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At least 19 recordsLinked to original sources
PubMed1992

Bioequivalence studies of topical preparations: statistical considerations.

To be approved for marketing, a potential generic pharmaceutical product must demonstrate bioequivalence, that is, a rate and extent of absorption similar to those of the currently marketed ("innovator") product. For oral products, design and statistical analysis for studies conducted to determine whether two products are bioequivalent have become reasonably standardized; the design is crossover, and analysis is based on the two one-sided tests principle. The purpose of this overview is to consider whether the practices for oral products apply to topical products, and where different procedures may be required. The principles behind the practices for oral products are seen, largely, to carry over to topical products.

Administration, Topical↗
PubMedDate not supplied

Selected topics in statistical analysis of clinical research.

Statistical analysis usually is employed in the evaluation of clinical research studies. This paper reviews and makes recommendations in three areas frequently overlooked in the conduct of clinical research: power analysis, specification of a priori research hypotheses, and Bayesian analysis. Power analysis determines the number of subjects required to conduct a meaningful study and should be performed during the planning phase. Research and null hypotheses are essential elements of research design and should be specified prior to statistical analysis. Bayesian analysis can be used both to evaluate diagnostic tests and as an alternative to traditional statistical approaches for testing multiple hypotheses. Application of these methods is described and clinical examples are provided. The discussion is nontechnical and is directed toward the clinical researcher.

Aged↗
PubMed1987

Review: clinical trials in peptic ulcer disease--problems of methodology and interpretation.

This review focuses on the methodology and interpretation of drug trials in peptic ulcer disease. The problems of planning and conduct that are discussed include the ethics of using placebo, eligibility criteria, estimations of sample size, stopping rules, randomization, blinding, and efficacy criteria, that is, ulcer healing and pain relief in the short term and prevention of relapse and complications in the long term. Statistical topics covered include confidence intervals, evaluation of survival type data, post-stratification, and sub-group analysis. The difference between clinical and statistical significance is discussed, major problems being overemphasis on P-value, type II errors, and post hoc power determinations. Explanatory and pragmatic questions are based on compliance-to-protocol and intention-to-treat cohorts, respectively, and involve problems of compliance testing, evaluation of withdrawals, and the use of fixed-dose regimens. The rather slow process for clinical trials to gain acceptance is described, and it is proposed to rely on disease-related and behavioural barriers, lack of knowledge of the inherent limitations of methodology, and overemphasis on the subject of peptic ulcer healing, in addition to some concern at the relevance of assessing long-term drug intervention by repeated endoscopies rather than by studying symptoms and the incidence of complications. We foresee an increased impact of clinical trials on ulcer research and therapeutic decision making, provided physicians are able to develop the proper methodology to answer the relevant questions.

Anti-Ulcer Agents↗
PubMed1981

Quantification of protease, amylase and lipase in the gut of Schizodactylus monstrosus during the postembryonic developmental stage. Effect of starvation, stress and topical application of juvenile hormone analogue.

A quantitative picture is presented on the activities and distribution of three major digestive enzymes in the postembryonic and adult stages of Schizodactylus monstrosus. The activity of enzymes in adult insects of both sexes has also been studied under starvation stress and after the topical application of juvenile hormone analogue. Results show that amylase activity was much higher in the early stages of development while in later stages protease and lipase activity was more significant. Protease activity was highest in the adult male, while the activity of all the enzymes reached its maximum in pregnant females. Starvation stress in adult individuals led to a slight decline of enzyme activity which was insignificant statistically. Topical application of JHa in high doses caused a steady increase in the activity of all the enzymes of which the increase of protease was statistically significant. The probable reasons for the quantitative variation have been discussed.

Administration, Topical↗
PubMed1990

Efficacy of prism adaptation in the surgical management of acquired esotropia. Prism Adaptation Study Research Group.

