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Biomedical subjects

A J Hartz

Publications and source records attributed to A J Hartz.

At least 19 recordsLinked to original sources
PubMed2004

Randomized controlled trial of Siberian ginseng for chronic fatigue.

BACKGROUND: Chronic fatigue greatly affects quality of life and is a common reason for consulting a physician. Since conventional therapy is often of limited help, fatigued patients may use herbal treatments. This randomized controlled trial evaluated the effectiveness of Siberian ginseng. METHOD: Subjects were recruited from advertisements in Iowa (82%) and members of chronic fatigue syndrome support groups (18%). Potential subjects were required to have substantial fatigue > or = 6 months with no identifiable cause. The mean change in a fatigue measure was compared for placebo and Siberian ginseng at 1 and 2 months. Comparisons were for all subjects and for subjects with characteristics previously identified in the literature as important for categorizing chronic fatigue. RESULTS: Ninety-six subjects were randomized to treatment groups, and 76 provided information at 2 months of follow-up. Fatigue among subjects assigned to either placebo or Siberian ginseng was substantially reduced during the study, but differences between treatment groups were not statistically significant in the full sample. Fatigue severity and duration had a statistically significant interaction with response to Siberian ginseng at the P < 0.05 level. Treatment was effective at 2 months for 45 subjects with less severe fatigue (P = 0.04 unadjusted for multiple comparisons) and for 41 subjects with fatigue for > or = 5 years (P = 0.09 unadjusted for multiple comparisons). CONCLUSION: Overall efficacy was not demonstrated. However, the findings of possible efficacy for patients with moderate fatigue suggests that further research may be of value.

Adult↗
PubMed2000

A comparison of observational studies and randomized, controlled trials.

BACKGROUND: For many years it has been claimed that observational studies find stronger treatment effects than randomized, controlled trials. We compared the results of observational studies with those of randomized, controlled trials. METHODS: We searched the Abridged Index Medicus and Cochrane data bases to identify observational studies reported between 1985 and 1998 that compared two or more treatments or interventions for the same condition. We then searched the Medline and Cochrane data bases to identify all the randomized, controlled trials and observational studies comparing the same treatments for these conditions. For each treatment, the magnitudes of the effects in the various observational studies were combined by the Mantel-Haenszel or weighted analysis-of-variance procedure and then compared with the combined magnitude of the effects in the randomized, controlled trials that evaluated the same treatment. RESULTS: There were 136 reports about 19 diverse treatments, such as calcium-channel-blocker therapy for coronary artery disease, appendectomy, and interventions for subfertility. In most cases, the estimates of the treatment effects from observational studies and randomized, controlled trials were similar. In only 2 of the 19 analyses of treatment effects did the combined magnitude of the effect in observational studies lie outside the 95 percent confidence interval for the combined magnitude in the randomized, controlled trials. CONCLUSIONS: We found little evidence that estimates of treatment effects in observational studies reported after 1984 are either consistently larger than or qualitatively different from those obtained in randomized, controlled trials.

Bone Density↗
PubMed2000

Trends during 25 years of coronary artery bypass operation at St. Luke's Medical Center in Milwaukee, Wisconsin.

BACKGROUND: Most studies of changes in coronary artery bypass graft (CABG) operations are from major academic institutions. The present study evaluated changes in CABG operations since 1968 in a community hospital. METHODS: The data were from the St. Luke's Medical Center Cardiovascular Data Registry in Milwaukee, Wisconsin. Mortality rates, risk factors, overall patient risk, and surgical procedures were compared from 1968 to 1994. RESULTS: There was a dramatic decrease in 30-day mortality rates from 1968 to 1972. After 1976, mortality rates increased because of higher risk patients, but the mortality rate, adjusted for patient risk, continued to decline. Both internal mammary arteries and sequential grafts were widely used by 1972, followed by a decline in use until 1980, and then a steep increase in use from 1980 to the present. CONCLUSIONS: This study provided evidence from a community hospital that the skills of the surgical teams improved first dramatically then gradually. The pattern of adapting new surgical techniques suggested that these techniques were critically evaluated for several years after they were introduced.

Aged↗
PubMed2000

Community characteristics associated with elder abuse.

