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Biomedical subjects

G Samsa

Publications and source records attributed to G Samsa.

At least 19 recordsLinked to original sources
PubMed2005

Quantitative myasthenia gravis score: assessment of responsiveness and longitudinal validity.

We prospectively tested the quantitative myasthenia gravis score (QMG) for responsiveness and longitudinal construct validity in 53 patients with myasthenia gravis. Index of responsiveness was high. Longitudinal construct validity was confirmed by the correlation between changes in QMG and manual muscle testing and by a difference in QMG changes across patients that were clinically unchanged, improved, or worse between two visits. Our results support QMG use for assessing clinical change in trials.

Adult↗
PubMed2000

Can continuous quality improvement be assessed using randomized trials? [see comment].

STUDY QUESTION: Continuous quality improvement (CQI) has been implemented at least to some degree in many health care settings, yet randomized controlled trials (RCTs) of CQI are rare. We ask whether, when, and how RCTs of CQI might be designed. STUDY DESIGN: We consider two applications of CQI: as a general philosophy of management and (by analogy with the use of conceptual models from the behavioral sciences) as a conceptual model for developing specific interventions. The example of warfarin therapy for stroke prevention among patients with atrial fibrillation is used throughout. PRINCIPAL FINDINGS: While it is impractical to use RCTs to study CQI as a general management philosophy, RCT methodology is appropriate for studying CQI as a conceptual model for generating interventions. RCTs of CQI might be considered when the process change under consideration is very large, its implications (e.g., in terms of cost, outcomes of care, etc.) are very great, and the best approach is uncertain. When designing RCTs of CQI, critical decisions include (1) the unit of randomization; (2) whether the focus is on CQI as a method for generating interventions or, instead, is on specific interventions in and of themselves; and (3) the flexibility available to local personnel to modify the intervention's operational details. CONCLUSIONS: RCTs of CQI as a conceptual model for generating interventions are feasible.

Anticoagulants↗
PubMed1999

Disability fingerprints: patterns of disability in spinal cord injury and multiple sclerosis differ.

BACKGROUND: Models for causation of functional disability differ as to whether different diseases lead to common expressions of disability versus producing unique "disability fingerprints." Multiple sclerosis (MS) and Spinal Cord Injury (SCI) both affect the spinal cord; however, their pathophysiologies differ (progressive vs. nonprogressive; multifocal vs. unifocal). METHODS: Patterns of disability were compared among veterans who reported in a national survey that they had MS (n = 1789) or SCI (n = 6361) as the sole cause of their spinal cord dysfunction. The study used self-reported information on disease duration, physical impairments, and self-care skills to compare the two samples for differences in disability overall and after stratification according to (a) disease duration, and (b) specific physical impairments. RESULTS: Patterns of disability differed significantly among persons with MS compared to SCI (p = .001). Differences in level of disability between the two samples remained statistically significant after stratification on disease duration. There were substantial, statistically significant differences between the two samples in the amount and kinds of physical impairment. However, differences in level of disability between the two conditions remained highly significant after stratifying on number of affected limbs (p = .003), amount of useful movement (p = .001), overall motor impairment (p = .003), amount of sensation (p = .001), impairment in memory and thinking (p = .001), and visual impairment (p = .001). CONCLUSIONS: This study shows differing diseases indeed have unique disability fingerprints, which remain unique after controlling for disease duration and for population-specific differences in physical impairment. These findings point out the need to explain the disablement process more fully.

Activities of Daily Living↗
PubMed1999

Determining clinically important differences in health status measures: a general approach with illustration to the Health Utilities Index Mark II.

