Combining evidence from clinical trials.
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Clinical Trials as Topic↗
Biomedical subjects
R DerSimonian
Publications and source records attributed to R DerSimonian.
Changes in Connecticut hospital use rates: have small-area variations been affected?
This paper examines the extent to which changes (prospective payment, alternative delivery systems, etc.) in the hospital environment and the general decline in hospital days affect small-area variations in hospital use rates for 18 selected diagnoses in nine hospital service areas in Connecticut. After adjusting for coding changes between DRGs, we found that variation across the service areas did not, in general, differ for any one of the years 1981-86. In one instance (cardiac catheterization), however, we found that a DRG-specific change in knowledge and technology decreased the extent of small-area variation for that diagnosis.
Analysis of Variance↗
Meta-analysis in clinical trials.
This paper examines eight published reviews each reporting results from several related trials. Each review pools the results from the relevant trials in order to evaluate the efficacy of a certain treatment for a specified medical condition. These reviews lack consistent assessment of homogeneity of treatment effect before pooling. We discuss a random effects approach to combining evidence from a series of experiments comparing two treatments. This approach incorporates the heterogeneity of effects in the analysis of the overall treatment efficacy. The model can be extended to include relevant covariates which would reduce the heterogeneity and allow for more specific therapeutic recommendations. We suggest a simple noniterative procedure for characterizing the distribution of treatment effects in a series of studies.
Clinical Trials as Topic↗
Prognostic role of antibody reactivity to melanoma.
Antibody reactivity against cultured allogeneic melanoma Y-Mel 81:180 was studied in 43 patients who participated in an adjuvant trial for stage I and II melanoma. Serum samples were obtained at trial entry within 2 mo of definitive surgery. At the time of serum acquisition, all patients were free of disease by physical examination and routine radiologic and laboratory parameters. Serum antibody reactivity was tested for by protein A hemadsorption before and after acid dissociation and ultrafiltration of serum. We have previously shown that this technique for immune complex dissociation augments autologous antibody reactivity. Results of serum antibody reactivity were scored by an investigator blinded to the patient's clinical status. Of the 43 patients studied, 15 relapsed and 28 remained disease-free. At study entry, there were 25 stage I patients and 18 stage II patients. Breslow depth was 3.25 +/- 2.5 mm in relapse patients and 1.67 +/- 1.1 mm in disease-free patients. The presence and titer of antibody directed against melanoma in either native serum or serum dissociated from immune complexes was found to be associated with eventual relapse (P = 0.0001). When results were subgrouped by stage of disease, Breslow depth, and hypopigmentation, antibody reactivity was still correlated with eventual relapse. The incidence and titer of antibody reactivity against melanoma appears to be a new prognostic factor in predicting eventual disease recurrence.
Adult↗
Reporting on methods in clinical trials.
A clinical trial cannot be adequately interpreted without information about the methods used in the design of the study and the analysis of the results. To determine the frequency of reporting what we consider 11 important aspects of design and analysis, we surveyed all 67 clinical trials published in the New England Journal of Medicine, the Lancet, and the British Medical Journal from July through December 1979 and in the Journal of the American Medical Association from July 1979 through June 1980. Of all 11 items in the 67 trials published in all four journals, 56 per cent were clearly reported, 10 per cent were ambiguously mentioned, and 34 per cent were not reported at all. At least 80 per cent of the 67 trials reported information about statistical analyses, statistical methods used, and random allocation of subjects, yet only 19 per cent reported the method of randomization. Loss to follow-up was discussed in 79 per cent of the articles, treatment complications in 64 per cent, and admission of subjects before allocation in 57 per cent, but eligibility criteria for admission to the trial appeared in only 37 per cent. Although information about whether patients were blind to treatment was given in 55 per cent, information about whether there was blind assessment of outcome was reported in only 30 per cent. The statistical power of the trial to detect treatment effects was discussed in only 12 per cent of the articles. The clinical trials published in The New England Journal of Medicine reported 71 per cent of the 11 items, those in the Journal of the American Medical Association 63 per cent, those in the British Medical Journal 52 per cent, and those in the Lancet 46 per cent. These rates are significantly different (P less than 0.001). We recommend that editors improve the reporting of clinical trials by giving authors a list of the important items to be reported.
Biometry↗