Biomedical subjects

E R DeLong

Publications and source records attributed to E R DeLong.

At least 37 records · Page 2Linked to original sources

PubMed1997

Geographic variation in resource use for coronary artery bypass surgery. IHD Port Investigators.

OBJECTIVES: The purpose of this study was to examine the national variability in patient-level cost and length of stay for coronary artery bypass grafting (CABG) in Medicare patients. METHODS: Retrospective multivariate regression analysis was done using Medicare administrative files and American Hospital Association files. Patients in the study had an International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) procedure code for CABG, with accompanying 1990 procedure data, in the Medicare Provider Analysis and Review File (n = 92,449). RESULTS: Outcome measures used were inpatient cost (exclusive of professional fees) and inpatient length of stay associated with bypass admission. The national average cost of bypass surgery was $22,847 (median $18,783), with an accompanying average length of stay of 16 days (median 13 days). Multivariate regression analysis revealed that patient-level cost and length of stay were related to clinical, demographic, hospital, and regional characteristics (R2 = 25% and 16%, respectively). After accounting for these characteristics at the patient level, considerable variation among states persisted in both cost and length of stay. In addition, states with similar adjusted lengths of stay varied widely with respect to adjusted cost. No relation was found at the state level between level of resource use and either procedural mortality or 60-day mortality/readmission rates. CONCLUSIONS: Considerable variability exists among states in patient-level cost and length of stay for CABG surgery, after adjusting to the extent possible for clinical, demographic, hospital, and regional characteristics. The lack of association at the state level between resource use and rates of mortality and hospital readmission suggests that costs could be reduced in many areas of the United States without compromising quality of care.

Aged↗

PubMed1996

Outcome of acute myocardial infarction according to the specialty of the admitting physician.

BACKGROUND: In order to limit costs, health care organizations in the United States are shifting medical care from specialists to primary care physicians. Although primary care physicians provide less resource-intensive care, there is little information concerning the effects of this strategy on outcomes. METHODS: We examined mortality according to the specialty of the admitting physician among 8241 Medicare patients who were hospitalized for acute myocardial infarction in four states during a seven-month period in 1992. Proportional-hazards regression models were used to examine survival up to one year after the myocardial infarction. To determine the generalizability of our findings, we also examined insurance claims and survival data for all 220,535 patients for whom there were Medicare claims for hospital care for acute myocardial infarction in 1992. RESULTS: After adjustment for characteristics of the patients and hospitals, patients who were admitted to the hospital by a cardiologist were 12 percent less likely to die within one year than those admitted by a primary care physician (P<0.001). Cardiologists also had the highest rate of use of cardiac procedures and medications, including medications (such as thrombolytic agents and beta-blockers) that are associated with improved survival. CONCLUSIONS: Health care strategies that shift the care of elderly patients with myocardial infarction from cardiologists to primary care physicians lower rates of use of resources (and potentially lower costs), but they may also cause decreased survival. Additional information is needed to elucidate how primary care physicians and specialists should interact in the care of severely ill patients.

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PubMed1996

Impact of an interactive video on decision making of patients with ischemic heart disease.

An experimental pilot study using repeated measures to examine the impact of an interactive video program on the decision making of patients with ischemic heart disease was carried on at a tertiary care center and a Veterans Affairs hospital. The patients (n = 80, mean age 61.1 years, 77% male, 75% white, 26.7% with acute myocardial infarction), who had undergone diagnostic cardiac catheterization and were found to have significant coronary artery disease (> or = 75% stenosis in at least one vessel), watched the Shared Decision-Making Program (SDP) for Ischemic Heart Disease (IHD), a novel interactive video system designed to provide information necessary for patients to participate actively in decision making. This program compares medical therapy, angioplasty, and bypass surgery through a physician narrator, patient testimonials, and empirically-based, patient-specific outcome estimates of short-time complications and long-term survival. Before and after viewing the SDP, patients completed surveys containing multiple choice questions and Likert scales. They rated the program as more helpful than all other decision aids except the physician, and after viewing the SDP they expressed increased confidence in their treatment choice and decreased confidence in alternative options (p = .0001). The greatest effects appeared to be concentrated in those patients with less education (p = .04), and the program appeared to increase anxiety in nonwhite patients compared with white patients (p = 0.07).

