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Biomedical subjects

B Littenberg

Publications and source records attributed to B Littenberg.

At least 19 recordsLinked to original sources

The development and validation of an instrument to assess acute sinus disease in children.

Our goal was to produce a reliable, responsive instrument to quantify disease burden in children with acute sinusitis for use in clinical trials. In a cross sectional survey of 1611 community pediatric patients, parents rated the burden attributable to 13 sinus symptoms. Using logistic regression, we identified five symptoms that predicted the clinical diagnosis of sinusitis. The S5 is the average symptom score for nasal obstruction, daytime and nighttime coughing, headache and colored nasal discharge (range 0-3). The S5 was high in children with acute sinusitis (mean = 1.54, SD = 0.77, N = 93), and low in well children (mean = 0.42, SD = 0.56, N = 1019). We assessed reliability and responsiveness of S5 in a prospective cohort study of 41 children with sinusitis. Parents completed a questionnaire at the office visit, at 12 h and 3, 7, 10 and 14 days. Intra-subject reliability at 12 h was excellent (ICC = 0.94). The S5 score was responsive in 24 patients followed for 14 days who improved (mean change = 1.52, SD = 0.12, p = 0.0062). The S5 score is standardized, reliable, responsive, easily obtained, and can be used to determine study eligibility and assess treatment effects without a physician's evaluation.

Acute Disease

Enteric carriage of vancomycin-resistant Enterococcus faecium in patients tested for Clostridium difficile.

OBJECTIVE: To identify independent risk factors for enteric carriage of vancomycin-resistant Enterococcus faecium (VREF) in hospitalized patients tested for Clostridium difficile toxin. DESIGN: Retrospective case-cohort study. SETTING: Tertiary-care teaching hospital. PATIENTS: Convenience sample of 215 adult inpatients who had stool tested for C difficile between January 29 and February 25, 1996. RESULTS: 41 (19%) of 215 patients had enteric carriage of VREE Five independent risk factors for enteric VREF were identified: history of prior C difficile (odds ratio [OR], 15.21; 95% confidence interval [CI95], 3.30-70.10; P < .001), parenteral treatment with vancomycin for > or = 5 days (OR, 4.06; CI95, 1.54-10.73; P = .005), treatment with antimicrobials effective against gram-negative organisms (OR, 3.44; CI95, 1.20-9.87; P = .021), admission from another institution (OR, 2.95; CI95, 1.21-7.18; P =.017), and age > 60 years (OR 2.57; CI95, 1.13-5.82; P = .024). These risk factors for enteric VREF were independent of the patient's current C difficile status. CONCLUSIONS: Antimicrobial exposures are the most important modifiable independent risk factors for enteric carriage of VREF in hospitalized patients tested for C difficile.

Adult

Meta-analysis of randomized controlled trials comparing laparoscopic and open appendectomy.

We performed a meta-analysis to determine whether laparoscopic or open appendectomy gives better outcomes for patients with suspected acute appendicitis. Studies were selected from the MEDLINE database, personal files, and meeting abstracts. Eleven of 21 randomized controlled trials were included in the meta-analysis. Pooled effect size estimates were calculated using a random effects model. Laparoscopic appendectomy reduced time to full functioning by 5.48 days (95% confidence interval [CI] 3.70 to 7.26; p < 0.001), improved postoperative pain at 24 hours measured by a visual analog scale from 0 to 10 by 1.19 points (95% CI -2.14 to -0.24 points; p=0.014), and decreased the absolute risk for wound infection by 3.2% (95% CI -5.6% to -0. 8%; p=0.009). Operating time was increased by 17.12 min (95% CI 14.19 to 20.03; p < 0.0001). There was no difference between the two surgeries for length of hospital stay, readmission rate, and intra-abdominal abscess formation. Laparoscopic appendectomy improves patient outcomes.

Appendectomy

Effectiveness of helicopter versus ground ambulance services for interfacility transport.

BACKGROUND: Helicopters provide rapid interfacility transport, but the effect on patients is largely unknown. METHODS: Patients requested to be transported between facilities by helicopter were followed prospectively to determine survival, disability, health status, and health care utilization. A total of 1,234 patients were transported by the primary aeromedical company; 153 patients were transported by ground and 25 patients were transported by other aeromedical services because of weather or unavailability of aircraft. RESULTS: There were no differences at 30 days for survivors in disability, health status, or health care utilization. Nineteen percent of helicopter-transported patients died compared with 15% of those transported by ground (p=0.21). CONCLUSION: The patients transported by helicopter did not have improved outcomes compared with patients transported by ground. These data argue against a large advantage of helicopters for interfacility transport. A randomized trial is needed to address these issues conclusively.

