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Biomedical subjects

N Mantel

Publications and source records attributed to N Mantel.

152 records · Page 9Linked to original sources
PubMedDate not supplied

Stratified analysis of multivariate clinical data: application of a Mantel-Haenszel approach.

Laboratory determinations on children aged 6 to 10 years obtained over a 5-year period are analysed by a method described in detail for differentiating between children from exposed and control areas of Seveso, Italy. In the analysis, stratification is employed to distinguish the separate days of laboratory measurement. The analyses permit the study of differences based on all variables simultaneously as well as on each variable separately. Results are obtained for each individual year and for longer intervals of 2 successive years, 3 successive years, 4 successive years, and all 5 years. The results and some statistical aspects of the analysis are discussed.

Analysis of Variance↗
PubMedDate not supplied

Cautions on the use of medical databases.

The use of medical databases is tied in with the conduct of epidemiologic and clinical investigations. I expound the thesis that investigative results are frequently ambiguous and subject to a multiplicity of interpretations, some even diametrically opposed, and describe examples of such situations. For instance, the very fact that an agent is particularly safe may make it seem dangerous--the agent becomes the one of choice for high risk patients. Other topics include the use of models, including regression models, Cox's proportional hazard model, the search for epidemiologic interactions, ratio measures, and grouping effects.

Clinical Trials as Topic↗
PubMedDate not supplied

A study of three techniques for time-space clustering in Hodgkin's disease.

Three techniques for disease time-space clustering analysis, those of Knox, Mantel and Ederer-Myers-Mantel, were applied to simulated data so as to study their sensitivities. The simulated data corresponded to three alternative non-null models for the distribution, transmission and development of Hodgkin's disease (HD) which were formulated in accordance with the results of published studies. The results indicate that the three techniques may not be sufficiently sensitive to the clustering in a real data set of HD cases. Therefore, the inconclusive results obtained to date with regard to clustering of HD may be related to the low power of the statistical techniques employed.

Hodgkin Disease↗
PubMedDate not supplied

Medical registers as historical controls: analysis of an open clinical trial of inosiplex in subacute sclerosing panencephalitis.

Clinical trials of treatments for rare or fatal diseases must often use historical rather than randomized concurrent controls. Randomized trials may not be possible if (1) the number of patients available is quite small, (2) ethical considerations discourage the assignment of patients to control treatments known to be ineffective or (3) some evidence suggests that the proposed new treatment is substantially more effective than the control. We suggest that, when randomization is not feasible, adequately maintained medical registers can serve as a source of control patients. Investigators must pay careful attention to prognostic factors that might bias the results. However, statistical techniques for controlling such bias exist and, if these are properly employed, registry-derived historical controls can be used to evaluate the effectiveness of treatment.

Clinical Trials as Topic↗