Decision Making↗

PubMed1996

Predicting the presence of choledocholithiasis in patients with symptomatic cholelithiasis.

OBJECTIVES: Accurate preoperative prediction of choledocholithiasis is essential in order to minimize patient risk and curtail health care expenditures. This study was designed to identify independent risk factors for choledocholithiasis in patients who had undergone cholecystectomy for symptomatic cholelithiasis and to develop a predictive model based on those factors. METHODS: The charts of 1264 consecutive patients who had undergone cholecystectomy at one of three North Carolina hospitals between January 1, 1989 and December 31, 1991 were reviewed; 465 of these patients had confirmed presence or absence of choledocholithiasis by cholangiography and/or common bile duct exploration and were eligible for analysis. Candidate predictor variables included age and maximum preoperative values for each of the following: temperature, alkaline phosphatase, bilirubin, AST, amylase, white blood cell count, and common bile duct diameter. Model development and validation were conducted using standard data-splitting (60% "training," 40% "test") and logistic regression techniques. RESULTS: Choledocholithiasis was confirmed in 115 (25%) of the 465 eligible patients. Univariate analysis identified bilirubin, common bile duct diameter, AST, temperature, alkaline phosphatase, and age as predictors. Multivariable analysis subsequently identified bilirubin, common bile duct diameter, AST, alkaline phosphatase, and age as independent predictors of choledocholithiasis. A final model containing these variables (except age, whose contribution to the model was small) accurately predicted choledocholithiasis (c-index = 0.76). CONCLUSIONS: Accurate estimates of choledocholithiasis risk can be made using maximum preoperative bilirubin, common bile duct diameter, AST, and alkaline phosphatase values. Use of the model may help physicians select those patients with symptomatic cholelithiasis who would most likely benefit from further investigation to exclude choledocholithiasis.

Case-Control Studies↗

PubMed1995

Outcomes of coronary artery bypass graft surgery in 24,461 patients aged 80 years or older.

BACKGROUND: Coronary artery bypass graft surgery is increasingly common in patients of age > or = 80 years. Single-institution reviews have cited a wide range of mortality results after bypass surgery in this age group, in part because of limited sample sizes. Using claims data, we examined recent national trends in the use and outcomes of bypass surgery in the very elderly. METHODS AND RESULTS: From an examination of Medicare data from 1987 through 1990, we identified 24,461 patients of age > or = 80 years who underwent bypass surgery. We compared surgical outcomes in these patients with those in Medicare patients of age 65 to 70 years. We found that the national use of bypass surgery in patients of age > or = 80 years increased 67% between 1987 and 1990. Compared with patients of age 65 to 70 years, the very elderly had significantly longer postoperative hospital stays (mean, 14.3 versus 10.4 days), higher charges (mean, $48,200 versus $38,000), and greater costs (mean, $27,200 versus $21,700). In-hospital (11.5% versus 4.4%), 1-year (19.3% versus 7.9%), and 3-year mortality rates (28.8% versus 13.1%) after bypass surgery were also significantly higher in patients of age > or = 80 years compared with younger patients. Although their initial surgical risk was high, octogenarians who underwent bypass surgery had a long-term survival rate similar to that of the general US octogenarian population. CONCLUSIONS: The use of bypass surgery in patients of age > or = 80 years in increasing. These very elderly patients face high surgical risks and accumulate significant hospital expenses. Further research is indicated to determine whether the long-term benefits from bypass surgery in the very elderly outweigh the increased procedural risks.

Age Factors↗

PubMed1995

Measuring hospital mortality rates: are 30-day data enough? Ischemic Heart Disease Patient Outcomes Research Team.

