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Biomedical subjects

M D Silverstein

Publications and source records attributed to M D Silverstein.

At least 55 records · Page 3Linked to original sources
PubMed1997

The Mayo Ventilator-Dependent Rehabilitation Unit: a 5-year experience.

OBJECTIVE: To describe the outcomes of 206 patients admitted to the Mayo Ventilator-Dependent Rehabilitation Unit (VDRU) during a 5-year study period. DESIGN: We analyze the patient data for 1990 through 1994, which had been prospectively entered into a computer database for a cohort of 206 patients who had become ventilator dependent during their current hospitalization. MATERIAL AND METHODS: Patients in the VDRU were classified into one of six categories that reflected the reasons for ventilator dependence. Ability to be weaned from mechanical ventilation, duration of hospital stay and ventilator dependence, outcome, disposition, demographics, and long-term survival were analyzed. The VDRU patient group was compared for hospital and follow-up outcomes with a group of historical control patients previously described by us. RESULTS: The Mayo VDRU was established in January 1990. During the first 5 years of its operation, 206 newly ventilator-dependent patients were admitted to the VDRU, 190 (92%) of whom survived to be dismissed; 16 patients (8%) died in the hospital. Of the 190 patients dismissed, 77% were able to return to their homes. Overall, 153 patients were liberated from mechanical ventilation, whereas 37 remained either completely or partially ventilator dependent. Of these 37 patients, 27 (73%) were receiving nocturnal mechanical ventilation only. The 4-year survival was 53%. CONCLUSION: The Mayo VDRU has been highly successful in liberating newly ventilator-dependent patients from mechanical ventilation. The long-term survival after management in the VDRU has been excellent. In addition, the medical charges for care in the VDRU are less than intensive-care unit charges.

Adolescent↗
PubMed1996

Skeletal, cardiac, and smooth muscle failure in Duchenne muscular dystrophy.

The goals of this study were to describe the clinical course of skeletal, cardiac, and gastrointestinal muscle manifestations and trends in age at diagnosis and survival of Duchenne muscular dystrophy (DMD) patients. A retrospective cohort of 33 male patients with DMD, born between 1953 and 1983 and followed at the Mayo Clinic during their second decade of life, was studied. The mean age at DMD diagnosis was 4.6 years. Skeletal muscle weakness present in all patients at diagnosis progressed to wheelchair dependency in 32 patients (97%) by the age of 13 years (median age 10 years). Cardiac muscle failure developed in 5 patients (15%) (median age 21.5 years). Smooth muscle manifestations related to the digestive and urinary tracts occurred in 7 (21%) and 2 (6%) patients (median age 15 years), respectively. The gastrointestinal dilatations were primary in 2 patients or secondary to surgery or acute respiratory illness in 5 patients. By the end of the study period, 17 deaths had occurred (median age 17 years). Over time, there was a decrease in the time to DMD diagnosis (P = .05) but no significant change in survival (P = .44). Cardiac and smooth muscle manifestations occur late in the course of DMD. Clinical gastrointestinal symptoms related to smooth muscle function most often were secondary to surgery or a respiratory illness. In recent years, the diagnosis of DMD has been made at a younger age, but survival has not changed.

Adolescent↗
PubMed1996

Yield of laboratory tests for case-finding in the ambulatory general medical examination.

PURPOSE: To examine the diagnostic and therapeutic yield of frequently obtained laboratory tests for case-finding in the comprehensive ambulatory medical examination. PATIENTS AND METHODS: A prospective cohort study was conducted in four Mayo Clinic general internal medicine divisions that provide care to community, regional, and geographically distant patients. The main outcome measurements were the diagnostic yield and therapeutic yield of the complete blood count, chemistry panel, lipid profile, thyroid tests, and urinalysis ordered for case-finding. RESULTS: Overall, 1,508 laboratory tests consisting of 7,008 individual components were obtained for case-finding in the 531 patients (mean age 63 +/- 14 years; 57% female). Thirty-six percent (544 of 1508) of the tests were abnormal, of which 6% (33 of 544) were repeated and 9% (47 of 544) led to further investigations. The 1,508 case-finding tests had a diagnostic yield of 4.8% (73 new diagnoses) and a therapeutic yield of 4.0% (60 new therapies). The therapeutic yield of each test ordered for case-finding was as follows: lipid profile (16.5%), chemistry panel (2.8%), complete blood count (0.9%), urinalysis (0.8%), and thyroid tests (0.7%). Therapeutic yield was not associated with patient's age, gender, or referral distance but was approximately twice as high in new patients compared with established patients. CONCLUSIONS: The majority of treatments for conditions identified by case-finding laboratory tests resulted from the lipid profile. The therapeutic yield of the chemistry panel was low, and the therapeutic yield of the complete blood count, thyroid tests, and urinalysis were all less than 1%. The low therapeutic yield of many routine laboratory tests ordered for case-finding should be provided to patients, physicians, and managed care organizations to set priorities for case-finding and screening.

