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H S Sacks

Publications and source records attributed to H S Sacks.

At least 55 records · Page 3Linked to original sources
PubMed1990

Endoscopic hemostasis. An effective therapy for bleeding peptic ulcers.

We performed a meta-analysis of 25 randomized control trials that compared endoscopic hemostasis with standard therapy for bleeding peptic ulcer. For recurrent or continued bleeding, the mean rate in control patients was 0.39, and the pooled rate difference, or reduction due to therapy, was 0.27 +/- 0.15 (95% confidence interval) (69% relative reduction). For emergency surgery, the mean rate in control patients was 0.26, and the pooled rate difference was 0.16 +/- 0.05 (62% relative reduction). Most important, for overall mortality, the mean rate in control patients was 0.10, and the pooled rate difference was 0.03 +/- 0.02 (30% relative reduction). The effects were greatest in patients with spurting or visible blood vessels and equivocal when the ulcer showed only signs of recent bleeding. We conclude that endoscopic hemostasis is clearly effective but that data were insufficient for direct comparisons between modalities. Randomized control trials to compare the different modes of endoscopic therapy should continue.

Adult↗
PubMed1990

Dipyridamole in the treatment of angina pectoris: a meta-analysis.

A meta-analysis of 11 randomized trials published between 1960 and 1970 was performed to re-evaluate data on the efficacy of dipyridamole in the prevention and treatment of chronic angina pectoris. Three trials significantly favored drug vs placebo, four showed a trend towards drug vs placebo, two showed no difference and two showed a trend towards placebo vs drug. The combined results of these 11 trials showed a statistically significant improvement with dipyridamole. Although this result should be viewed with caution because of methodologic variations in the studies, the available evidence appears to suggest that dipyridamole may have a beneficial effect, and that it may have been prematurely discarded in the treatment of angina pectoris.

Angina Pectoris↗
PubMed1989

A comparison of statistical methods for combining event rates from clinical trials.

We compare two statistical methods for combining event rates from several studies. Both methods treat each study as a separate stratum. The Peto-modified Mantel-Haenszel (Peto) method estimates a combined odds ratio assuming homogeneity across strata and provides a test for heterogeneity. The DerSimonian and Laird modified Cochran method (D&L) produces a weighted average of rate differences, where the weights allow for among-study variability. We analyse 22 meta-analyses from ten reports by both methods. The pooled estimates are divided by their standard errors to produce a Z-statistic. A t-test comparing Z-statistics from all 22 studies suggests that the D&L method tends to be more conservative [d(Peto - D&L) = 0.29, t = 2.53, p = 0.02]. For a subset of 14 non-heterogeneous studies, the difference is smaller and non-significant (d = 0.09, t = 0.72, p = 0.49). The results from the methods correlate well (r = 0.66 for all 22 studies, r = 0.95 for 14 non-heterogeneous studies). Thus, the presence of heterogeneity influences our conclusion. We discuss the statistical and scientific implications of these findings.

Clinical Trials as Topic↗
PubMed1989

Selection and evaluation of empirical research in technology assessment.

Technology assessment involves application of the scientific method to the practice of medicine. Finding all of the assessment reports in a given field is not an easy task. Proper evaluation of those assessments requires the conduct of a prospective experiment in which the sources and results are blinded when the choice is made of papers to exclude and to include, and the process should be carried out in duplicate. There are several available data bases for carrying out the search, but because of indexing problems they should be supplemented by reference to the bibliographies of pertinent published articles. Clinical trials included in meta-analyses should be graded by quality and thus facilitate sensitivity analyses. Attention must be paid to the possibility of publication bias. Finally, the advent of meta-analysis makes it desirable to begin randomized controlled trials in areas of uncertainty, even when there is no possibility that individual investigators will encounter enough patients to draw valid conclusions.

Clinical Trials as Topic↗
PubMed1989

A meta-analysis of randomized control trials of progestational agents in pregnancy.