OBJECTIVE: We compare 30-day and 180-day postadmission hospital mortality rates for all Medicare patients and those in three categories of cardiac care: coronary artery bypass graft surgery, acute myocardial infarction, and congestive heart failure. DATA SOURCES/COLLECTION: Health Care Financing Administration (HCFA) hospital mortality data for FY 1989. STUDY DESIGN: Using hospital level public use files of actual and predicted mortality at 30 and 180 days, we constructed residual mortality measures for each hospital. We ranked hospitals and used receiver operating characteristic (ROC) curves to compare 0-30, 31-180, and 0-180-day postadmission mortality. PRINCIPAL FINDINGS: For the admissions we studied, we found a broad range of hospital performance when we ranked hospitals using the 30-day data; some hospitals had much lower than predicted 30-day mortality rates, while others had much higher than predicted mortality rates. Data from the time period 31-180 days postadmission yield results that corroborate the 0-30 day postadmission data. Moreover, we found evidence that hospital performance on one condition is related to performance on the other conditions, but that the correlation is much weaker in the 31-180-day interval than in the 0-30-day period. Using ROC curves, we found that the 30-day data discriminated the top and bottom fifths of the 180-day data extremely well, especially for AMI outcomes. CONCLUSIONS: Using data on cumulative hospital mortality from 180 days postadmission does not yield a different perspective from using data from 30 days postadmission for the conditions we studied.

Cardiology Service, Hospital↗

PubMed1994

The relation between the volume of coronary angioplasty procedures at hospitals treating Medicare beneficiaries and short-term mortality.

BACKGROUND: Previous studies have found that hospitals at which more procedures, such as coronary-artery bypass grafting (CABG) and other vascular surgery, are performed have lower rates of mortality related to these procedures than hospitals where fewer such procedures are performed. METHODS: We examined the relation between the number of percutaneous transluminal coronary angioplasty (PTCA) procedures performed at hospitals (volume) and short-term mortality in a population of 217,836 Medicare beneficiaries 65 years of age or older who underwent angioplasty in the United States from 1987 through 1990. RESULTS: The unadjusted in-hospital mortality among patients who underwent PTCA increased from 2.5 percent among the 10 percent of patients treated in hospitals with the highest volume of such procedures to 3.9 percent among the 10 percent of patients treated in hospitals with the lowest volume. The rate of bypass surgery after PTCA also increased, from 2.8 percent among patients in the highest-volume hospitals to 5.3 percent among those in the lowest-volume hospitals. Higher rates of mortality and CABG persisted in all the groups of patients treated in hospitals that performed fewer than 100 angioplasty procedures per year in Medicare beneficiaries; this volume in Medicare beneficiaries can be extrapolated to an overall annual volume of 200 to 400 angioplasty procedures. In a logistic-regression model, the volume of PTCA procedures at a hospital was found to be a highly significant predictor of in-hospital mortality (P < 0.001). These results suggest that if the hospitals with the lowest volume had achieved the experience and technical results of the highest-volume hospitals, 381 fewer patients would have undergone CABG and there would have been 300 fewer in-hospital deaths in the population we studied. CONCLUSIONS: Hospitals that perform more PTCA procedures have lower short-term mortality rates after the procedure. These data provide evidence in support of the regionalization of angioplasty services.

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PubMed1994

Changes in mortality after myocardial revascularization in the elderly. The national Medicare experience.

OBJECTIVE: To examine secular changes in the use and outcome of percutaneous transluminal coronary angioplasty and cardiac bypass graft surgery in the elderly. DESIGN: A retrospective cohort study based on a longitudinal database created from the administrative files of Medicare. SETTING: U.S. hospitals that perform myocardial revascularization procedures covered by Medicare. PATIENTS: 225,915 consecutive patients who had angioplasty and 357,885 consecutive patients who had bypass surgery from 1987 to 1990. MEASUREMENTS: The rates of angioplasty and bypass surgery use; unadjusted 30-day and 1-year mortality rates after revascularization; and adjusted odds ratios for mortality by year of procedure for 1987 to 1990. RESULTS: From 1987 to 1990, the rates of angioplasty and bypass surgery done in the elderly increased by 55% and 18%, respectively. During this period, 30-day unadjusted mortality rates after angioplasty and bypass surgery decreased by 25% (95% CI, 22% to 28%) and 12% (CI, 10% to 14%), and 1-year mortality rates decreased by 10% (CI, 8% to 11%) and 8% (CI, 7% to 10%), respectively. After adjustment for changes in patient characteristics, 30-day mortality rates after these procedures decreased by 37% (CI, 32% to 41%) and 18% (CI, 14% to 21%), and 1-year mortality rates decreased by 22% (CI, 18% to 25%) and 19% (CI, 16% to 21%), respectively. CONCLUSIONS: The use of cardiac revascularization procedures in the elderly has steadily increased. Patients who had revascularization are progressively older, have more coded comorbid conditions, and present with more acute diseases. Although elderly patients have apparently higher risk profiles, mortality rates after angioplasty and bypass surgery in the elderly have decreased, suggesting a national improvement in the outcomes of these interventions. Health policy decisions concerning revascularization procedures in the elderly must consider these trends in improved outcome.