Aged↗
PubMed1996

High-grade astrocytomas: resource use, clinical outcomes, and cost of care.

OBJECTIVE: To describe the clinical course, survival, resource use, and direct medical costs of care for patients with high-grade astrocytomas. MATERIAL AND METHODS: All patients with grade 3 or 4 astrocytoma who resided in Olmsted County, Minnesota, or one of the six adjacent counties and had a tissue diagnosis first made between 1987 and 1992 were studied. Clinical characteristics, initial management, use of resources, clinical course, survival, and medical charges were analyzed. RESULTS: Sixty-four patients, with a mean age of 62 years, were identified; 81% had glioblastoma multiforme. Approximately 60% underwent surgical resection, 80% had radiotherapy, and 50% had chemotherapy for initial management. After initial treatment (median duration, 116 days), approximately 75% of patients had a course with stable disease (median duration, 198 days). The overall median duration of survival was 323 days; lower grade and younger age were significantly associated with longer median survival-for example, 1,493 days for patients younger than 65 years with grade 3 astrocytomas and 205 days for patients 65 years old or older with grade 4 astrocytomas. The mean total direct medical charges were $67,887. CONCLUSION: In most patients with high-grade astrocytomas, a substantial period elapsed before disease progressed. Although the overall median duration of survival was less than 1 year, younger patients, especially those with grade 3 astrocytomas, had a longer survival. The management of patients with high-grade astrocytomas uses substantial health-care resources.

Adult↗
PubMed1996

Outcome after Colles fracture: the relative responsiveness of three questionnaires and physical examination measures.

Clinical evaluation of outcome after Colles fracture has not been standardized. To assess the relative responsiveness of various clinical and questionnaire measures for the assessment of outcome after Colles fracture, 21 patients were surveyed on the day fracture immobilization was discontinued and again 3 months after that date with the following measures: a short form general health survey (SF-36), the Arthritis Impact Measurement Scale (AIMS2), the Brigham and Women's Hospital carpal tunnel questionnaire; pinch strength, grip strength, pressure sensibility, range of motion, and dexterity. Significant changes, all in the direction of improved health status, occurred in the following scales or measures: AIMS2 mobility, hand and finger function, arm function, household tasks, "arthritis" (fracture) pain, self-care, satisfaction, physical health, affect, and tension; Brigham function; SF-36 physical role and mental health; and grip, pinch, dexterity, and range of motion. The impairments that occur after Colles fracture are multidimensional and are only partially captured by traditional physical measures. Questionnaires such as the SF-36, AIMS2, and Brigham and Women's instruments provide a mechanism to capture the function and symptom dimensions objectively.

Colles' Fracture↗
PubMed1996

Outcome assessment for carpal tunnel surgery: the relative responsiveness of generic, arthritis-specific, disease-specific, and physical examination measures.

Clinical evaluation of outcome after treatment of carpal tunnel syndrome has not been standardized. To assess the value of various clinical and questionnaire measures for the assessment of outcome after carpal tunnel surgery, we surveyed 22 patients 1 day before and 3 months after carpal tunnel release with the following measures: the Medical Outcomes Study 36-item short form health survey, the Arthritis Impact Measurement Scale, the Brigham and Women's Hospital carpal tunnel questionnaire, wrist range of motion, power pinch grip strength, pressure sensibility, and dexterity. Significant changes, all in the direction of improved health status postoperatively, were noted in the following scales or measures: the Arthritis Impact Measurement Scale pain, satisfaction, health perception, arthritis impact, and symptom scales; the Brigham and Women's Hospital symptom and function scales; the short form health survey's physical role, emotional role, and bodily pain scales; and the measurement of dexterity. In this study, standardized questionnaires were more sensitive to the clinical change produced by carpal tunnel surgery than many commonly performed physical measures of outcome. The condition-specific questionnaire was more sensitive to change than were more generic questionnaires.