OBJECTIVES: To help define the relationship between elder abuse rates and counties' demographics, healthcare resources, and social service characteristics. DESIGN: County-level data from Iowa were analyzed to test the association between county characteristics and rates of elder abuse between 1984 and 1993 using univariate correlation analysis and stagewise linear regression. SETTING: Ninety-nine counties in Iowa. PARTICIPANTS: Iowa residents aged 65 years and older. MEASUREMENTS: County-level population-adjusted numbers of abused elderly, abused children, children in poverty, high school dropouts, physicians and other healthcare providers, hospital beds, social workers and caseworkers in the Department of Human Services (DHS). RESULTS: Community characteristics that had a positive association with rates of reported or substantiated elder abuse at the P < .001 level were population density, children in poverty, and reported child abuse. Lower substantiated elder abuse rates were associated at P < .05 with higher community rates of high school dropouts, number of chiropractors, and number of nurse practitioners. After adjusting for number of DHS caseworkers and reported child abuse rates (a surrogate for workload) a district effect persists for substantiated elder abuse cases (P = .002). CONCLUSION: County demographics are risk factors for reported and substantiated elder abuse. The strongest risk factor for reported elder abuse was reported child abuse. The difference in districts may reflect differences in resources and/or differing characteristics of caseworkers who substantiate elder abuse. The risk factors may reflect conditions that influence the amount of elder abuse or the detection of existing elder abuse.

Aged↗
PubMed1999

Pre-transplant identification of risk factors that adversely affect length of stay and charges for renal transplantation.

BACKGROUND: In the current era of renal transplantation, increasing attention is being focused on resource utilization. The purpose of this study was to identify demographic, medical and immunologic risk factors that are associated with changes in length of stay (LOS) and charges for renal transplantation. METHOD: The study was a retrospective analysis of 311 consecutive renal transplants performed at a single institution. Univariate and multivariate analyses were used to examine relationships between risk factors, LOS, charges and post-operative complications. RESULTS: The following pre-transplant variables were found to be independently significant in predicting increased LOS and/or charges: African-American race, obesity for women, chronic obstructive pulmonary disease (COPD), presence of cardiac disease or previous stroke, pre-transplant dialysis time > or = 1 yr, a 10% increase in panel reactive antibody (PRA), cadaver donor and retransplantation. The analyses were performed with and without adjustment for key outcome variables such as delayed graft function (DGF) and use of induction antibody therapy. Increased LOS or charges for specific risk factors could be attributed to increased complication rates, including delayed graft function seen with various co-morbidities, or increased immunologic risk and more frequent use of induction antibody therapy. CONCLUSION: Analysis of linked financial and clinical databases can reveal demographic, medical and immunologic risk factors that correlate with LOS, charges and complications for renal transplantation. Efforts to establish quantitative relationships for various risk factors relative to resource utilization will become important in managed care and/or capitated healthcare delivery systems.

Adult↗
PubMed1999

Prestige of training programs and experience of bypass surgeons as factors in adjusted patient mortality rates.

OBJECTIVES: The relation of physician performance to physician training and experience is not well understood. The aim of this study was to examine whether indicators of physician background and experience were associated with an objective measure of physician performance. METHODS: Physician background information obtained from the Directory of Board-Certified Medical Specialists was linked to physician risk-adjusted mortality rates obtained from three statewide data bases of coronary artery bypass surgeons. Subjects were 275 surgeons who performed CABG surgery on 83,547 patients during the years 1989 to 1992. Surgical performance was measured by the mortality ratio (MR), the ratio of the observed to the predicted patient mortality rate as determined by detailed clinical information. Training institutions and physicians were characterized as prestigious if they were listed as outstanding in published articles. RESULTS: Surgical performance was not associated with graduation from an American medical school; attendance at a prestigious medical school, residency, or fellowship program; or an academic appointment. Mortality ratios decreased with increased volume and increased with years of experience, age, and academic rank. Surgeons were more likely to be considered a "best doctor" if they had more years experience and trained at a prestigious residency or fellowship program. CONCLUSIONS: Training at a prestigious institution was associated with identification as a "best" doctor but not with lower mortality ratios.

Adult↗
PubMed1998

Hospitalization costs associated with homelessness in New York City.