The objective of this article was to describe and illustrate a comprehensive approach for estimating clinically important differences (CIDs) in health-related quality-of-life (HR-QOL). A literature review and pilot study were conducted to determine whether effect size-based benchmarks are consistent with CIDs obtained from other approaches. CIDs may be estimated based primarily upon effect sizes, supplemented by more traditional anchor-based methods of benchmarking (i.e. direct, cross-sectional or longitudinal approaches). A literature review of articles discussing CIDs provided comparative data on effect sizes for various chronic conditions. A pilot study was then conducted to estimate the minimum CID of the Health Utilities Index (HUI) Mark II, and to compare the observed between-group differences observed in a recent randomised trial of an acute stroke intervention with this benchmark. The use of standardised effect size benchmarks has a number of advantages-for example, effect sizes are efficient, widely accepted outside HR-QOL, and have well accepted benchmarks based upon external anchors. In addition, our literature review and pilot study suggest that effect size-based CID benchmarks are similar to those which would be obtained using more traditional methods. For most HR-QOL instruments, we do not know the changes in score which constitute CIDs of various magnitudes. This makes interpretation of HR-QOL results from clinical trials difficult, and having a benchmarking process which is relatively straightforward would be highly desirable.

Clinical Trials as Topic↗
PubMed1998

Developing a national registry of veterans with spinal cord dysfunction: experiences and implications.

We describe the development of a registry of veterans with spinal cord dysfunction who have been treated within the Department of Veterans Affairs health care facilities. The registry departs from the function and structure of traditional registries by a more extensive utilization of advances in computer technology; in particular, by its reliance upon computerized record linkage and by its association with a set of computer-based clinical management and reporting tools. We discuss some of the applications of the registry to research for persons with spinal cord dysfunction as well as implications that our experiences provide for developing other registries of persons with disabilities.

Humans↗
PubMed1997

Influence of projected complication rates on estimated appropriate use rates for carotid endarterectomy. Appropriateness Project Investigators. Academic Medical Center Consortium.

OBJECTIVE: To examine specifically the influence of estimated perioperative mortality and stroke rate on the assessment of appropriateness of carotid endarterectomy. DATA SOURCES/STUDY SETTING: An expert panel convened to rate the appropriateness of a variety of potential indications for carotid endarterectomy based on various rates of perioperative complications. We then applied these ratings to the charts of 1,160 randomly selected patients who had carotid endarterectomy in one of the 12 participating academic medical centers. STUDY DESIGN: An expert panel evaluated indications for carotid endarterectomy using the modified Delphi approach. Charts of patients who received surgery were abstracted, and clinical indications for the procedure as well as perioperative complications were recorded. To examine the impact of surgical risk assessment on the rates of appropriateness, three different definitions of risk strata for combined perioperative death or stroke were used: Definition A, low risk < 3 percent; Definition B, low risk < 5 percent; and Definition C, low risk < 7 percent. PRINCIPAL FINDINGS: Overall hospital-specific mortality ranged from 0 percent to 4.0 percent and major complications, defined as death, stroke, intracranial hemorrhage, or myocardial infarction, varied from 2.0 percent to 11.1 percent. Most patients (72 percent) had surgery for transient ischemic attack or stroke; 24 percent of patients were asymptomatic. Most patients (82 percent) had surgery on the side of a high-grade stenosis (70-99 percent). When the thresholds for operative risk were placed at the values defined by the expert panel (Definition A), only 33.5 percent of 1,160 procedures were classified as "appropriate." When the definition of low risk was shifted upward, the proportion of cases categorized as appropriate increased to 58 percent and 81.5 percent for Definitions B and C, respectively. CONCLUSIONS: Despite the high proportion of procedures performed for symptomatic patients with a high degree of ipsilateral extracranial carotid artery stenosis and generally low rates of surgical complications at the participating institutions, the overall rate of "appropriateness" using a perioperative complication rate of < 3 percent was low. However, the rate of "appropriateness" was extremely sensitive to judgments about a single clinical feature, surgical risk. These data show that before applying such "appropriateness" ratings, it is crucial to perform sensitivity analyses in order to assess the stability of the results. Results that are robust to moderate in variation in surgical risk provide a much sounder basis for policy making than those that are not.

Academic Medical Centers↗
PubMed1996

The relative importance of strength and balance in chair rise by functionally impaired older individuals.

