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Biomedical subjects

S Greenfield

Publications and source records attributed to S Greenfield.

At least 19 recordsLinked to original sources
PubMed1992

Differential actions of acetylcholinesterase on the soma and dendrites of dopaminergic substantia nigra neurons in vitro.

In the substantia nigra, acetylcholinesterase (AChE) has non-cholinergic action on dopaminergic neurons. The subset of neurons particularly sensitive to AChE are characterized by functionally active apical dendrites extending into the pars reticulata and generating a powerful calcium conductance. This study thus attempted to establish directly the importance of these dendrites regarding the action of AChE. Segregation of the pars compacta from the pars reticulata did not affect the AChE-induced hyperpolarization on this sub-set of dopaminergic neurons. However, the ionic basis of the hyperpolarization was related to the integrity of the neurons: AChE caused an opening of potassium channels in intact cells. On the other hand when the pars reticulata containing apical dendrites was removed, an action of AChE involving the closure of calcium/sodium channels was revealed. The results demonstrate that the net effect of AChE need not be related to any particular segment of the dopaminergic neurons, whereas the nature of the mechanism underlying that effect depends on the presence, or otherwise, of the apical dendrites.

Acetylcholinesterase↗
PubMed1992

Differences in the mix of patients among medical specialties and systems of care. Results from the medical outcomes study.

OBJECTIVE: To determine differences in the mix of patients among medical specialties and among organizational systems of care. STUDY DESIGN: Cross-sectional analysis of 20,158 adults (greater than or equal to 18 years of age) who visited providers' offices during 9-day screening periods in 1986. Patient and physician information was obtained by self-administered, standardized questionnaires. SETTING: Offices of 349 physicians practicing family medicine, internal medicine, endocrinology, and cardiology within health maintenance organizations, large multispecialty groups, and solo or small single-specialty group practices in three major US cities. OUTCOME MEASURES: Demographic characteristics, prevalence of chronic disease, disease-specific severity of illness, and functional status and well-being. RESULTS: Among patients with selected physician-reported chronic illnesses (diabetes, hypertension, recent myocardial infarction, or congestive heart failure), increasing levels of severity were associated with decreasing levels of functional status and well-being and with increased hospitalizations, more physician visits, and higher numbers of prescription drugs. Compared with patients of general internists, patients of cardiologists were older (56 vs 47 years, P less than .01), had worse functional status and well-being scores (P less than .01), and carried more chronic diagnoses (mean 1.32 vs 1.02, P less than .01); patients of family practitioners were younger (40 vs 47 years, P less than .01) and more functional (P less than .01), carried fewer chronic diagnoses (0.70 vs 1.02, P less than .01), and (among diabetic patients only) had lower disease-specific severity scores (2.06 vs 2.30 on a five-point scale, P less than .01). Compared with patients in health maintenance organizations, patients visiting solo practitioners under fee-for-service payment were older (50 vs 45 years, P less than .01) and sicker (had worse physical functioning) and had a higher mean number of chronic diagnoses (1.10 vs 0.93, P less than .01). CONCLUSION: Patient mix is related to utilization and differs significantly across medical specialties and systems of care. These differences must be taken into account when interpreting variations in utilization and outcomes across specialties and systems, and when considering alternative policies for payment.

Activities of Daily Living↗
PubMed1992

Variations in resource utilization among medical specialties and systems of care. Results from the medical outcomes study.

OBJECTIVE: To examine whether specialty and system of care exert independent effects on resource utilization. STUDY DESIGN: Cross-sectional analysis of just over 20,000 patients (greater than or equal to 18 years of age) who visited providers' offices during 9-day periods in 1986. Patient- and physician-provided information was obtained by self-administered questionnaires. SETTING: Offices of 349 physicians practicing family medicine, internal medicine, endocrinology, and cardiology within health maintenance organizations, large multispecialty groups, and solo practices or small single-specialty group practices in three major US cities. OUTCOME MEASURES: Indicators of the intensity of resource utilization were examined among four medical specialties (family practice, general internal medicine, cardiology, and endocrinology) and five systems of care (health maintenance organization, multispecialty group-fee-for-service, multispecialty group-prepaid; solo practice and single-specialty group-fee-for-service, and solo practice and single-specialty group-prepaid) before and after controlling for the mix of patients seen in these offices. The indicators of resource utilization were hospitalizations, annual office visits, prescription drugs, and common tests and procedures, with rates estimated on both a per-visit and per-year basis. RESULTS: Variation in patient mix was a major determinant of the large variations in resource use. However, increased utilization was also independently related to specialty (cardiology and endocrinology), fee-for-service payment plan, and solo and single-specialty group practice arrangements. After adjusting for patient mix, solo practice/single-specialty groups-fee-for-service had 41% more hospitalizations than health maintenance organizations. General internists had utilization rates somewhat greater than family physicians on some indicators. CONCLUSION: Although variations in patient mix should be a major determinant of variations in resource use, the independent effects of specialty training, payment system, and practice organization on utilization rates need further explication. The 2- and 4-year outcomes now being analyzed will provide information critical to interpretation of the variations reported herein.