Prism adaptation, the preoperative use of prisms in acquired esotropia to determine the maximum angle of strabismus and to estimate fusional potential, has been suggested as a method of improving the results of initial surgery and minimizing the rate of reoperation. We performed a prospective, randomized, multicenter clinical trial of the effectiveness of prism adaptation. Two levels of randomization were used. Sixty percent of the patients underwent prism adaptation and 40% did not. Of those who responded to prisms with motor stability and sensory fusion, half underwent a conventional amount of surgery and half underwent augmented surgery based on the prism-adapted angle of deviation. Success rates were highest (54 [89%] of 61 patients) in prism adaptation responders who underwent augmented surgery and lowest (92 [72%] of 127 patients) in patients who did not undergo prism adaptation. Prism responders had better results with augmented surgery than with conventional surgery (54 [89%] of 61 patients vs 53 [79%] of 67 patients, P = .23). Our results indicated a significant beneficial overall effect of prism adaptation in patients with acquired esotropia (success rates, 83% vs 72%, P = .04). Although the process requires some additional time and effort, it appears to result in a higher rate of satisfactory alignment.

Adaptation, Ocular↗
PubMed1989

Can the provision of information to patients with osteoarthritis improve functional status? A randomized, controlled trial.

After we assessed the functional status of 439 patients with osteoarthritis, we randomly assigned them to 1 of 3 intervention groups or to a control group. The interventions consisted of providing information, and differed only in the method of delivery: by phone, in person at the clinic, or both. Physical health improved (P = 0.02), pain was reduced (P = 0.02), and psychological health improved marginally (P = 0.10) in patients contacted by phone compared with those not contacted by phone. In those contacted only at the clinic, physical health worsened (P = 0.02), but neither pain (P = 0.80) nor psychological health (P = 0.90) differed from the values in patients not contacted at the clinic. We conclude that telephone contact is a useful intervention that can enhance the functional status of patients with osteoarthritis.

Consumer Behavior↗
PubMed1985

Using economic analysis to determine the resource consequences of choices made in planning clinical trials.

In the planning stages of a clinical trial, investigators and funding agencies must make decisions which affect the conduct of those trials. One such decision concerns the choice of the minimum difference in outcomes between experimental and control therapies which would be considered clinically important, a variable which is used to calculate the sample size requirement. This choice is often determined by arbitrary rules-of-thumb. In order to make explicit the resource implications of such arbitrary choices this paper describes a cost-effectiveness model which determines the consequences (in resource allocation terms) of attempting to demonstrate smaller differences in outcomes. Incorporating economic principles into the decision making process in planning clinical trials may be helpful in allowing investigators and funding agencies to set priorities when allocating funds across trials competing for a fixed research budget.

Clinical Trials as Topic↗
PubMed1990

Ultrasound screening and perinatal mortality: controlled trial of systematic one-stage screening in pregnancy. The Helsinki Ultrasound Trial.

During a 19-month period, 95% of all pregnant women in the greater Helsinki area, Finland, entered a study to compare one-stage ultrasonography screening with selective screening according to antenatal hospital use, obstetric procedures, and fetal outcomes. Of 9310 women who entered the trial, 4691 were randomly allocated to ultrasound screening between the 16th and 20th gestational weeks and 4619 to follow-up only. Screened and control groups otherwise had the same antenatal care, which included ultrasonography according to usual practice. Screened women made fewer visits to the antenatal outpatient clinic than did women in the control group (2.3 vs 2.6). There were no differences in the number of labour inductions or mean birthweights in the two groups. Perinatal mortality was significantly lower in the screened than in the control group (4.6/1000 vs 9.0/1000); this 49.2% reduction was mainly due to improved early detection of major malformations which led to induced abortion. All twin pregnancies were detected before the 21st gestational week in the screening group compared with 76.3% in the control group; perinatal mortality in the small series of twins was 27.8/1000 vs 65.8/1000, respectively.

Evaluation Studies as Topic↗