OBJECTIVE: The ability to stand independently and safely from the seated position is essential for independent function. This investigation determined the relative contributions of measures of lower extremity strength and measures of balance control in explaining the performance characteristics of sitting-to-standing. Variables analyzed included those related to success of the activity (e.g., time to rise, lowest chair height) and to biomechanical characteristics of performance (e.g., how fast specific body segments moved). SETTING: Durham Veteran's Affairs Medical Center motion analysis laboratory. DESIGN: Cross-sectional correlational study. PARTICIPANTS: Fifty-eight men and women aged 66 to 96 (mean = 77) with functional limitations. MEASUREMENTS: Predictor variables were lower extremity strength (isometric) and balance (functional reach and sway). The outcome variable, chair rise performance, was quantified by: lowest successful chair height (chairs at 33 to 58 cm); time to rise; maximum hip flexion angular velocity; and the maximum horizontal and vertical velocities of the motion of the body center of mass (COM). Covariates were lower extremity range of motion and sensory status. RESULTS: With bivariate analysis, lower extremity strength demonstrated relationships with the lowest chair height (r = -0.639) and maximum vertical velocity of the COM (r = .389); functional reach was associated with three variables (lowest chair height r = .374; time to rise r = .297; and maximum horizontal velocity of the COM r = .251). Using a multivariate regression analysis (including lower extremity strength, functional reach, sensory loss, and lower extremity range of motion), the model accounted for 47% of the variance in lowest chair height; lower extremity strength was the only significant predictor (P < .001). The model also accounted for 20% of the variance in maximum horizontal velocity of the COM; lower extremity strength was a significant predictor (P = .006). CONCLUSIONS: Lower extremity strength and balance control both play a role in performance of chair rise; lower extremity strength is the stronger predictor of success for functionally impaired older adults.

Aged↗
PubMed1996

Inpatient costs of specific cerebrovascular events at five academic medical centers.

We estimated the hospital costs for patients with different cerebrovascular events and applied patient and administrative variables to explain the variance of the cost estimates with particular attention to the relationship between patient age and cost. The study sample was drawn from an administrative data set of all hospital discharges from five academic medical centers for the 1992 calendar year. Using International Classification of Diseases (ICD-9-CM) primary diagnosis codes, cases were classified into cerebrovascular subgroups: subarachnoid hemorrhage (SAH), intracerebral hemorrhage (ICH), ischemic cerebral infarction (ICI), and transient ischemic attack (TIA). The ICD-9-driven data file was supplemented with billing data containing inpatient charges reported in UB-82 format. Costs were imputed by applying Medicare charge-to-cost ratios and regional wage adjustments to the billing data. We estimated relationships between inpatient costs and a number of demographic and administrative variables. A statistically significant difference was found between cerebrovascular subgroups for both the mean cost per discharge (p<0.01) and the mean cost of an inpatient day (p<0.01). The mean cost per discharge for each subgroup was as follows: SAH, $39,994 (n=218); ICH, $21,535 (n=258); ICI, $9,882 (n=908); TIA, $4,653 (n=303). Likewise, the mean cost per inpatient day was as follows: SAH, $2,215; ICH, $1,396; ICI, $1,036; TIA, $1,117. Length of stay as a measure of resource use was strongly predictive of inpatient cost, explaining 72 to 82% of the variation in cost. Demographic variables (i.e., age, gender, race, insurance status), however, revealed virtually no predictive power, accounting for less than 10% of the variance in each of the four subgroups. There are substantial differences in the patient-level cost of hospital services for stroke-related events. After controlling for the type of cerebrovascular event, basic demographic variables and insurance status (including Medicare) contribute little to the total cost of inpatient care. More important factor include stroke severity, social factors, and clinical practice variations.

Academic Medical Centers↗
PubMed1995

Physician attitudes about anticoagulation for nonvalvular atrial fibrillation in the elderly.