Age Factors↗

PubMed1994

Absence of sex bias in the referral of patients for cardiac catheterization.

BACKGROUND: It has been suggested that women with clinical evidence of coronary artery disease are less often referred for cardiac catheterization than are men. To determine whether there is sex-related bias in referral for cardiac catheterization, we prospectively studied a cohort of 410 symptomatic outpatients (280 men and 130 women) who were being evaluated with exercise testing for possible-coronary artery disease. METHODS: Before the patients underwent exercise testing, 15 cardiologists from an academic medical center were asked to predict the probability that the patients they saw in the cardiology clinic would have angiographic evidence of any obstructive coronary disease (stenosis of 75 percent or more); the probability of severe coronary disease (three-vessel or left main coronary artery disease); the probability of left main coronary artery disease; and the probability of survival one, three, and five years after the evaluation. Similar predictions were generated by previously validated statistical models with use of data collected before exercise testing from the history, physical examination, and 12-lead electrocardiography with the patient at rest. RESULTS: Overall, women were referred for cardiac catheterization significantly less often than men (18 percent vs. 27 percent, P = 0.03). As compared with men, women had a significantly lower pretest probability of coronary disease (as estimated by their physicians) and a lower rate of positive exercise-test results. After accounting for differences in these two factors, sex was not an independent predictor of referral for catheterization. Comparing physicians' estimates of outcome with those generated by the statistical models revealed no evidence that the physicians were underestimating the risk of coronary disease in women. Furthermore, physicians' predictions did not underestimate the probability of any obstructive coronary disease in men and women who subsequently underwent catheterization. CONCLUSIONS: Academic cardiologists made appropriately lower pretest predictions of categories of disease in women with possible coronary artery disease than in men, and these assessments, along with women's lower rate of positive exercise tests, rather than bias based on sex, accounted for the lower rate of catheterization among women.

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PubMed1994

Programmed Outcome Research Teams (PORTs) and implications for clinical practice.

The spiraling cost of health care has created a health care crisis. Concerns about the appropriate use of expensive medical technologies have been heightened by health services research studies that demonstrate widespread and dramatic geographic variability in the use of tests and procedures. The Agency for Health Care Policy and Research has funded 14 Programmed Outcome Research Teams (PORTs) targeted at specific disease entities. The PORT in ischemic heart disease is examining 2 principal decisions--which patients should undergo cardiac catheterization and, following catheterization, how patients should be treated. The PORT in ischemic heart disease combines information from the literature, 18 databases, and patient preference studies in models examining these 2 decisions. The databases have also been used to develop statistical models that estimate outcomes with different therapies. The benefit of a therapy in a population can be illustrated using an empirically derived, marginal value curve that describes the expected improvement in outcome (e.g., survival) that accrues with additional procedures performed in patients who are most likely to benefit.

Cardiac Catheterization↗

PubMed1993

Discordance of databases designed for claims payment versus clinical information systems. Implications for outcomes research.