BACKGROUND: Homelessness is believed to be a cause of health problems and high medical costs, but data supporting this association have been difficult to obtain. We compared lengths of stay and reasons for hospital admission among homeless and other low-income persons in New York City to estimate the hospitalization costs associated with homelessness. METHODS: We obtained hospital-discharge data on 18,864 admissions of homeless adults to New York City's public general hospitals (excluding admissions for childbirth) and 383,986 nonmaternity admissions of other low-income adults to all general hospitals in New York City during 1992 and 1993. The differences in length of stay were adjusted for diagnosis-related group, principal diagnosis, selected coexisting illnesses, and demographic characteristics. RESULTS: Of the admissions of homeless people, 51.5 percent were for treatment of substance abuse or mental illness, as compared with 22.8 percent for the other low-income patients, and another 19.7 percent of the admissions of homeless people were for trauma, respiratory disorders, skin disorders, and infectious diseases (excluding the acquired immunodeficiency syndrome [AIDS]), many of which are potentially preventable medical conditions. For the homeless, 80.6 percent of the admissions involved either a principal or a secondary diagnosis of substance abuse or mental illness -- roughly twice the rates for the other patients. The homeless patients stayed 4.1 days, or 36 percent, longer per admission on average than the other patients, even after adjustments were made for differences in the rates of substance abuse and mental illness and other clinical and demographic characteristics. The costs of the additional days per discharge averaged $4,094 for psychiatric patients, $3,370 for patients with AIDS, and $2,414 for all types of patients. CONCLUSIONS: Homelessness is associated with substantial excess costs per hospital stay in New York City. Decisions to fund housing and supportive services for the homeless should take into account the potential of these services to reduce the high costs of hospitalization in this population.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Identification of heavy drinkers using a combination of laboratory tests.

OBJECTIVE: This study derived and evaluated a model that used results of commonly performed laboratory tests to identify men who are heavy drinkers. METHOD: The results of 40 commonly available laboratory tests were obtained on a diverse sample of 426 heavy drinkers and 188 light drinkers. A logistic regression equation for identifying heavy drinkers was derived in a training data set of 411 subjects and tested in a validation data set of 203 subjects. RESULTS: Ten laboratory measurements were included in the final regression equation: chloride, sodium, ratio of direct to total bilirubin level, blood urea nitrogen, high density lipoproteins, monocyte count, phosphorus, platelets, aspartate aminotransferase, and mean corpuscular hemoglobin. In the validation data this model correctly identified 98% of the 161 heavy drinkers and 95% of the 42 light drinkers. Other models reported in previous literature were applied to these subjects and did not perform as well. The model performed better for subjects of lower socioeconomic status. CONCLUSIONS: The laboratory tests in our model may help identify heavy drinkers. The performance of models to identify heavy drinkers depends on the demographic characteristics of the subjects.

Adult↗
PubMed1997

The relationship of the value of outcome comparisons to the number of patients per provider.

PURPOSE: Monte Carlo methods were used to assess how the value of outcome comparisons depends on the number of patients per provider. METHODS: We simulated two patient data sets that have been used for well-known studies of outcome comparisons: mortality rates for coronary artery bypass surgeons from New York and Pennsylvania, and 30-day hospital mortality rates of Medicare patient from a national data set. In the simulated data sets, each surgeon or hospital provider was assigned a true or underlying probability of mortality. RESULTS: For the simulated CABG surgery data set, the underlying probability of mortality explained 30% of the variation in the observed mortality rate when there were 100 patients per physician, and 63% when there were 400 patients. The positive predictive value of using an observed mortality rate in the bottom 10% to identify a surgeon whose underlying probability of mortality was in the bottom 10% was 31% for 100 patients and 59% for 400 patients. The relationship between underlying and observed rates was weaker in the simulated Medicare data set with the same number of patients per provider. For a given data set, the amount of random variation in the observed rates of adverse outcomes among providers can be estimated with a simple equation. CONCLUSION: The results show that the assessment of provider outcomes may be greatly affected by random variation. An indication of the amount of random variation in a given data set can be obtained from the examples in this study and an equation for estimating random variation.

Computer Simulation↗
PubMed1997

Are the best coronary artery bypass surgeons identified by physician surveys?

OBJECTIVES: This study assessed the validity of surveys for identifying the best coronary artery bypass surgeons. METHODS: Data on physicians who performed coronary artery bypass surgery were available from New York, Pennsylvania, and Wisconsin. Data on physicians' reputation were obtained from one national and five city surveys. The measure of surgical performance was the mortality ratio (MR), that is, the ratio of the observed to the predicted patient mortality rate. RESULTS: Mortality ratios were very similar for the 10,722 patients treated by the 31 surgeons defined as "best" doctors in the surveys (MR = 98) and for the 74,854 patients treated by 243 other surgeons who had more than a minimal number of cases (MR = .96). The mortality ratio was 1.34 for the patients treated by surgeons with the lowest volumes and .87 for the surgeons who performed more than 400 coronary artery bypass surgeries in 3 years. CONCLUSIONS: These results suggest that the quality of a coronary artery bypass surgeon may be more closely associated with patient volume than with the surgeon's reputation among peers.

Attitude of Health Personnel↗
PubMed1996

The evaluation of screening methods to identify medically unnecessary hospital stay for patients with pneumonia.