The continued use of progestational agents in attempts to achieve a normal outcome of pregnancy in women with a 'high-risk' pregnancy (previous miscarriage, stillbirth or present preterm labour) prompted this meta-analysis of randomized control trials of such therapy. Of 20 trials of a progestogen 15 had combinable data. Combined comparisons, using odds ratios with confidence intervals, were made of the rates of livebirths at term or preterm and the sum of term and preterm deliveries, miscarriages, stillbirths and neonatal deaths. All but one comparison failed to show a significant benefit. Only the preterm delivery versus the term delivery comparison approached statistical significance. There were average deficiencies of quality apparent in the studies, and a test for heterogeneity among the studies was positive, but these caveats do not diminish the conclusion that progestogens should not be used outside of randomized trials at present. If trials are done, they should include only women with demonstrated hormonal abnormalities who are carrying a live fetus as shown by ultrasonography.

Abortion, Spontaneous↗
PubMed1989

Central nervous system infections in the elderly.

Review of records of patients aged 65 years and older admitted to The Mount Sinai Hospital, New York, NY, during the period from 1970 through 1985 revealed 57 episodes of central nervous system infections, including 50 meningitides, 5 brain abscesses, 1 subdural empyema, and 1 epidural abscess. Predisposing conditions were present in 17 patients with meningitis, and concurrent infections occurred in 19 patients. Streptococcus pneumoniae accounted for 43% of all isolates; 25% were gram-negative organisms. Of the patients in this sample, fever was present in 100%, meningismus was present in 58%, and change in mental status was present in 86%. Sixty-five percent of patients with meningitis survived; increased mortality was associated with altered mental status, inappropriate initial antibiotic therapy, and hypoglycorrhachia. Delay in diagnosis, underlying disease, and bacteremia did not significantly alter outcome. All patients with focal infections presented with localizing signs and all survived.

Aged↗
PubMed1989

Umbilical cord blood serosurvey for human immunodeficiency virus in parturient women in a voluntary hospital in New York City.

The potential spread of the human immunodeficiency virus (HIV) to childbearing women in areas of high acquired immunodeficiency syndrome (AIDS) endemicity is a major public health concern. As a private institution providing obstetric care to such a population of women, we undertook an anonymous HIV cord blood serosurvey to estimate the number of childbearing women at our institution at risk for perinatal transmission of the virus and to assess the success of our voluntary screening program to identify seropositive women. Between November 1987 and January 1988, cord blood samples from all clinic deliveries were analyzed for the presence of HIV antibody. For each sample obtained, the mother's age and site of prenatal care were known. Overall, 2.7% (six of 224) of the samples tested were seropositive; two of the 34 samples (5.9%) from teenage mothers were seropositive. All positive samples were from women who received prenatal care; none were identified through a voluntary screening program based on patient self-acknowledged risk-behavior assessment. This confirms that risk factor history elicited by personal interview is not a reliable screening tool for initiating HIV antibody counseling and testing. The high seropositive rate in teenagers is disturbing and needs further assessment.

AIDS Serodiagnosis↗
PubMed1988

The poor quality of early evaluations of magnetic resonance imaging.

To study the quality of early research on the clinical efficacy of diagnostic imaging with magnetic resonance, we assessed 54 evaluations published in the first four years after introduction of this modality using ten commonly accepted criteria of research methodology. The terms sensitivity, specificity, false-positive or false-negative, accuracy, and predictive values were used infrequently. Nineteen percent of the evaluations used three terms appropriately, 48% used one or two terms, and 33% used none. Data were presented appropriately for one or more of the five terms in 59% of evaluations. A "gold standard" comparison with the results of an independent procedure, such as surgical or autopsy findings, was presented in 22% of evaluations. Results of another imaging procedure were described in 63% of evaluations. Only one evaluation clearly described a prospective study design, although 11 evaluations apparently were planned in advance. Not one evaluation contained an appropriate statistical analysis of the distributions of quantitative readings, "blinded" image readers to diagnosis or other test results, measured observer error, or randomized the order of magnetic resonance imaging and other imaging procedures. We conclude that health care professionals paying for expensive innovative diagnostic technology should demand better research on diagnostic efficacy.

Evaluation Studies as Topic↗
PubMed1988

Meta-analysis of clinical trials: summary of an international conference.