Activities of Daily Living↗
PubMed1996

Initial endoscopy or empirical therapy with or without testing for Helicobacter pylori for dyspepsia: a decision analysis.

BACKGROUND & AIMS: Empirical therapy has been proposed for initial management of dyspepsia. The aim of this study was to evaluate initial endoscopy, empirical therapy, and testing for Helicobacter pylori in the management of patients with a new onset of dyspepsia. METHODS: Decision analysis was used to compare the direct medical charges in the first year after the onset of dyspepsia for patients managed by initial endoscopy or empirical therapy, with or without initial testing for H. pylori. RESULTS: Medical care charges were $2162.50 for initial endoscopy and $2122.60 for empirical therapy, a difference of 1.8%. For a 55-year-old adult, life expectancy was 23.49 years for initial endoscopy compared with 23.48 years for empirical therapy. Empirical therapy has lower charges than initial endoscopy when H2-receptor antagonists are used to prevent recurrence of dyspepsia. Initial noninvasive testing for H. pylori has lower charges than initial endoscopy if patients with dyspepsia with H. pylori receive antimicrobial therapy without endoscopy but would have higher charges if patients with H. pylori routinely have endoscopy. CONCLUSIONS: Surprisingly, the choice of optimal management strategy was a "toss-up." Only modest savings may result from practice guidelines that recommend empirical therapy in the management of patients with dyspepsia.

Adult↗
PubMed1996

Patient-physician agreement about medical diagnoses and cardiovascular risk factors in the ambulatory general medical examination.

OBJECTIVE: To describe the spectrum of medical diagnoses and cardiovascular risk factors identified by physicians during the comprehensive medical examination in ambulatory patients, to assess how accurately patients report the health problems identified by their physicians, and to determine the characteristics associated with patient and physician agreement. MATERIAL AND METHODS: We conducted a prospective study of ambulatory patients at Mayo Clinic Rochester. All 64 internists in the general internal medicine divisions who perform comprehensive medical examinations were invited to enroll 10 adult patients each; 57 physicians and 566 eligible patients participated. Complete physician and patient information on diagnosed health problems was available for 458 patient visits (81%). Diagnosed health problems were collected from both the patients and the physicians by questionnaire after the examination and classified into medical diagnoses and cardiovascular risk factors. RESULTS: Of the diagnosed health problems, 63% involved four organ system categories: (1) nutritional, endocrine, or metabolic (20%); (2) cardiovascular (18%); (3) musculoskeletal (13%); and (4) digestive (12%). Patients failed to report 68% of all health problems and 54% of the most important health problems diagnosed by the physician. Major health problems, new diagnoses, and distant residence were associated with the highest level of patient-physician agreement for diagnosed health problems. CONCLUSION: Because patients failed to report more than half of their most important health problems identified by their physicians, practitioners might consider giving problem lists or summary letters to patients to improve and reinforce communication and management of health problems.

Ambulatory Care↗
PubMed1996

Epiglottitis in adults and children in Olmsted County, Minnesota, 1976 through 1990.

OBJECTIVE: To compare the initial clinical manifestations and sequelae of epiglottitis among children and adult residents of Olmsted County, Minnesota. MATERIAL AND METHODS: We conducted a population-based retrospective cohort study of all Olmsted County residents with the diagnosis of epiglottitis during the 15-year period from Jan. 1, 1976, through Dec. 31, 1990. RESULTS: From 1976 through 1990, 41 residents (20 children and 21 adults) of Olmsted County were diagnosed with epiglottitis. (One case in an adult was first diagnosed at autopsy and was included only in the incidence rates and analysis of seasonal and secular trends.) Children had a mean annual incidence rate of 4.25 per 100,000, whereas the rate in adults was 2.18 per 100,000. The age- and sex-adjusted incidence of epiglottitis decreased during the study period from 4.94 per 100,000 during 1976 through 1980 to 2.08 per 100,000 during 1986 through 1990. No seasonal effect was detected in adults or children. At initial assessment, adults tended to have pharyngeal symptoms (sore throat and odynophagia), cervical adenopathy, and ear pain, whereas children most often had respiratory (stridor, dyspnea, and retractions) and laryngeal symptoms. Proportionately, more children than adults received artificial airway support and had associated pneumonia. One death occurred in an adult, in whom the diagnosis was made at autopsy. CONCLUSION: The incidence of epiglottitis has decreased significantly in recent years. Children and adults have considerably different initial manifestations of epiglottitis.