BACKGROUND: Our goal was to determine whether patient age affects a physician's reported likelihood of using anticoagulant therapy or the intensity of anticoagulant therapy for patients with nonvalvular atrial fibrillation. METHODS: We surveyed a nationwide sample of 1189 randomly selected office-based practitioners in three strata: primary care (geriatrics, internal medicine, family practice, and general practice), cardiology, and neurology. A vignette-based questionnaire was used to measure attitudes and beliefs regarding anticoagulation risks and effectiveness, barriers to anticoagulation in clinical practice, and likelihood of using anticoagulation and target intensity of anticoagulation at three patient ages (55, 65, and 75 years) for four clinical scenarios (chronic non-valvular atrial fibrillation with mild left atrial enlargement, intermittent or paroxysmal atrial fibrillation, recent-onset atrial fibrillation, and atrial fibrillation with recent [3 months] embolic stroke). RESULTS: The overall response rate was 38%. The mean likelihoods of using anticoagulation for the three ages were unequal (P < .0001) for each scenario. Most physicians were "very" or "somewhat" likely to use anticoagulant therapy for a 65-year-old with left atrial enlargement (71%), intermittent or paryoxysmal atrial fibrillation (68%), recent-onset atrial fibrillation (86%), or embolic stroke (96%). Fewer physicians were likely to use anticoagulant therapy for a 75-year-old with left atrial enlargement (63%), intermittent or paroxysmal atrial fibrillation (56%), recent-onset atrial fibrillation (80%), or embolic stroke (93%). Among physicians equally likely to use anticoagulation for 65- and 75-year-old patients, intensity of anticoagulant therapy (target international normalized ratio or prothrombin time ratio) was lower (P < .04) for the 75-year-old. CONCLUSION: Anticoagulant therapy may be less often and less intensively used for elderly patients with nonvalvular atrial fibrillation.

Aged↗
PubMed1994

Lack of association between patients' measured burden of disease and risk for hospital readmission.

Identifying patients at increased risk for hospital readmission is important for clinicians, health policy-makers, hospital administrators, and researchers. We used a retrospective case-control design to compare the clinimetric properties of five validated indices that measure a patient's disease burden. The study was conducted on a random sample of patients discharged from the general medicine service at the Durham Department of Veterans Affairs Medical Center. Trained observers (two research assistants, one nurse, and two physicians) blinded to readmission status abstracted the required data elements from the medical record for three indices (Charlson, Kaplan-Feinstein, Index of Coexistent Disease). The hospital's computer provided data elements for two indices (Smith, adapted Charlson). Indices varied in the time required to complete, the ability to capture individual heterogeneity, and inter-observer variability. However, none of the indices discriminated among patients who did and those who did not have 6-month hospital readmissions. Factors other than summary scores derived from these indices should be used to identify patients at high risk for readmission.

Aged↗
PubMed1994

Predicting falls: the role of mobility and nonphysical factors.

OBJECTIVE: Our purpose was to test a four-domain predictive model of recurrent falls developed for this study. In this model, limited mobility is considered a necessary but not sufficient element in risk of recurrent falls. Three other domains, attitudinal, social, and environmental, are proposed to influence fall risk only in persons with impaired mobility. DESIGN: Prospective cohort study. SETTING: Veterans Affairs Ambulatory Care Service serving rural and urban central North Carolina. SUBJECTS: Male Veterans aged 70 or older (n = 306) were monitored prospectively for falls. At baseline, 159 screened as high-risk mobility status and 147 as low-risk mobility status. MEASUREMENTS: The primary outcome was recurrent falls. The mobility screen used for risk assignment defined immobile as unable to sit without support for 60 seconds, mobile and stable as meeting criteria for normal ambulation and stair climbing, and mobile but unstable as those who met neither of the above criteria. The high-risk subjects were further assessed in their homes for mobility in more detail, attitude toward risk, social supports, and environmental status. Other data included demographics, functional status, diagnoses, and medications. RESULTS: Recurrent falls occurred in 37 (23.3%) high-risk subjects and seven (4.8%) low-risk subjects (relative risk = 4.8, confidence interval 2.5 to 9.6, P < 0.001). Within the high-risk group, the probability of recurrent falls was significantly affected by degree of impaired mobility (P < 0.001), attitude toward risk (P = 0.005), and environment score (P = 0.03). CONCLUSIONS: A simple mobility screen can identify elders at increased risk for recurrent falls. Risk within this group is further modified by risk-taking behavior and environment.

Accidental Falls↗
PubMed1993

Cost effectiveness analysis of early zidovudine treatment of HIV infected patients.