Adult↗
PubMed1992

Reactive fibromyalgia syndrome.

OBJECTIVE: To determine the frequency of a precipitating event occurring prior to the onset of fibromyalgia syndrome, in a consecutive series of patients. Outcome in patients in whom there was a causative factor was compared with that in patients with primary fibromyalgia. METHODS: Records of patients presenting over a 4-year period who fulfilled criteria for fibromyalgia were reviewed, and patients were classified as having reactive fibromyalgia if a specific event prior to the onset of illness could be identified. Outcome features, including employment status and disability compensation, were compared in patients with reactive fibromyalgia versus those with primary fibromyalgia. RESULTS: Twenty-nine of 127 patients (23%) with a primary rheumatologic diagnosis of fibromyalgia reported having trauma, surgery, or a medical illness before the onset of fibromyalgia, and were classified as having reactive fibromyalgia. Patients in this group were more disabled than those with primary fibromyalgia, resulting in loss of employment in 70%, disability compensation in 34%, and reduced physical activity in 45%. CONCLUSION: The development of fibromyalgia after a precipitating event may represent the onset of a prolonged and disabling pain syndrome with considerable social and economic implications.

Employment↗
PubMed1992

Ambulatory testing for capitation and fee-for-service patients in the same practice setting: relationship to outcomes.

Previous studies of the impact of varying reimbursement incentives on physician behavior have not explored the simultaneous implications for patients' health outcomes. Using a single group of physicians who provided care for hypertensive patients with either capitation (N = 99) or fee-for-service (N = 66) health insurance plans, physicians' test-ordering behavior and patients' subsequent health outcomes were examined. After controlling for patients' age, severity of hypertension, and level of comorbidity, it was found that patients with capitation health insurance had fewer laboratory tests and lower overall charges than the fee-for-service patients, with no clinical or statistically significant differences in 1-year health outcomes, specifically blood pressure control. The study concludes that capitation can result in reduction in charges associated with management of hypertension, without apparent compromise in proximate health outcomes.

Adult↗
PubMed1992

Recent developments and future issues in the use of health status assessment measures in clinical settings.

This paper provides a broad overview of the assessment of health status in clinical practice in three parts. Yesterday: The nation has undergone a paradigm shift in health-related thinking. The former paradigm emphasized only disease; the new emphasizes health, functioning, well-being, and disease. Measures of health and disease have evolved to reflect the new paradigm. Many are designed for clinical settings, based on measurement science, and are relatively brief. These newer measures have been used to document the natural history of disease, evaluate treatment effectiveness, and improve clinical case management. Today: Two barriers block full-scale use in clinical settings. The first barrier involves the meaning and interpretation of health status scores. Patients' scores are influenced by several types of patient mix variables and the timing of measurements. Interpretation is enhanced by valid normative data displaying the variability in health status among homogenous patient groups. The second barrier is utilization and mainstreaming. It involves all of the issues associated with changing the day-to-day behavior of clinicians and providers' routine processes to facilitate routine use of health status measures in clinical settings. Tomorrow: In the next decade, the nation will attempt to overhaul the health care system. As it does so, it will struggle with many issues: 1) clarifying the true aim of health care; 2) standardizing measures of health across patients, providers, and settings to evaluate benefit; 3) establishing cause and effect among structural-input factors, care delivery processes, and health outcomes valued by society; and 4) determining if and when cost containment actions have adverse effects on health outcomes. In this context, the importance of interpreting change in health status has a central role.

Activities of Daily Living↗
PubMed1991

Variations in length of stay and outcomes for six medical and surgical conditions in Massachusetts and California.

OBJECTIVES: --To determine the extent to which interinstitutional variations in length of stay are explained by differences in patient characteristics and to determine whether patients in hospitals with shorter lengths of stay had worse outcomes. DESIGN: --We reviewed patients' medical records and surveyed patients between 3 and 12 months after hospital discharge using a questionnaire. SETTING: --Six teaching hospitals in California and Massachusetts. PATIENTS: --A cohort of 2484 selected patients who had been hospitalized for acute myocardial infarction or to rule out acute myocardial infarction, coronary artery bypass graft surgery, total hip replacement, cholecystectomy, or transurethral prostatectomy. Between 73% and 84% of the patients with each condition completed a follow-up questionnaire. OUTCOME MEASURES: --In-hospital complications, deaths, length of stay, functional status after hospital discharge, readmission, and patient satisfaction with hospital care were analyzed. RESULTS: --Significant interinstitutional differences in length of stay were noted for all conditions except rule-out acute myocardial infarction. Statistical adjustment for case-mix differences accounted for most of the interinstitutional differences in length of stay for total hip replacement but explained little of the differences in the other conditions. When we controlled statistically for other predictors, length of stay did not have a significant impact on deaths, functional status after hospital discharge, the probability of readmission, or patient satisfaction with hospital care. CONCLUSION: --More research is needed to determine the medical practices that are related to variations in lengths of stay. Routinely available outcome data may help preserve quality in the face of efforts to decrease costs by effecting more standardized practices of care.