Adult

Closed fractures of the tibial shaft. A meta-analysis of three methods of treatment.

We reviewed the literature to determine the clinical outcomes of the treatment of closed fractures of the tibial shaft with immobilization in a cast, open reduction with internal fixation, or fixation with an intramedullary rod. We reviewed 2372 reports of comparative trials and uncontrolled studies of series of patients published between 1966 and 1993. Nineteen reports, involving six controlled trials and twenty-seven groups of patients, met our inclusion criteria. A structured questionnaire was used to assess the quality of the literature in terms of the experimental design and the method of assessment of outcome. Outcomes from controlled trials were summarized with odds ratios and risk differences, and outcomes from case series were summarized by the medians of the reported results. The studies that were reviewed generally had few subjects and were poorly designed. The comparative trials showed treatment with a cast to be associated with a lower rate of superficial infection than open reduction and internal fixation (mean difference, -5.81 per cent; p = 0.02) and open reduction and internal fixation to be associated with a higher rate of union by twenty weeks than treatment with a cast (mean difference, -18.07 per cent; p = 0.008). There were no other significant associations. There were insufficient data for us to evaluate any aspect of functional status, level of pain, or other patient-reported outcomes of any of the methods of treatment. The results of the present review suggest that the data from the published literature are inadequate for decision-making with regard to the treatment of closed fractures of the tibia.

Casts, Surgical

A meta-analysis of extended-interval dosing versus multiple daily dosing of aminoglycosides.

We conducted a meta-analysis of 22 randomized, controlled trials in which extended-interval dosing of aminoglycosides was compared with multiple daily dosing. When we classified intermediate outcomes as successes, we found that patients receiving extended-interval dosing were at significantly reduced risk of clinical treatment failure (risk difference, -3.4%; 95% confidence interval [CI], -6.7% to -0.2%; P = .039) and that there was a trend toward reduced risk of bacteriologic failure (risk difference, -1.7%; 95% CI, -5.4% to +2.1%; P = .38). Reclassification of intermediate outcomes as failures yielded similar results. There was significant heterogeneity among the trials, necessitating cautious interpretation of these outcomes. There were negligible differences in the risk of nephrotoxicity (risk difference, -0.6%; 95% CI, -2.4% to +1.1%; P = .46) and ototoxicity (risk difference, +0.3%; 95% CI, -1.2% to +1.8%; P = .71). We conclude that for many indications, extended-interval dosing of aminoglycosides appears to be as effective as conventional dosing, with similar rates of toxicity. The added convenience of extended-interval dosing makes it an attractive alternative to conventional dosing.

Aminoglycosides

Theophylline in acute childhood asthma: a meta-analysis of its efficacy.

Although theophylline is a widely used drug for the treatment of acute childhood asthma, its efficacy has not been clearly established. This study constitutes a meta-analysis of published randomized clinical trials of theophylline in children hospitalized with acute asthma. We conducted a search of English language MEDLINE citations from 1966 to 1995 and analyzed the methods of each report meeting study criteria. We pooled similar clinical measures across studies if a test for homogeneity of effect size was non-significant. The six methodologically acceptable randomized clinical trials included a total of 164 children less than 18 years of age. Incomplete reporting of measures and variances was common. No study included children in intensive care settings. Using pooled results, pulmonary function parameters [forced expired volume in 1 second (FEV1), forced expired flow (FEF)] appeared better at 24 hours in the theophylline group, but the results did not reach statistical significance (mean effect difference, + 3.9% predicted values; pooled effect size, + 1.6 SDS; P = 0.25). A mean of 2.1 more albuterol treatments were administered in the theophylline group (pooled effect size, - 0.18 SDS; P = 0.02), and the mean hospital stay was slightly longer (mean effect difference, - 0.31 days; pooled effect size, - 0.18 SDS; P = 0.03). We conclude that currently available data do not indicate a significant beneficial effect of theophylline in children hospitalized with acute asthma. There is evidence for weak detrimental effects. Theophylline efficacy in intensive care unit settings remains unstudied.

Acute Disease

Automated utility assessment of global health.