OBJECTIVE--To compare cost effectiveness of early and later treatment with zidovudine for patients infected with HIV. DESIGN--Markov chain analysis of cost effectiveness based on results of use of health care and efficacy from a trial of zidovudine treatment. SETTING--Seven Veterans Affairs medical centres in the United States. SUBJECTS--338 patients with symptomatic HIV infection and a lymphocyte count of 200 x 10(6) to 500 x 10(6) CD4 cells/l. INTERVENTIONS--Zidovudine 1500 mg/day started either at recruitment to the trial or when CD4 cell count fell below 200 x 10(6)/l. MAIN OUTCOME MEASURES--Health care costs and rates of disease progression between six clinical states of HIV infection. RESULTS--Patients given early treatment with zidovudine remained without AIDS for an extra two months at a cost of $10,750 for each extra month without AIDS (at 1991 costs). Cost effectiveness ratio was most sensitive to the cost of zidovudine and to the quality of life of patients receiving early treatment. At treatment of 500 mg/day the cost effectiveness ratio for early treatment was $5432 for each extra month without AIDS. Patients given early treatment experienced more side effects, and if their quality of life was devalued by 8% compared with patients treated later the two treatments were equivalent in terms of quality adjusted months of life without AIDS. CONCLUSIONS--Early treatment with zidovudine is expensive and is very sensitive to the cost of zidovudine and to potential reductions in quality of life of patients who experience side effects. Doctors should reconsider early treatment with zidovudine for patients who experience side effects that substantially compromise their quality of life.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Teaching cardiovascular examination skills: results from a randomized controlled trial.

PURPOSE: To evaluate the effectiveness of a teaching program designed to improve interns' cardiovascular examination skills. PARTICIPANTS: All 56 interns rotating on a mandatory 4-week inpatient cardiology service during 1 academic year (July 1989-June 1990). METHODS: We randomly assigned interns to receive either an eight-session physical diagnosis course ("teaching group") taught on the cardiology-patient simulator ("Harvey") or to receive no supplemental teaching ("control group"). Before and immediately after the teaching or control period, the interns were evaluated on three preprogrammed simulations (mitral regurgitation, MR; mitral stenosis, MS; aortic regurgitation, AR). Immediately after the control or the intervention period, the interns also evaluated patient volunteers. RESULTS: There were no baseline differences in the interns' ability to correctly identify the disease simulations. Both the intervention and the control interns showed similar, moderate improvement in their diagnostic ability on the simulator. The intervention interns improved on MR from 42% correct to 54% correct; on MS from 8% correct to 23% correct; and on AR from 46% correct to 58% correct. The intervention and the control interns performed similarly on patient volunteers: for MR, 20% correct versus 31%; for AR, 29% correct versus 33%; and for aortic sclerosis, 64% correct versus 33%, respectively. CONCLUSIONS: The interns had difficulty correctly identifying three valvular heart disease simulations before and after an educational intervention employing a cardiovascular-patient simulator. At no time did the proportion of correct responses exceed 64%. Our teaching intervention during internship was either of insufficient intensity or of insufficient duration to produce significant improvement in cardiovascular diagnostic skills.

Cardiology↗
PubMed1992

Criteria for the use of Sartwell's incubation period model to study chronic diseases with uncertain etiology.

This study explores the conditions under which Sartwell's incubation period model may be appropriate for identifying a primary time period of etiologic risk for chronic diseases with uncertain etiology. The investigation begins with a description of the evolution of the application of Sartwell's model from infectious to chronic diseases. The model's underlying assumptions and some concerns about its use in the chronic disease context are specified. These concerns are addressed by data simulations and analyses of empirical data from the Connecticut Tumor Registry and the Radiation Effects Research Foundation. The results indicate that the distribution of age at diagnosis (i.e. onset) for chronic diseases is not necessarily lognormal. However, the representativeness of age distribution of the case series can affect the distribution's form; hence, it is important to determine the extent of "missing" cases, particularly those lost through truncation. Moreover, a lognormal age distribution may occur with both prenatal and age-related postnatal exposures. These findings suggest that only under certain conditions will Sartwell's model be useful in the study of chronic diseases of uncertain etiology, and indicate some caveats for interpretation of the results.

Chronic Disease↗
PubMed1992

Predictors of two-year post-hospitalization mortality among elderly veterans in a study evaluating a geriatric consultation team.