An international conference of clinicians, clinical investigators and biostatisticians discussed meta-analysis in relation to clinical trials, i.e. the combination of data from separate studies for the purpose of obtaining information that cannot be derived from the individual studies. Meta-analysis can be a helpful tool for generating hypotheses for future trials, for studying the consistency of trials of the same or similar goals, and for generating more precise estimates of effect. There are still a number of unresolved questions about the methodology and interpretation of meta-analysis. Better and more uniform reporting of primary studies would increase the usefulness of meta-analysis.

Clinical Trials as Topic↗
PubMed1988

Dipyridamole in the treatment of angina pectoris: a meta-analysis.

A meta-analysis was performed to reevaluate the efficacy of dipyridamole for prophylaxis of angina pectoris. We found 10 articles that reported 11 randomized control trials published between 1960 and 1970. Three trials found a statistically significant benefit for the drug vs placebo, four showed a positive trend, two found no difference, and two showed a slight trend favoring placebo. When the results of all 11 trials were combined, two different statistical methods showed a statistically significant benefit from the drug. These combined results must be interpreted cautiously because of excluded patients and other methodologic variations in the studies, as well as evidence from other studies that dipyridamole may aggravate angina. Nevertheless, we conclude that there is some evidence for efficacy of the drug and believe the question should be restudied in larger and better-designed trials.

Angina Pectoris↗
PubMed1988

Antiplatelet agents in the secondary prevention of stroke: meta-analysis of the randomized control trials.

Randomized control trials of antiplatelet agents in the prevention of stroke following transient ischemic attacks have had conflicting results. The decision to employ aspirin instead of placebo as the control regimen in trials testing newer antiplatelet agents emphasizes the need for an accurate estimate of the efficacy of older drugs. A meta-analysis of seven randomized control trials comparing aspirin and/or sulfinpyrazone or dipyridamole with placebo was performed. For aspirin compared with placebo, a nonsignificant reduction in stroke of 15% (odds ratio 0.85, 95% confidence interval 0.60-1.19; chi 2 = 0.78, p greater than 0.30) was found. For aspirin combined with sulfinpyrazone or dipyridamole compared with placebo, a 39% reduction in stroke was observed (odds ratio 0.61, 95% confidence interval 0.39-0.95; chi 2 = 4.22, p less than 0.05); at the same time a 350% increase in gastrointestinal hemorrhage or peptic ulcer was noted (odds ratio 3.5, 95% confidence interval 1.26-9.75; chi 2 = 4.61, p less than 0.05). A trend in reduction of strokes for men was observed (odds ratio 0.58, 95% confidence interval 0.32-1.07; chi 2 = 2.52, p less than 0.15) for any regimen containing aspirin. The significant benefit of aspirin-combination therapy on stroke must be interpreted cautiously because of a number of possible biases. It is still conceivable that aspirin alone may decrease the incidence of stroke by as much as 40%, but a sample of greater than 13,000 patients would be needed to confirm the benefit observed in our analysis.

Aspirin↗
PubMed1987

Meta-analysis of randomised controlled trials of nicotine chewing-gum.

A meta-analysis was made of fourteen randomised controlled trials that evaluated the efficacy of nicotine chewing-gum in stopping patients smoking. The combined success rates in specialised cessation clinics are significantly higher with nicotine gum (27%) than with placebo gum (18%) at 6 months (n = 734), and 23% and 13% at 12 months, respectively. In contrast, success rates in general medical practices are similar with nicotine gum (11.4%) and with placebo gum (11.7%) at 6 months (n = 1022). However, in general practices, the success rates are 17% for nicotine gum and 13% for the no gum control at 4-6 months, and 9% and 5% at 12 months, a significant difference between the treatments at each time (n = 2238). The data suggest that proper use of nicotine gum in specialised clinics will increase the rate of stopping patients smoking. The use of the gum in general medical practices is questionable.

Carbon Monoxide↗
PubMed1987

Meta-analyses of randomized controlled trials.