The objective of this study was to characterize the performance of an automated utility assessment instrument for measuring preferences for overall health. The study population consisted of 83 subjects recruited from the cafeteria of a large tertiary care hospital. We assessed utilities for current health relative to perfect health and death using the rating scale, time tradeoff and standard gamble metrics. To validate the instrument, we compared utilities with the General Health subscale of the SF-36 Health Survey instrument, satisfaction with current health, and degree of bother due to current health. We evaluated interview failure rate based on irrational orderings of two practice assessments (monocular and binocular blindness) or inability to complete the interview. As expected, utility for overall health was statistically significantly associated with the General Health subscale score and measures of satisfaction with current health and degree of bother. There is substantial variation in utilities among patients with similarly severe overall health, and substantial overlap in utilities among subjects with different levels of overall health. The failure rate in the study was acceptable (9.6%). Automated assessment of utility for overall health provides a feasible means for estimating individual preferences.

Adult

The effect of an educational intervention on the perceived risk of breast cancer.

OBJECTIVE: To appraise women's perceived risk of developing breast cancer and the effects of a physician's educational intervention on this perception. DESIGN: Longitudinal before-and-after study involving four measures of participants risk of developing breast cancer. Eligible women provided the data needed to calculate an objective estimate of their individual risk of developing breast cancer before age 80 using the Gail formula. They also provided a subjective estimate of their individual perceived risk. Then, each participant met with a general internal medicine physician who provided personalized information and education. Immediately after education, and again several months later, we reassessed each woman's perceived risk. SETTING: Physicians office. PARTICIPANTS: A convenience sample of 59 women participating in the Tamoxifen Breast Cancer Prevention Trial. Twenty-nine women returned for the follow-up risk assessment. MEASUREMENTS AND MAIN RESULTS: The median calculated risk of breast cancer before age 80 (by the Gail formula) was 15%, but the median perceived risk before educational intervention was 50%. The perceived risk after educational intervention fell to 25%. At late follow-up, the median perceived risk remained at 25%. The difference between the preeducational perceptions and the calculated estimates was significant (1) < .0001). After educational intervention, perceived risk measures shifted closer to the calculated value, but still remained significantly higher (p <.0001). CONCLUSIONS: Women often substantially overestimate their chances of getting breast cancer. Educational intervention by a physician, including explanation of an individual's calculated risk, can reduce this error. The effect of education appears to persist at least for several months.

Adult

Clinical prediction rules to optimize cytotoxin testing for Clostridium difficile in hospitalized patients with diarrhea.

BACKGROUND: Although routine testing of hospitalized patients with diarrhea for Clostridium difficile cytotoxin has been advocated as a high-yield procedure, the rationale for this practice has been questioned. To target a low-yield subgroup for whom routine testing could be deferred, we derived a clinical decision rule for predicting results of the C difficile cytotoxin assay in hospitalized adults with diarrhea. METHODS: We hypothesized a priori that two variables, antibiotic use (within 30 days prior to testing) and history of significant diarrhea (new onset of > 3 partially formed or watery stools per 24 hour period), would be highly predictive of cytotoxin results, and obtained these data on 480 consecutive patients who underwent diagnostic testing for C difficile at a university hospital and affiliated Veterans Affairs medical center. For more detailed modelling, we recorded symptoms, signs, comorbidity, and other potential causes of diarrhea for 68 test positive patients (cases) and 265 randomly selected test negative patients (controls) within the study cohort. RESULTS: The overall prevalence of positive cytotoxin assays was 14%. Prior antibiotic therapy (OR = 9.0, 95% CI 2.1-38.4), significant diarrhea (OR = 2.2, 95% CI 1.1-4.7), and abdominal pain (OR = 1.9, 95% CI 0.96-3.7) were independent predictors of cytotoxin assay results. The model discriminated patients with positive and negative assays with a receiver operating characteristic (ROC) area of 0.68; observed and predicted probabilities of a positive cytotoxin assay were well correlated over the entire range of observed probabilities (r2 = 0.86). A decision rule (defined as positive if prior antibiotic use and either significant diarrhea or abdominal pain are present) demonstrated sensitivity and specificity of 86 and 45%. When applied to the entire dataset (N = 480), a simplified a priori rule, defined as positive if both prior antibiotic use and history of significant diarrhea are present, demonstrated sensitivity, specificity, positive and negative predictive value of 80, 45, 18 and 94%, respectively (6% of those predicted to be cytotoxin-negative actually tested positive). Use of this rule would have averted 39% of cytotoxin assays in our study population. CONCLUSIONS: Patients without prior antibiotic use and either significant diarrhea or abdominal pain are unlikely to have positive C difficile cytotoxin assay results, and may not routinely require cytotoxin testing.

Abdominal Pain

A cost-effectiveness analysis of the use of a mechanical barrier system to reduce the risk of mistransfusion.