Adult↗
PubMed1991

Patterns of care related to age of men with prostate cancer.

A chart review study was done of 242 Stages A2 to D1 cancer patients to determine whether the age of patients with prostate cancer influenced their physicians' management strategies. Ten hospitals of varying size, medical-school affiliation, and patient socioeconomic status participated in this study. Patterns of prostate cancer care were examined using sets of branching logic standards in the form of criteria maps. A chart-based comorbidity index was used to control for the effect of coexisting diseases on cancer management. Regression models indicated that patient age affected the intensity of both the diagnostic evaluation and therapy, even after controlling for independent factors such as comorbid disease and individual hospital differences. Patients aged 75 years and older had significantly less intensive clinical staging workups and use of surgical and radiation therapies compared with patients aged 65 to 74 years and patients aged 50 to 64 years. In conjunction with similar results noted in studies of elderly patients with other malignancies, these results suggest that age bias is likely to be widespread. Physicians need to consider life expectancy, the ability of the patient to tolerate diagnostic procedures and therapies, and the quality of life in making treatment decisions.

Age Factors↗
PubMed1991

Assessing quality of life after surgery.

Researchers and clinicians increasingly are recognizing the importance of assessing a wide range of outcomes when evaluating the efficacy of medical therapies or procedures. We developed and evaluated a set of self-report scales that assessed both generic and condition-specific aspects of health-related quality of life before and after surgery. We report data from a study of patients having one of four types of surgery at six teaching hospitals in California and Massachusetts. The four surgical conditions studied were: total hip replacement, transurethral prostatectomy, cholecystectomy, and coronary artery bypass graft surgery. All the outcome scales, except for those assessing cognitive functioning and fatigue, had internal consistencies greater than 0.70. The pattern of correlations between the scales and other measures of health status are similar to those reported in other studies and provide evidence of their construct validity. The scales also appeared to be sensitive to differences between presurgical and postsurgical health-related quality of life. The results suggest that the scales used were easy to administer, reliable, valid, and offered important information about outcomes of surgery that is not provided by more traditional clinical indicators.

Activities of Daily Living↗
PubMed1991

How the medical comorbidity of depressed patients differs across health care settings: results from the Medical Outcomes Study.

OBJECTIVE: Although depression is one of the most common problems of medical and psychiatric outpatients, it has not been clear whether the extent of medical comorbidity among depressed patients varies across major types of clinical settings in which depressed patients receive care--especially by type of treating clinician (general medical versus mental health specialty) or type of payment for services (prepaid versus fee-for-service). METHODS: The authors examined these issues using data on 1,152 adult outpatients with current depressive symptoms and a lifetime history of unipolar depressive disorder who received care in one of three health care delivery systems in three U.S. sites. RESULTS: Depressed patients had a similarly high prevalence (64.9%-71.0%) of any of eight common chronic medical conditions whether they were seen in the general medical or specialty mental health sector; however, those visiting medical clinicians had a significantly higher prevalence of the two most common chronic medical conditions, hypertension and arthritis. Among depressed patients with hypertension, those visiting the general medical sector were more likely to be taking antihypertensive medication than were those visiting the mental health specialty sector. Type of payment (prepaid versus fee-for-service) was unrelated to either prevalence or severity of comorbid medical conditions, suggesting that the typical depressed patient in all types of practices studied had medical comorbidity. CONCLUSIONS: These data suggest that clinicians in all health care settings must be prepared to encounter chronic medical conditions and complaints in the depressed patients who visit them.

Adult↗
PubMed1991

[Evaluation of quality of care in the United States].

Quality assessment in the USA has been undertaken during the past twenty years by different institutions sponsored by the Congress, the government and professional associations. The evaluation tools which were developed reflect both the diversity of the American medical scene fashions in health care management. They evolved from norms to incentives, but each step in this evolution left its marks in the form of regulations, financial incentives and traditions.

Consensus Statements as Topic↗
PubMed1978

Efficiency and cost of primary care by nurses and physician assistants.

We conducted a prospective study in a prepaid primary-care practice (health-maintenance organization) of a system in which nurses and physician assistants used protocols, and compared the efficiency and costs of this "new-health-practitioner" protocol system to a physician-only nonprotocol system. In five months, we studied 472 patients with any of four common acute complaints--respiratory infections, urinary and vaginal infections, headache, and abdominal pain; a subset of 203 patients was randomly allocated between the two systems. In the new-health-practitioner system physician time per patient was reduced by 92 per cent, from 11.8 to 0.9 minutes, and average visit costs--including practitioner time and charges for laboratory tests and medications--were 20 per cent less (P = 0.01). We conclude that this protocol system saves physician time and reduces costs.

Abdomen↗