Biomedical subjects

R T O'Neill

Publications and source records attributed to R T O'Neill.

3 recordsLinked to original sources

PubMed1990

Competing risk analysis of life table data: application to lifetime risk computation.

In this pedagogic note we propose to assess the safety of treatment in a clinical trial, or the effect of risk exposure in a chronic animal study, in terms of two lifetime risks. These risks are computable from life table type data and take into account the effects of competing risks. We first describe their computational procedures in detail to demonstrate the need for their implementation in a computer program. We then illustrate their practical application through use of the data obtained from an actual clinical study.

Health Status Indicators↗

PubMed1978

Case-control studies: a sequential approach.

A sequential approach to the design of a matched pair case-control study is proposed as an alternative to fixed sample plans when information on case-control pairs is acquired sequentially in time. The method described is that of Wald using the Sequential Probability Ratio Test (SPRT) for comparing two binomial populations. The test is an open, non-truncated procudure. Several tables are presented for the average sample numbers needed under the sequential plan and fixed sample plan for selected Type 1 and 2 errors, alternative relative risks of interest and exposure probabilities in case and controls. A hypothetical example is presented to illustrate the use of the method and discussion is given as to the possible advantages and disadvantages of the sequential approach to case-control studies.

Epidemiologic Methods↗

PubMed1978

A statistical procedure useful in evaluating time of onset and termination of response in clinical trials.

A statistical model jointly characterizing the onset and termination of treatment response of a subject over a fixed observed time period is presented. The model requires that the observations for each subject are made at a set of pre-selected time points during the observed time period. A useful index characterizing the probability of being in response is developed along with maximum likelihood estimates and variances. A likelihood ratio test is developed to simultaneously compare two treatment groups with respect to this index for all times. The proposed procedure is applied to a set of data from a clinical trial of two bronchodilator drugs from which our procedure is motivated.

Bronchodilator Agents↗