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Biomedical subjects

P Armitage

Publications and source records attributed to P Armitage.

At least 55 records · Page 3Linked to original sources
PubMed1979

Therapeutic trial of intracisternal human tetanus immunoglobulin in clinical tetanus.

A trial has been conducted of the efficacy of human tetanus immunoglobulin (250 I U) administered intrathecally (intracisternally) in addition to standard treatment (equine antitoxin intravenously, penicillin, anticonvulsants). The trial was analysed sequentially and was stopped for 120 patients when there was no longer any chance of achieving a statistically significant difference in favour of intrathecal administration. The sequential plan was modified during the trial. A prognostic correlation was found between onset of the first symptom and admission to hospital.

Adult↗
PubMed1978

Prognosis in tetanus: Use of data from therapeutic trials.

There is a need in clinical tetanus for a simple prognostic classification for all patients at time of admission to the hospital. Data from three randomized clinical trials performed in India in the 1960s, which contained information on several prognostic variables for 1,385 patients, have been used to study different methods of prognosis. A logistic regression performed on the combined data from the trials suggested that the probability of death is related separately to the period of onset (the time from the first symptom to generalized reflex spasms), to the time from first symptom to admission to the hospital, and to the clinical assessment of severity of tetanus on admission; the effects of these variables have been studied by tabulation. A new system is proposed for assigning patients to three prognostic groups, defined by time from first symptom to admission and whether or not reflex spasms were present on admission to the hospital. The range of fatality rates is 10%--63%. Neonates are assigned to a separate group with a fatality rate of 72%. Other prognostic groupings are also explored in case it is felt that the above method relies too heavily on local arrangements for medical care.

Child, Preschool↗
PubMed1977

Design and analysis of randomized clinical trials requiring prolonged observation of each patient. II. analysis and examples.

Part I of this report appeared in the previous issue (Br. J. Cancer (1976) 34,585), and discussed the design of randomized clinical trials. Part II now describes efficient methods of analysis of randomized clinical trials in which we wish to compare the duration of survival (or the time until some other untoward event first occurs) among different groups of patients. It is intended to enable physicians without statistical training either to analyse such data themselves using life tables, the logrank test and retrospective stratification, or, when such analyses are presented, to appreciate them more critically, but the discussion may also be of interest to statisticians who have not yet specialized in clinical trial analyses.

Drug Evaluation↗
PubMed1976

Point and interval estimation in the combination of bioassay results.

A procedure for combining evidence from different biological assays is shown to be equivalent both to generalized least-squares and to maximum-likelihood estimation. By appropriate nesting of hypotheses, the likelihood function can be used to test the agreement between the assays and to obtain probability limits for the combined estimate of potency. The properties of these limits are examined, with particular reference to the situation, unusual but not impossible in practice, in which the values of relative potency that they define consist of several disjoint segments instead of a single interval. The connection with general theory of estimating linear functional relations is pointed out.

Biological Assay↗
PubMed1976

Design and analysis of randomized clinical trials requiring prolonged observation of each patient. I. Introduction and design.

The Medical Research Council has for some years encouraged collaborative clinical trials in leukaemia and other cancers, reporting the results in the medical literature. One unreported result which deserves such publication is the development of the expertise to design and analyse such trials. This report was prepared by a group of British and American statisticians, but it is intended for people without any statistical expertise. Part I, which appears in this issue, discusses the design of such trials; Part II, which will appear separately in the January 1977 issue of the Journal, gives full instructions for the statistical analysis of such trials by means of life tables and the logrank test, including a worked example, and discusses the interpretation of trial results, including brief reports of 2 particular trials. Both parts of this report are relevant to all clinical trials which study time to death, and wound be equally relevant to clinical trials which study time to other particular classes of untoward event: first stroke, perhaps, or first relapse, metastasis, disease recurrence, thrombosis, transplant rejection, or death from a particular cause. Part I, in this issue, collects together ideas that have mostly already appeared in the medical literature, but Part II, next month, is the first simple account yet published for non-statistical physicians of how to analyse efficiently data from clinical trials of survival duration. Such trials include the majority of all clinical trials of cancer therapy; in cancer trials,however, it may be preferable to use these statistical methods to study time to local recurrence of tumour, or to study time to detectable metastatic spread, in addition to studying total survival. Solid tumours can be staged at diagnosis; if this, or any other available information in some other disease is an important determinant of outcome, it can be used to make the overall logrank test for the whole heterogeneous trial population more sensitive, and more intuitively satisfactory, for it will then only be necessary to compare like with like, and not, by chance, Stage I with Stage III.

Clinical Trials as Topic↗
PubMed1976

National Health Survey Systems in the European community.

This paper is based on the report of a conference held in October 1975 to discuss the possibilities for collaborative action between countries of the European Community in conducting various forms of health survey. Health interview surveys offer the principal opportunity for such action, and it may be possible to incorporate health questions into multi-purpose international surveys. Health examination surveys are less likely to be developed widely in the immediate future. Hospital in-patient discharge records are collected routinely in many countries, and further international cooperation seems feasible. These possibilities are now being kept under continuous review by a working party.

Costs and Cost Analysis↗
PubMed1976

Hycanthone dose-response in treatment of schistosomiasis mansoni in St. Lucia.

Clinical trials of hycanthone (single intramuscular dose) were undertaken in schistosomiasis mansoni patients in St. Lucia at five dose levels: 3.0, 2.5, 2.0, 1.5, and 1.0 mg/kg body weight. The most common side effect, vomiting, decreased in frequency from 51% at the highest dose to 3% at the lowest; minor side effects showed a similar trend. Three fecal specimens were examined before and at 6 months after treatment by qualitative, quantitative, and hatching techniques. All dose levels caused reductions in egg excretion of 89 to 98%. Rates of cure (absence of eggs by all three methods) according to dose (descending), pretreatment egg output (0-19, 20-49, 50-399, 400+ eggs/ml feces), and age (0-7, 8-14, 15-29, 30+ years) were analyzed to estimate the effect of each variable if the others had been constant. For dose, the standardized percentage success rates were 53.9%, 62.0%, 51.2% 54.0%, and 27.4%; for egg output, 67.0%, 51.8%, 43.2%, and 21.7%; and for age, 25.2%, 34.5%, 59.3% and 57.4%. Logit regression analysis shows a significant difference in cure rate (a) between the lowest dose and all others, among which latter there was no difference, (b) between patients excreting 0 to 49 eggs/ml before treatment and those excreting 50+ eggs/ml, and (c) between the age groups 0 to 14 and 15+ years. All dose levels caused some regression in enlargement of liver or spleen. A dose of 1.5 to 2.0 mg/kg body weight is considered to be as effective as one of 3.0 mg/kg and more acceptable for a control program because of the marked reduction in side effects.

Adolescent↗