OBJECTIVE: To determine predictors of 2-year post-hospitalization mortality in a cohort of elderly hospitalized patients originally assembled to assess the impact of a Geriatric Consultation Team (GCT). DESIGN: Two-year follow-up of an inception cohort. SETTING: University-affiliated tertiary care VA Medical Center. PATIENTS: One hundred sixty-seven veterans age 75 or older discharged following hospitalization on medical, surgical, or psychiatry services but not intensive care units. INTERVENTION: None specifically studied here though cohort was previously part of randomized control trial of a Geriatric Consultation Team. MEASUREMENT: Mortality during 2 years of post-hospitalization follow-up. RESULTS: Two-year post-hospitalization mortality was 28 percent with no difference between the original GCT and control groups. For the entire sample, age, mental status, admission or discharge ADLs (but not change in ADL status), number of admission problems, number of discharge diagnoses, and discharge site were significant predictors of mortality in univariate analysis. Only discharge ADLs and discharge site remained significant in multivariate analysis. CONCLUSION: Measures of ADLs during hospitalization are stronger predictors of mortality following hospitalization than disease diagnoses. Impaired ADLs and placement other than at home are significant predictors of mortality, suggesting that the decision for nursing home placement contains other independently predictive information within it and/or that the subsequent nursing home period produces excess mortality. As had been indicated in short-term follow-up, there was no survival advantage for the Geriatric Consultation Group.

Activities of Daily Living↗
PubMed1992

Factors associated with veterans' decisions about living wills.

Most states have adopted legislation that allows patients to designate by advance directives the type of health care they would like to receive if they should become incompetent while suffering from a terminal illness. The living will is one of the most common of these legal instruments. Unlike most studies that have examined very sick or hospitalized patients' preferences regarding life-sustaining treatments, our study explores the concerns of 70 ambulatory veterans from a general medical clinic regarding living wills. Before the interview, 43% of patients reported never having heard of living wills. At interview, 4% of the patients had a living will, 33% intended to sign a living will but had not done so (INTEND), 54% were undecided about living wills (UNDECIDED), and 9% did not want a living will. Compared with UNDECIDED patients, all other patients did not differ in the use of health care services during the previous year or in diagnoses. INTEND patients, however, were significantly more likely to be white, to express poorer health status, to know someone with a living will, and to have previously discussed the topic. UNDECIDED patients were more likely than INTEND patients to report that religious beliefs about living wills affected their decision. Virtually all (91%) of the respondents believed that signing a living will would not affect their treatment. These data suggest that many patients may not know that they can have a living will and that discussions with those who already have a living will may be helpful in educational programs designed to promote informed patient decision-making.

Aged↗
PubMed1990

Atypical metaplasia and incidence of bronchogenic carcinoma.

The prognostic implication of atypical squamous metaplasia of the respiratory tract has been uncertain, especially for mild atypia. The relation between degree of severity of atypical metaplasia as detected by sputum cytology and incidence of bronchogenic carcinoma was assessed among 14,414 men aged 45 years or older who smoked one or more packs of cigarettes per day. Trial participants underwent sputum cytologic evaluations every 4 months for an average of 7.4 years as part of the Cooperative Early Lung Cancer Detection Program of the National Cancer Institute and were followed for the development of lung cancer between 1971 and 1983 at three institutions: The Johns Hopkins University, the Memorial Sloan-Kettering Cancer Center, and the Mayo Clinic. Analysis with logistic regression controlling for age, race, occupational exposures to lung carcinogens, average number of cytology records per year, and smoking habits revealed that the estimate of the relative rate (RR) of developing bronchogenic carcinoma was greater among men who had mild atypia as compared with men who had negative cytology readings, but there were marked differences among institutions (RR = 1.1, 95% confidence interval (Cl) 0.8-1.5 at The Johns Hopkins University; RR = 1.6, 95% Cl 1.1-2.5 at the Memorial Sloan-Kettering Cancer Center; and RR = 2.5, 95% Cl 1.6-4.0 at the Mayo Clinic). Results suggest that mild atypia as detected by cytologic evaluation of sputum is an indicator of a modest elevation in risk of bronchogenic carcinoma.

Carcinoma, Bronchogenic↗