Adolescent↗
PubMed1995

Review of systems, physical examination, and routine tests for case-finding in ambulatory patients.

The screening value of the comprehensive review of systems and the complete physical examination in detecting unsuspected diseases for which therapeutic interventions are initiated has not been formally studied in ambulatory patients. The medical records of 100 randomly selected adult patients who had an ambulatory general medical evaluation at the Mayo Clinic in 1990-1991 were surveyed to compare review of systems and physical examination with routine laboratory tests, chest radiography, and electrocardiography as case-finding maneuvers. The main outcome measure was the therapeutic yield of each case-finding maneuver, defined as the proportion of maneuvers leading to a new therapy for a new clinically important diagnosis. The utilization rate of routine tests in the 100 patients (mean age: 59 +/- 16 years; 58% women) was high, ranging from 77 to 98%. Overall, the case-finding maneuvers led to 36 unsuspected clinically important diagnoses and resulted in 25 new therapeutic interventions. Higher therapeutic yield was observed for review of systems (7%), physical examination (5%), and lipid screening (9.2%) than for chemistry group (2.2%), complete blood count (1.8%), thyroid tests (1.5%), urinalysis (1.1%), electrocardiography (0%), or chest radiography (0%). The number of therapeutic interventions was not associated with patient's age (P = 0.55), sex (P = 0.88), comorbidity (P = 0.30) or with the time interval since the last general medical evaluation (P = 0.12). Based on therapeutic yield, these data suggest that review of systems and physical examination are valuable case-finding maneuvers in the periodic medical evaluation of ambulatory patients.

Adult↗
PubMed1995

Outcome of patients cared for in a ventilator-dependent unit in a general hospital.

We describe our initial experience with the admission of 129 patients for 132 episodes of ventilator-dependence to a self-contained ventilator-dependent unit (VDU) in a general hospital and present a survival comparison between VDU patients and a historic control population from the same institution. Forty-three patients were screened and denied admission to the VDU because long-term ventilator dependence was not felt to be a probable outcome (56%); they were medically unstable, often requiring electrocardiographic monitoring (19%), they had poor rehabilitation potential because of markedly depressed mental status (13%), or they preferred to be treated closer to their homes (12%). Thirteen (9.8%) of the VDU patients died in the hospital compared to 44 (42%) in the historic control group. After exclusion of patients with multiorgan failure (who made up 26% of the control group) and using a proportional hazard model to adjust for group differences in age and disease class, the difference in hospital mortality remained highly significant (p < or = 0.01). Ninety-one of the 119 VDU patients (77%) were ultimately able to return home; 16 (13%) continued to use a ventilator intermittently at night; 26 patients (22%) were permanently placed in nursing homes, all off of the ventilator. Overall, 88% of the 119 patients discharged had been liberated from mechanical ventilation. Ninety-seven (82%) and 86 (72%) remain alive 1 and 2 years after discharge, respectively. Some of the survival benefits may be directly attributed to the VDU. Others reflect a change in treatment philosophy, which was nevertheless reinforced by our VDU experience.

Adult↗
PubMed1995

Bleeding and thromboembolism during anticoagulant therapy: a population-based study in Rochester, Minnesota.

OBJECTIVE: To estimate the incidence of and identify risk factors for hemorrhage and thromboembolism during long-term anticoagulant therapy. DESIGN: We conducted a population-based retrospective cohort study of all residents of Rochester, Minnesota, in whom a course of warfarin therapy intended to last for more than 4 weeks was initiated between Sept. 1, 1987, and Dec. 31, 1989. METHODS: Medical records were reviewed, and pertinent data were compiled. All bleeding complications were classified as minor or major on the basis of the bleeding severity index, and thromboembolic events were classified as major if they were fatal or life-threatening. Cumulative incidences of adverse events were analyzed statistically. RESULTS: During the study period, 261 patients had incident courses of anticoagulation (52% were male, 61% were 65 years of age or older, and 31% were 75 years of age or older), with 221 patient-years of warfarin exposure. The primary indications for anticoagulation were venous thromboembolism (39%); stroke or transient ischemic attack (21%); atrial fibrillation (11%); and coronary artery disease, procedures for coronary artery disease, or cardiomyopathy (7%). The cumulative incidence of major hemorrhage at 1, 3, 12, and 24 months was 1.6%, 3.3%, 5.3%, and 10.6%, respectively, and of major or minor thromboembolic events was 2.3%, 5.0%, 7.4%, and 13.1%, respectively. In multivariate analysis, (1) a malignant condition was significantly associated with major hemorrhage; (2) malignant disease and history of peptic ulcer were significantly associated with the combined outcome of major or minor hemorrhage; and (3) malignant disease was significantly associated with any thromboembolism. Age, sex, atrial fibrillation, history of gastrointestinal hemorrhage, history of peptic ulcer, alcohol abuse, hypertension, stroke, and the Charlson comorbidity index were not significantly associated with major hemorrhage. CONCLUSION: In this population-based study, including a high proportion of elderly patients, malignant disease at initiation of warfarin anticoagulation was significantly associated with both major hemorrhage and any thromboembolism. Advanced age is not a contraindication to anticoagulant therapy.

