation or to inhibit epinephrine-stimulated lipolysis. In these studies, we show that lysosomal degradation of internalized receptor-bound insulin is not necessary for insulin to cause short-term biologic effects in the adipocyte.

Adipose Tissue↗

PubMed1979

Development and regression of exercise-induced cardiac hypertrophy in rats.

Adult female rats were exercised by daily swimming. All the increase in heart weight induced by the exercise occurred within 14 days and averaged 30%. The half times of the increases in heart weight and total protein content were about 4.5 days, whereas that of cytochrome c, which was used as a mitochondrial marker, was 6.5 days. The total amounts of DNA and of hydroxyproline in the heart, which were used to evaluate the degree of connective tissue hyperplasia, increased only slightly (8% and 10%, respectively). Other animals were subjected to the same swimming program for 21 days. Groups of rats were killed at various time intervals after stopping exercise. Heart weight, total protein content, and total cytochrome c content decreased rapidly initially, with 60% of the total regression of hypertrophy occurring during the first week. Thereafter, heart weight fell more gradually toward the sedentary control value. The hydroxyproline content of the heart, which was increased 10%, did not decrease during the regression of the hypertrophy.

Animals↗