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Biomedical subjects

D G Altman

Publications and source records attributed to D G Altman.

At least 145 records · Page 8Linked to original sources
PubMed1995

Aflatoxin and outcome from acute lower respiratory infection in children in The Philippines.

Aflatoxin is immunosuppressive in experimental conditions. This study addressed its potentially contributory role in the poor outcome of acute lower respiratory infections (ALRI) in children in The Philippines. The catchment area included peri-urban slums and middle-class housing. One hundred and fifteen children (mean age 2.1, range 0.08-12 years) were enrolled and their serum and urine obtained at presentation with ALRI. Aflatoxins in serum and aflatoxin metabolites in urine were measured by previously validated ELISA tests. Using the 1986 WHO criteria for the severity of ALRI, 31% had mild, 12% moderate, 49% severe and 8% severe complicated pneumonia. Eighty of 97 (82%) chest radiographs were abnormal. Ninety per cent of the children were below average weight for age, using Filipino standards, with a mean of 79% (range 27-157%). Thirteen (11%) children died. Aflatoxin in their serum, reflecting recent ingestion, was detected in 33%, with a mean positive value of 462 pg/ml. Aflatoxin metabolites (reflecting chronic ingestion) were detected in 64 of 65 urines collected, with a mean value of 0.1-4.77ng/ml. None of the children with detectable serum aflatoxin died. Anorexia and impaired consciousness were strongly associated with a poor outcome (prolonged fever or death). There was a strong association between undetectable serum aflatoxin concentrations and death (p = 0.004), perhaps reflecting anorexia. There was no relationship between the concentration of urinary aflatoxin metabolites and outcome. Serum was also obtained from 29 mothers on admission and none contained detectable aflatoxin. As virtually all the children had evidence of exposure to aflatoxin, a potentially immunosuppressive role in the context of pneumonia cannot be excluded.

Aflatoxins↗
PubMed1995

Comparing two methods of clinical measurement: a personal history.

Despite the fundamental importance of measurement in medicine, studies which compare methods of clinical measurement are often analysed inappropriately and may thus come to incorrect conclusions. We explain the problems with the main methods used, notably correlation and regression, and describe the limits of agreement approach which we have proposed. We consider why incorrect methods are so widely used and describe our own experience in bringing this issue to the attention of medical researchers.

Clinical Medicine↗
PubMed1994

Matching.

Explore the source record for details and available documents.

Case-Control Studies↗
PubMed1994

Assessing the quality of randomization from reports of controlled trials published in obstetrics and gynecology journals.

OBJECTIVE: To assess the methodologic quality of approaches used to allocate participants to comparison groups in randomized controlled trials from one medical specialty. DESIGN: Survey of published, parallel group randomized controlled trials. DATA SOURCES: All 206 reports with allocation described as randomized from the 1990 and 1991 volumes of four journals of obstetrics and gynecology. MAIN OUTCOME MEASURES: Direct and indirect measures of the adequacy of randomization and baseline comparisons. RESULTS: Only 32% of the reports described an adequate method for generating a sequence of random numbers, and only 23% contained information showing that steps had been taken to conceal assignment until the point of treatment allocation. A mere 9% described both sequence generation and allocation concealment. In reports of trials that had apparently used unrestricted randomization, the differences in sample sizes between treatment and control groups were much smaller than would be expected due to chance. In reports of trials in which hypothesis tests had been used to compare baseline characteristics, only 2% of reported test results were statistically significant, lower than the expected rate of 5%. CONCLUSIONS: Proper randomization is required to generate unbiased comparison groups in controlled trials, yet the reports in these journals usually provided inadequate or unacceptable information on treatment allocation. Additional analyses suggest that nonrandom manipulation of comparison groups and selective reporting of baseline comparisons may have occurred.

Gynecology↗
PubMed1994

Transfer of technology from statistical journals to the biomedical literature. Past trends and future predictions.

OBJECTIVE: To investigate the speed of the transfer of new statistical methods into the medical literature and, on the basis of current data, to predict what methods medical journal editors should expect to see in the next decade. DESIGN: Influential statistical articles were identified and the time pattern of citations in the medical literature was ascertained. In addition, longitudinal studies of the statistical content of articles in medical journals were reviewed. MAIN OUTCOME MEASURES: Cumulative number of citations in medical journals of each article in the years after publication. RESULTS: Annual citations show some evidence of decreasing lag times between the introduction of new statistical methods and their appearance in medical journals. Newer technical innovations still typically take 4 to 6 years before they achieve 25 citations in the medical literature. Few methodological advances of the 1980s seem yet to have been widely cited in medical journals. Longitudinal studies indicate a large increase in the use of more complex statistical methods. CONCLUSIONS: Time trends suggest that technology diffusion has speeded up during the last 30 years, although there is still a lag of several years before medical citations begin to accrue. Journals should expect to see more articles using increasingly sophisticated methods. Medical journals may need to modify reviewing procedures to deal with articles using these complex new methods.

Forecasting↗
PubMed1994

Is there a case for an international medical scientific press council?

Serious abuse of editorial power is rarely publicized, but evidence that it occurs is accumulating. Authors who believe that they have been dealt with unfairly have little possibility of a hearing of their complaint, and cases cannot easily be publicized because of fears of legal action. We describe briefly three cases in which the alleged misdeeds indicate that there were legitimate questions that needed answers. In the first case, an editor republished a previously published article without the authors' permission (but stated the opposite), attacked it in an accompanying editorial, and then denied the authors the right of reply. The other cases concerned a commissioned review article that was plagiarized and an editor with an undisclosed vested interest. An appeal process is needed for authors who think that they are victims of editorial abuse of power. We suggest that the International Committee of Medical Journal Editors turn its attention to editorial misconduct and explore possible procedures for allowing authors' grievances to be heard and for possible sanctions if complaints are upheld. An International Medical Scientific Press Council might be established to produce a code of conduct for editors and a corresponding taxonomy of inappropriate editorial behavior.

Advisory Committees↗