Age Factors↗
PubMed1995

Utilization and outcomes of surgical gastrostomies and jejunostomies in an era of percutaneous endoscopic gastrostomy: a population-based study.

OBJECTIVE: To determine the indications for use of surgical gastrostomy (SG) and surgical jejunostomy (SJ) as feeding tubes, the complications, and the trends in the use of SG and SJ after the introduction of percutaneous endoscopic gastrostomy (PEG) at our institution in 1981. DESIGN: We conducted a retrospective, population-based cohort study of residents of Olmsted County, Minnesota, who received surgically placed feeding tubes between 1976 and 1989. MATERIAL AND METHODS: The medical records of all Olmsted County residents with surgical placement of a feeding tube during the designated study period were reviewed, and underlying conditions, complications, and survival were analyzed. RESULTS: Of 77 adult patients (mean age, 66 years; 48% women), 54 underwent SG and 23 had SJ. General anesthesia was used in 42 patients (55%). The indications for SG or SJ were stroke in 23 patients, cancer in 19, other central nervous system-related conditions in 16, and other conditions in 19. Among the numerous comorbid conditions, pulmonary disease (N = 44) and cardiac disease (N = 32) were most frequent. The median duration of follow-up was 181 days. Complications occurred in 31 of 54 patients (57%) with SG and in 13 of 23 (57%) with SJ. Of the 117 complications, 15% were considered major. Twenty patients (26%) resumed eating. Survival at 1, 6, and 12 months was 79%, 49% and 36%, respectively. Most deaths were due to the disease for which the feeding tube had been placed. In a Cox proportional hazards regression analysis, only age and hypoxemia were found to be significantly associated with survival. Hypoxemia, type of tube, central nervous system disease as indication for procedure, and previous aspiration were associated with failure to resume eating (P < 0.05). Survival was similar to that for our patients with PEG during the same period. The overall incidence of feeding tube placement increased throughout the study period. CONCLUSION: Patients who require enteral feeding tubes have multiple comorbid conditions that have a major influence on the outcome. The overall incidence of feeding tube placement increased after the introduction of PEG. In patients who require long-term enteral nutrition and are unable to have a feeding tube placed percutaneously, surgically placed feeding tubes have outcomes similar to those reported for patients with PEG.

Aged↗
PubMed1994

Long-term survival of a cohort of community residents with asthma.

BACKGROUND: Reports of an increase in asthma-related mortality have been based on studies of death certificates from the general U.S. population on which asthma was listed as an underlying cause of death. We addressed the issue in a different way by analyzing long-term survival in a defined, population-based cohort of patients with asthma. METHODS: We identified all residents of Rochester, Minnesota, in whom asthma was diagnosed from January 1, 1964, through December 31, 1983, by reviewing the medical records of all patients with asthma and associated diagnoses, using explicit predefined criteria. The patients' vital status at last follow-up was ascertained. Medical records, death certificates, and autopsy reports were reviewed to classify deaths as due either to asthma or to other conditions. RESULTS: We identified 2499 patients with definite or probable asthma. The mean duration of follow-up was 14 years (range, 0 to 29). There were 140 deaths during 32,605 person-years of follow-up. Overall survival was not significantly different from the survival that was expected for residents of Rochester. Survival was less than expected in patients who were 35 years of age or older when their asthma was diagnosed and who also had another lung disease (predominantly chronic obstructive pulmonary disease). Four percent of all deaths in the study cohort were due to asthma, and all were among adults. Survival was not related to the year of onset of asthma. CONCLUSIONS: Survival among patients with asthma but no other lung disease was not significantly different from expected survival. However, patients 35 or older who had asthma associated with chronic obstructive pulmonary disease did have worse than expected survival. Asthma was classified as the cause of death in only 4 percent of the patients, and there was no evidence of an increased risk of death among patients with a more recent diagnosis of asthma. These results provide assurance that community-based patients with asthma usually have a good prognosis.