OBJECTIVES: This study compared three methods to screen charts of pneumonia patients for excess days. METHODS: A derivation data set was used to statistically derive a severity measure to predict length of stay for pneumonia patients and to refine a clinical algorithm for identifying excess stay. A validation data set was used to compare three computerized methods to screen for unnecessary hospital days: (1) an observed length of stay greater than a target value; (2) an observed stay greater than predicted for the specific patient; and (3) an algorithm that tested whether there were clinical justifications for the entire hospital stay. RESULTS: The sensitivity and specificity for detecting excess stay for the three methods were (1) 0.48 and 0.85 for the observed stay greater than the target value; (2) 0.56 and 0.73 for observed stay greater than predicted; and (3) 0.83 and 0.85 for the algorithm. CONCLUSIONS: These results suggest that computerized clinical algorithms may provide a useful method to detect unnecessary hospital stay.

Adult↗
PubMed1996

Results of a computerized screening of stroke patients for unjustified hospital stay.

BACKGROUND AND PURPOSE: Effective methods to monitor length of stay can help reduce unnecessary hospital stay without adversely affecting the quality of care. In this study a clinical algorithm for assessing unjustified hospital stay in stroke patients was computerized and tested. METHODS: An algorithm was developed by the authors to estimate the number of medically justified and unjustified hospital days for patients admitted with a primary diagnosis of ischemic stroke. Data for the algorithm were obtained from 177 stroke patients from an acute-care teaching hospital. The performance of the algorithm was evaluated on a subset of 46 patients by comparing the number of medically unjustified hospital days determined by the algorithm with the consensus determination of two neurologists. RESULTS: The algorithm classified 68% of the 177 patients as having some unjustified hospital days and 41% of all hospital days as unjustified. With the neurologists as the gold standard, the sensitivity of the algorithm was .89 and the specificity was .91. The correlation between the number of unjustified days determined by the algorithm and the neurologists was .76. CONCLUSIONS: There is considerable unjustified length of stay for stroke patients. Physicians can develop simple clinical algorithms for detecting unjustified hospital stay in stroke patients that provide a reasonable approximation of complex clinical judgment.

Algorithms↗
PubMed1996

Smoking and idiopathic congestive cardiomyopathy.

Two case control studies were performed to evaluate whether smoking may affect myocardial function. Cardiomyopathy subjects had a greater pack year smoking history than 52 control subjects with no CAD (p < 0.02) and were more likely to have diabetes (p < 0.10), but they did not differ from controls with respect to age, alcohol intake, or the presence of hypertension. The risk of cardiomyopathy doubled with an increase of 39 pack years. Smoking history was not related to ejection for fraction for subjects with severe coronary artery disease. These results suggest that smoking may be an important risk factor for idiopathic congestive cardiomyopathy.

Adult↗
PubMed1995

The elements of statistics for clinical readers.

Statistical courses usually emphasize teaching the mathematical properties of methods to perform statistical significance testing. To interpret clinical studies, however, the reader needs to know only the purpose of the statistical methods, not their mathematical basis. This purpose in most studies is to evaluate the association between a risk factor and an outcome. The evaluation has five components: (1) measure the strength of the association, (2) determine the probability that the observed association did not occur by chance alone, (3) find the range of probable values for the measure of association, (4) reduce the possibility that the association is invalid because of confounding factors, and (5) examine the possibility that the association does not apply equally well to all people because of modulating factors. By focusing on the purposes of the statistical evaluation, the reader will be less distracted by the specific mathematical formulations that provide little additional information to the clinician.

Confidence Intervals↗
PubMed1995

BUN as a risk factor for mortality after coronary artery bypass grafting.

BACKGROUND: Although information on blood urea nitrogen (BUN) is universally available for patients who undergo coronary artery bypass grafting, BUN has not often been considered as a risk factor for mortality. This study assessed BUN as a risk factor for CABG patients. METHODS: Four data sets were evaluated that differed with respect to the types of patients and available patient information. In each of these data sets logistic regression analysis was used to examine the relationship between BUN and mortality after adjusting for other risk factors. RESULTS: Blood urea nitrogen level was strongly associated with mortality in each of the data sets. After adjustment for the available risk factors other than creatinine level, patients with BUN levels greater than 30 mg/dL had a relative odds of mortality ranging between 1.86 and 2.49 (p < 0.0001 in three of the data sets). Even after adjustment for creatinine level as well as the other variables, BUN was statistically significant at the p less than 0.01 level for three of the data sets. CONCLUSIONS: The results suggest that BUN provides additional information on cardiac function that supplements the information provided by other risk factors.

Aged↗