BACKGROUND: A blood component is transfused to a patient other than the intended recipient because of patient and sample identification problems once in about every 24,000 transfusions. An investigation was performed of the cost-effectiveness of a barrier system to prevent mistransfusion of a unit of red cells through this kind of error. STUDY DESIGN AND METHODS: A decision analysis model was constructed that took into account nonfatal and fatal events, costs of patient care, and legal costs. The model was used to determine the cost-effectiveness of the barrier system in terms of cost per year of life saved and lives saved per million transfusions. RESULTS: The barrier system is predicted to save 1.5 lives per million transfusions when used as intended. If the cost-effectiveness calculations are based on an average damage award for a fatality of more than $725,000 and a chance of mistransfusion exceeding 1 in 16,700, use of the system results in reduced healthcare expenditures. If no legal costs are included in the cost-effectiveness calculations, use of the system costs $197,000 per year of life saved. Routine use of the system extends patient life by 1 year per 60,000 units transfused. CONCLUSION: The application of a barrier system to prevent mistransfusion and related morbidity and mortality can be cost-effective. If legal costs are included in the calculations, the use of a barrier system reduces total costs.

Blood Group Incompatibility

Surgeons' decision making in patients with chronic wrist pain: role of bilateral three-compartment wrist arthrography--prospective study.

PURPOSE: To determine if wrist arthrography changes surgeons' diagnoses and treatment plans for patients with chronic wrist pain. MATERIALS AND METHODS: Bilateral, three-compartment wrist arthrography was performed in 64 patients. Prospective questionnaires evaluated surgeons' diagnoses and management plans at three stages: before arthrography, after arthrography of the symptomatic wrist, and after arthrography of the asymptomatic wrist. RESULTS: Surgeons tended to plan more conservative management after receiving the results of arthrography. The number of patients for whom the reported treatment plan included surgery dropped from 28 of 64 patients (44%) to 19 of 64 patients (30%) after review of the arthrography results (P = .05). The number of patients for whom the treatment plan included treatment of any kind dropped from 55 of 64 patients (86%) to 49 of 64 patients (77%) after review of the arthrography results (P = .09). An overall change in treatment plan occurred in 29 of 64 patients (45%). CONCLUSION: Wrist arthrography influences surgeons' decision making. After reviewing the results of arthrography, surgeons tended to change treatment plans toward more conservative, less invasive treatment.

Adult

Dyspnea ratings for prescribing exercise intensity in patients with COPD.

STUDY OBJECTIVE: We tested the hypothesis that patients with COPD can use dyspnea ratings obtained from a prior graded exercise test as a target to reliably produce specific exercise intensities. DESIGN: Four visits over a 7-week period. SETTING: Pulmonary function and cardiorespiratory exercise laboratory at a university hospital. PATIENTS: Fifteen symptomatic patients with stable COPD. Age was 68 +/- 7 (mean +/- SD) years. FEV1 was 1.12 +/- 0.22 L (45 +/- 8% predicted). INTERVENTIONS: At each visit, patients estimated the heaviness of weights to evaluate their magnitude estimation of a nonrespiratory task; after pulmonary function testing was completed, patients were tested on the cycle ergometer. At estimation trial 1 (day 0), patients estimated the intensity of dyspnea using the 0 to 10 category-ratio scale during an incremental exercise test. Estimation trial 2 (day 5 to 7) was the same as the previous trial. At production trials 1 (day 10 to 14) and 2 (day 40 to 44), patients were instructed to produce specific intensities of dyspnea (ie, dyspnea targets) at 50% and at anaerobic threshold (AT) or 80% of peak oxygen consumption (Vo2) as calculated from results at estimation trial 2. MEASUREMENTS AND RESULTS: Lung function was stable at all visits. Dyspnea ratings were 1.8 +/- 0.9 (range, 1 to 3) at 50% of peak Vo2 and 5.5 +/- 1.5 (range, 4 to 8) at AT/80% of peak Vo2 (17.0 +/- 3.4 mL/kg/min) at estimation trial 2. The individual percent changes in Vo2 at the lower dyspnea target were 12 +/- 19% and 11 +/- 19% for production trials 1 and 2, respectively, compared with estimation trial 2. At the higher dyspnea target, the corresponding individual percent changes in Vo2 were -4 +/- 9% and -7 +/- 11%, respectively. For all 15 patients, there were borderline statistical differences for the Vo2 values at the lower (p = 0.04 and p = 0.07) and at the higher (p = 0.04 for each production trial) dyspnea targets for production trials 1 and 2 compared with estimation trial 2. Two patients showed 50% or greater variability in the calculated exponent for magnitude estimation of weights. In a subgroup analysis of the 13 patients with reproducible magnitude estimation of the heaviness of weights, there were no significant differences in Vo2 for the two production trials compared with estimation trial 2 at both exercise intensities. CONCLUSIONS: Dyspnea ratings obtained from an incremental exercise test can be used as a target for patients with COPD to regulate/monitor the intensity of exercise training. The ability of patients with COPD to achieve a desired Vo2 based on an individual dyspnea target was generally more accurate at the higher exercise level (AT/80% of peak Vo2) compared with the lower intensity (50% of peak Vo2). Acceptable accuracy was maintained over a 5-week time period.