Adolescent↗
PubMed1994

Cigarette smoking and ulcerative colitis: a case-control study.

OBJECTIVE: To determine whether the previously reported decreased risk of ulcerative colitis in current smokers and increased risk in former smokers are explained by age, sex, race, ethnicity, or socioeconomic status. DESIGN: We conducted a case-control study at a university hospital gastroenterology clinic. MATERIAL AND METHODS: One hundred patients with ulcerative colitis and 100 age- and sex-matched community control subjects were randomly selected for a telephone interview to collect information on smoking habits, race, religion, income, education, and occupation. Smoking habits at the onset of symptoms were analyzed with use of conditional logistic regression for matched data to obtain adjusted odds ratios and 95% confidence intervals for current or former smokers. RESULTS: In comparison with those who had never smoked, current smokers were less likely to have ulcerative colitis: odds ratio = 0.13; 95% confidence interval = 0.05 to 0.38. Former smokers had no increased risk for ulcerative colitis: odds ratio = 1.24; 95% confidence interval = 0.52 to 2.95. No dose-response effect was noted on the basis of pack-years of cigarette smoking, and among former smokers, the interval since quitting smoking was not significantly associated with the relative risk of ulcerative colitis. No confounding effect was detected from race, religion, income, education, or occupation. CONCLUSION: An association seems to exist between ulcerative colitis and nonsmoking; perhaps patients with ulcerative colitis who smoke are less likely to experience symptoms than are nonsmokers because of the effects of nicotine.

Adult↗
PubMed1994

Conceptual framework for evaluating laboratory tests: case-finding in ambulatory patients.

In response to concerns about inappropriate testing and healthcare costs, clinicians and laboratorians should work together to evaluate laboratory tests. Studies of routine laboratory tests ordered for screening and case-finding in the preoperative setting, at hospital admission, and in the ambulatory setting have not provided sufficient evidence of the benefits of case-finding when evaluated against commonly used criteria for screening procedures. We adapt a conceptual framework developed from radiology for evaluating imaging technologies to evaluate laboratory tests. The framework addresses diagnostic efficacy (whether the test correctly identifies abnormalities), diagnostic effectiveness (whether the test changes the physician's diagnoses), therapeutic efficacy (whether the test changes patient management), and therapeutic effectiveness (whether the test changes patients' outcomes). We propose that clinicians and laboratorians use this framework to evaluate the diagnostic efficacy, diagnostic effectiveness, therapeutic efficacy, and therapeutic effectiveness of laboratory tests in the ambulatory setting and in other settings.

Clinical Laboratory Techniques↗
PubMed1993

Prophylactic agents for venous thrombosis in elective hip surgery. Meta-analysis of studies using venographic assessment.

BACKGROUND: We determined the relative efficacy of various agents or combinations of agents in the prophylaxis of deep venous thrombosis after elective hip arthroplasty. METHODS: Peer-reviewed, English-language, human studies articles from 1975 through 1991 were obtained through a MEDLINE database search. Additional references were obtained from bibliographies. Articles that compared the effect of two or more prophylactic agents or placebo in preventing deep venous thrombosis as assessed by venography were selected for further review. Only studies of elective hip surgery in which all patients had venographic screening for thrombosis were included. Twenty-three of 101 studies met these criteria. Data were abstracted by one of us. Methodologic criteria and outcome data from each study were recorded and analyzed. RESULTS: There was significant heterogeneity in the deep venous thrombosis rate among studies. Although the rates were lowest for low-molecular-weight heparin with or without the use of stockings, adjusted-dose heparin, and warfarin, many agents had similar low rates. There was less heterogeneity when the relative risk was used as a summary statistic for studies in which two agents were compared. With pairwise comparisons, low-molecular-weight heparin performed better than every agent with which it was compared. Other agents performed well but were not consistently better. CONCLUSIONS: Multiple agents or combinations are effective prophylaxis for deep venous thrombosis, but none decreases the rate to zero. There was overlap in the 95% confidence intervals for the probability of deep venous thrombosis for various agents and especially for the probabilities for proximal thrombi. Many agents have not been compared directly with each other, but low-molecular-weight heparin consistently performed well.

Anticoagulants↗