OBJECTIVE: To determine the suitability of insurance claims information for use in clinical outcomes research in ischemic heart disease. DESIGN: Concordance study of two databases. SETTING: Tertiary care referral center. PATIENTS: A total of 12,937 consecutive patients hospitalized for cardiac catheterization for suspected ischemic heart disease between July 1985 and May 1990. INTERVENTIONS: Two-by-two tables were used to compute overall and kappa measures of agreement comparing clinical versus claims data for 12 important predictors of prognosis in patients with ischemic heart disease. MEASUREMENTS: Kappa statistics (agreement adjusted for chance agreement) were used to quantify agreement rates. RESULTS: Agreement rates between the clinical and claims databases ranged from 0.83 for the diagnosis of diabetes to 0.09 for the diagnosis of unstable angina (kappa values). Claims data failed to identify more than one half of the patients with prognostically important conditions, including mitral insufficiency, congestive heart failure, peripheral vascular disease, old myocardial infarction, hyperlipidemia, cerebrovascular disease, tobacco use, angina, and unstable angina, when compared with the clinical information system. CONCLUSIONS: Our results suggest that insurance claims data lack important diagnostic and prognostic information when compared with concurrently collected clinical data in the study of ischemic heart disease. Thus, insurance claims data are not as useful as clinical data for identifying clinically relevant patient groups and for adjusting for risk in outcome studies, such as analyses of hospital mortality.

Cardiac Catheterization↗

PubMed1990

Five-year follow-up of men with androgenetic alopecia treated with topical minoxidil.

Thirty-one men with androgenetic alopecia completed 4 1/2 to 5 years of therapy with 2% and 3% topical minoxidil. Hair regrowth with topical minoxidil tended to peak at 1 year with a slow decline in regrowth over subsequent years. However, at 4 1/2 to 5 years, maintenance of nonvellus hairs beyond that seen at baseline was still evident. Topical minoxidil appears to be effective in helping to maintain nonvellus hair growth in men with androgenetic alopecia.

Administration, Cutaneous↗

PubMed1990

Randomized, double-blind, placebo-controlled, patient-initiated study of topical high- and low-dose interferon-alpha with nonoxynol-9 in the treatment of recurrent genital herpes.

To explore further topical antiviral therapy for recurrent genital herpes, 188 culture-proven patients were randomized to receive treatment with topical interferon-alpha in high-dose (10(6) IU/g with 1% nonoxynol-9 in 3.5% methylcellulose) or low-dose (10(3) IU/g with 0.1% nonoxynol-9 in 3.5% methylcellulose) treatments or placebo (3.5% methylcellulose, alone), applied three times daily for 5 days. Of these, 105 experienced prodromal symptoms within the study period and applied the medication, of whom 99 could be evaluated for efficacy. Patients were followed with daily clinical assessments and cultures until reepithelialization. The median time to negative virus culture in high-dose recipients was 2.5 days compared with 3.9 days for placebo recipients (P = .023), and a significant dose response was observed (P = .016). Antiviral effects were more prominent in men than women. High-dose recipients also had reduced median duration of symptoms to 2.7 days from 3.7 days for placebo recipients (P = .03), with a significant dose-response relationship (P = .047). Effects on duration of symptoms were more prominent in women. Times to complete reepithelialization in those who applied the drug during the prodromal phase were 5.8 days for high-dose recipients compared with 6.5 days for placebo recipients (P = .053). A multivariate ranked linear model analysis of four efficacy variables (crusting, healing, virus shedding, symptom duration) also favored the high-dose gel (P = .015). High-dose topical interferon-alpha preparation is effective for patients with recurrent genital herpes. Applied early in the course of a recurrent episode, this treatment is safe and may provide a topical alternative to other types of therapy in the future.

Administration, Topical↗

PubMed1990

Impact of glucose self-monitoring on non-insulin-treated patients with type II diabetes mellitus. Randomized controlled trial comparing blood and urine testing.

The goal of this study was to compare the relative efficacy and cost of self-monitoring of blood glucose (SMBG) with routine urine testing in the management of patients with type II (non-insulin-dependent) diabetes mellitus not treated with insulin. Fifty-four patients with type II diabetes mellitus, not treated with insulin, who had inadequate glucose control on diet alone or diet and oral hypoglycemic agents were studied. Patients performed SMBG or urine glucose testing as part of a standardized treatment program that also included diet and exercise counseling. During the 6-mo study, both the urine-testing and SMBG groups showed similar improvement in glycemic control; within each group, there were significant improvements in fasting plasma glucose (reduction of 1.4 +/- 3.2 mM, P less than 0.03) and glycosylated hemoglobin (reduction of 2.0 +/- 3.4%, P less than 0.01) levels. Seventeen (31%) of 54 patients actually normalized their glycosylated hemoglobin values, 9 in the urine-testing group and 8 in the SMBG group. Comparisons between the urine-testing and SMBG groups showed no significant differences in mean fasting plasma glucose (P greater than 0.86), glycosylated hemoglobin (P greater than 0.95), or weight (P greater than 0.19). In patients with type II diabetes mellitus not treated with insulin, SMBG is no more effective, but is 8-12 times more expensive, than urine testing in facilitating improved glycemic control. Our results do not support widespread use of SMBG in diabetic patients not treated with insulin.