Aged

The New Hampshire Mammography Network: the development and design of a population-based registry.

OBJECTIVE: Some authors have proposed a national mammography registry to improve and monitor breast diagnostic practices. However, issues such as confidentiality, accuracy, and direct and indirect costs are practical barriers to implementing such a registry. This paper describes the development and design of a population-based mammography registry in New Hampshire. The project's objectives are to assess the accuracy of mammography by comparing interpretive results with pathology and tumor-registry reports and to improve mammographic performance by reporting findings to facilities, radiologists, and pathologists statewide. MATERIALS AND METHODS: We recruited radiologists and pathologists through professional associations and facilities through site visits. Data used to develop and design the registry were collected during site visits, using structured face-to-face interview methods. Only one site refused to provide site-specific information. RESULTS: Facilities in New Hampshire estimated the annual mammographic volume to be approximately 148,000. We have noted a great deal of variability in mammography practices. Their principal methods for determining screening versus diagnostic mammograms were by patient self-reports (44% of practices), referring physicians' reports (38%), and radiologists' reports (18%). Although 71% of practices have computers, only 16% have radiology information systems or hospital information systems that offer computerized patient-tracking capabilities. More than 90% of New Hampshire radiologists exclusively use freehand dictation for reporting, and although almost 50% codify reports, only 11% use the American College of Radiology lexicon. These data and concerns expressed by radiologists, pathologists, technologists, and administrators helped shape the New Hampshire registry. CONCLUSION: Heterogeneity of radiologic practices poses major challenges for implementing a population-based mammography registry. Issues such as confidentiality, the difficulty of assessing diagnostic acumen, and the time involved in providing data to a registry must be adequately addressed. For the registry to succeed in such diverse settings, researchers, radiologists, pathologists, technologists, and administrative staff must collaborate and cooperate.

Adult

A randomized controlled trial of oral albuterol in acute cough.

BACKGROUND: Beta-agonist agents have been used for bronchospasm and cough in a variety of settings. We sought to evaluate the efficacy of oral albuterol for acute cough in ambulatory adults. METHODS: We performed a prospective, randomized, controlled, double-blind clinical trial comparing albuterol 4 mg by mouth three times daily for 7 days with placebo in 104 adults. Subjects had cough of less than 4 weeks' duration and no evidence of pneumonia, asthma, or chronic obstructive pulmonary disease. All subjects were enrolled at the walk-in clinic of a rural academic medical center. RESULTS: There was no significant difference between treated and control subjects in any measure of efficacy including cough severity score, reduction in sleepless nights, utilization of health care, or return to full activity. There were significantly more reports of "shakiness" and "nervousness" among albuterol-treated subjects than among controls. CONCLUSIONS: Oral albuterol should not be used in unselected patients with acute, nonspecific cough.

Acute Disease

A practice guideline revisited: screening for hypertension.

In 1993, the Clinical Efficacy Assessment Subcommittee began evaluation of new topics and reevaluation of previous guidelines on common screening tests, which were published in Annals of Internal Medicine between 1988 and 1990 and republished as a collection in 1991 (Eddy DM, ed. Common Screening Tests. Philadelphia: American College of Physicians; 1991). Of the 11 guidelines contained in Common Screening Tests, only 3 (for breast, colon, and cholesterol screening) will be published with new data supporting new recommendations. Dr. Littenberg's analysis of the evidence that has appeared since the publication of the original paper on screening for hypertension (Littenberg B, Garber AM, Sox HC. Screening for Hypertension. Ann Intern Med. 1990;112:192-202) presents a new format for updating Clinical Efficacy Assessment Project (CEAP) guidelines that have not been altered by new evidence. This "updated guideline" reports on new published studies and its analysis affirms the approved American College of Physicians recommendations of 1990. The Clinical Efficacy Assessment Subcommittee carried out the Internal and external review procedures that are used for all CEAP guidelines. The plan is to keep all American College of Physicians guidelines updated in this way on a regular basis. Direct any comments or suggestions to Director, Scientific Policy, American College of Physicians, 6th Street at Race, Philadelphia, PA 19106.

Cost-Benefit Analysis