A new type of research, termed meta-analysis, attempts to analyze and combine the results of previous reports. We found 86 meta-analyses of reports of randomized controlled trials in the English-language literature. We evaluated the quality of these meta-analyses, using a scoring method that considered 23 items in six major areas--study design, combinability, control of bias, statistical analysis, sensitivity analysis, and application of results. Only 24 meta-analyses (28 percent) addressed all six areas, 31 (36 percent) addressed five, 25 (29 percent) addressed four, 5 (6 percent) addressed three, and 1 (1 percent) addressed two. Of the 23 individual items, between 1 and 14 were addressed satisfactorily (mean +/- SD, 7.7 +/- 2.7). We conclude that an urgent need exists for improved methods in literature searching, quality evaluation of trials, and synthesizing of the results.

Clinical Trials as Topic↗
PubMed1987

Publication bias and clinical trials.

A study was performed to evaluate the extent to which the medical literature may be misleading as a result of selective publication of randomized clinical trials (RCTs) with results showing a statistically significant treatment effect. Three hundred eighteen authors of published trials were asked whether they had participated in any unpublished RCTs. The 156 respondents reported 271 unpublished and 1041 published trials. Of the 178 completed unpublished RCTs with a trend specified, 26 (14%) favored the new therapy compared to 423 of 767 (55%) published reports (p less than 0.001). For trials that were completed but not published, the major reasons for nonpublication were "negative" results and lack of interest. From the data provided, it appears that nonpublication was primarily a result of failure to write up and submit the trial results rather than rejection of submitted manuscripts. The results of this study imply the existence of a publication bias of importance both to meta-analysis and the interpretation of statistically significant positive trials.

Clinical Trials as Topic↗
PubMed1987

Medullary carcinoma of the thyroid, pancreatic nesidioblastosis and microadenosis, and pancreatic polypeptide hypersecretion: a new association and clinical and hormonal responses to long-acting somatostatin analog SMS 201-995.

We describe a 63-yr-old man with disseminated medullary carcinoma of the thyroid and pancreatic nesidioblastosis and microadenosis with pancreatic polypeptide (PP) hypersecretion. His major symptoms were watery diarrhea, flushing, and abdominal bloating; these and the elevated plasma PP levels did not change after resection of the distal two thirds of the pancreas, which contained a 2-cm mass of nesidioblastotic tissue. Postoperatively, a long-acting somatostatin analog, SMS 201-995 (100 micrograms/day), normalized PP secretion acutely and chronically (7 months) and ameliorated his symptoms. The analog had no side-effects and did not alter glucose tolerance, calcitonin hypersecretion, or growth of the medullary carcinoma, but it did inhibit GH secretion. After withdrawal from therapy for 1 month, PP hypersecretion and all symptoms except diarrhea recurred. The coexistence of medullary carcinoma of the thyroid and PP cell nesidioblastosis represents a new variant of the overlap syndromes between multiple endocrine neoplasia types I and II. Patients with medullary carcinoma and unexplained watery diarrhea should have fasting gastroenteropancreatic hormone assays done to screen for a potential gastrointestinal or pancreatic origin for the diarrhea.

Calcitonin↗
PubMed1986

Meningococcal pneumonia and empyema.

A case of pneumonia and empyema caused by Neisseria meningitidis is described in which the diagnosis was initially missed. Meningococcal pneumonia and empyema are rare. It is important to recognize unusual manifestations of meningococcal infection promptly because of the risk of spread to contacts including health care personnel and other patients.

Aged↗
PubMed1986

Loss of patients in clinical trials that measure long-term survival following myocardial infarction.

Loss of patients from clinical trials can nullify adequate randomization if the loss is unequally distributed among treatment groups. This study was designed to assess the magnitude of the problem in randomized control trials evaluating long-term therapy for survivors of myocardial infarction (MI). Only 19 of 52 trials reported having an explicit policy on withdrawals in the design stage; only 2 reported blinding the decision for withdrawal and only 7 reported accounting for withdrawals in sizing. In addition, only 16 gave the reader enough information to calculate the effect of withdrawals on trial results. In 2 of these 16 trials a p less than 0.05 result obtained by including withdrawals (intention to treat method) was reduced to p less than 0.05 when withdrawals were excluded. It is evident that many long-term trials do not contain adequate data on withdrawals. Readers of published trials are seldom able to judge whether or not withdrawals might affect the final results.

Clinical Trials as Topic↗