Aged↗

PubMed1988

Impact of a medical journal club on house-staff reading habits, knowledge, and critical appraisal skills. A randomized control trial.

The journal club is an established teaching modality in many house-staff training programs. To determine if a journal club improves house-staff reading habits, knowledge of epidemiology and biostatistics, and critical appraisal skills, we randomized 44 medical interns to receive either a journal club or a control seminar series. A test instrument developed by the Delphi method was administered before and after the interventions (mean, five journal club sessions). By self-report, 86% of the house staff in the journal club group improved their reading habits vs 0% in the control group. Knowledge scores increased more in the journal club group than in the control group, and a trend was found toward more knowledge gained as more sessions were attended. Ability to appraise critically a test article increased slightly in each group, but there was no significant difference between the groups. We conclude that a journal club is a powerful motivator of critical house-staff reading behavior and can help teach epidemiology and biostatistics to physicians-in-training.

Biometry↗

PubMed1988

Erythrocyte anisocytosis. Visual inspection of blood films vs automated analysis of red blood cell distribution width.

An improved anemia classification may be available by combining measures of red blood cell size variability with mean corpuscular volume. Visual inspection of the peripheral blood film allows semiquantitative description of anisocytosis while quantitative measures are determined from electronic cell counter analyzers' red blood cell distribution width. We evaluated correlations between semiquantitative and quantitative measures of anisocytosis for different groups of observers. Hematologists', medical students', and medical residents' semiquantitative assessment of anisocytosis correlated with the quantitative red blood cell distribution width. The interobserver variability demonstrated that all observers correlated with each other, while the intraobserver variability of semiquantitative anisocytosis demonstrated that observers were more precise than could be predicted by chance. However, the extreme precision of the red blood cell distribution width strongly suggests that it should be the "gold standard" for measuring red blood cell size variability.

Anemia↗

PubMed1988

Intestinal obstruction in patients with ovarian cancer. Variables associated with surgical complications and survival.

Intestinal obstruction is frequently encountered in patients with ovarian cancer. Surgical correction of intestinal obstruction may allow the prolonged survival of some patients. We identified prognostic factors associated with operative complications and postoperative survival. Multiple preoperative, intraoperative, and postoperative variables were considered. In addition, a previously published prognostic index was evaluated. Statistical assessment developed a model that demonstrated that the clinical assessment of tumor status, the serum albumin level, and the nutrition score were variables significantly associated with postoperative survival. The amount of residual ovarian cancer at the completion of bowel obstruction surgery was also significantly associated with postoperative survival. This information may aid in the preoperative selection of patients who might benefit from surgical correction of intestinal obstruction.

Aged↗

PubMed1988

Comparing the areas under two or more correlated receiver operating characteristic curves: a nonparametric approach.

Methods of evaluating and comparing the performance of diagnostic tests are of increasing importance as new tests are developed and marketed. When a test is based on an observed variable that lies on a continuous or graded scale, an assessment of the overall value of the test can be made through the use of a receiver operating characteristic (ROC) curve. The curve is constructed by varying the cutpoint used to determine which values of the observed variable will be considered abnormal and then plotting the resulting sensitivities against the corresponding false positive rates. When two or more empirical curves are constructed based on tests performed on the same individuals, statistical analysis on differences between curves must take into account the correlated nature of the data. This paper presents a nonparametric approach to the analysis of areas under correlated ROC curves, by using the theory on generalized U-statistics to generate an estimated covariance matrix.

Algorithms↗