Search

To investigate single and combined effects of daily dietary supplementation with 50 mg of vitamin B6 and 200 mg magnesium (as MgO) for one cycle for the relief of mild premenstrual symptoms, a randomized, double-blind, placebo-controlled, crossover design was used. Forty-four women with an average age of 32 years took part in the study. Each woman was randomly assigned, according to a Latin square design, to take consecutively all four of the following treatments daily for one menstrual cycle: (1) 200 mg Mg, (2) 50 mg vitamin B6, (3) 200 mg Mg + 50 mg vitamin B6 and (4) placebo. Throughout the study, each volunteer kept a daily record of symptoms using a 5-point ordinal scale in a menstrual diary of 30 symptoms. Symptoms were grouped into six categories: anxiety, craving, depression, hydration, other, and total. Urinary magnesium output for 24 hours was estimated using the Mg/creatinine concentration ratio. ANOVA showed no overall difference between individual treatments, but predefined treatment comparisons using factorial contrasts in ANOVA showed a significant effect of 200 mg/day Mg + 50 mg/day vitamin B6 on reducing anxiety-related premenstrual symptoms (nervous tension, mood swings, irritability, or anxiety) (p = 0.040). Urinary Mg output was not affected by treatment. A small synergistic effect of a daily dietary supplementation with a combination of Mg + vitamin B6 in the reduction of mild premenstrual anxiety-related symptoms was demonstrated during treatment of 44 women for one menstrual cycle. In view of the modest effect found, further studies are needed before making general recommendations for the treatment of premenstrual symptoms. The study indicated that absorption from MgO was poor and daily supplementation for longer than 1 month is necessary for tissue repletion. [ABSTRACT FROM AUTHOR]

The International Citicoline Trial in acUte Stroke is a sequential phase III study of the use of the drug citicoline in the treatment of acute ischaemic stroke, which was initiated in 2006 in 56 treatment centres. The primary objective of the trial is to demonstrate improved recovery of patients randomized to citicoline relative to those randomized to placebo after 12 weeks of follow-up. The primary analysis will take the form of a global test combining the dichotomized results of assessments on three well-established scales: the Barthel Index, the modified Rankin scale and the National Institutes of Health Stroke Scale. This approach was previously used in the analysis of the influential National Institute of Neurological Disorders and Stroke trial of recombinant tissue plasminogen activator in stroke.The purpose of this paper is to describe how this trial was designed, and in particular how the simultaneous objectives of taking into account three assessment scales, performing a series of interim analyses and conducting treatment allocation and adjusting the analyses to account for prognostic factors, including more than 50 treatment centres, were addressed., (Copyright 2008 John Wiley & Sons, Ltd.)

In clinical trials with a long period of time between randomization and the primary assessment of the patient, the same assessments are often undertaken at intermediate times. When an interim analysis is conducted, in addition to the patients who have completed the primary assessment, there will be those who have till then undergone only intermediate assessments. The efficiency of the interim analysis can be increased by the inclusion of data from these additional patients. This paper compares four methods of increasing information based on model-free estimates of transition probabilities to incorporate intermediate assessments from patients who have not completed the trial. It is assumed that the observations are binary and that there is one intermediate assessment. The methods are the score and Wald approaches, each with the log-odds ratio and probability difference parameterizations. Simulations show that all four approaches have good properties in moderate to large sample sizes.

Formal safety monitoring procedures are well-developed for use in individual clinical trials and provide valuable guidance to Independent Data Monitoring Committees (IDMCs). Less has been written about procedures for use over the whole of a drug development program. It is becoming common for a single IDMC to be appointed for a whole series of studies involving a single compound. While each study will have its own goals in terms of efficacy, safety, or both, there is the potential for all of them to contribute to an emerging picture of safety. Indeed, an IDMC overseeing several studies will need to integrate the data coming from each and a formal pre-defined approach can be a valuable aid. Formal procedures are especially relevant in situations where one or two undesirable events are recognized from the outset as being of particular concern. In some cases this might be death, and in the example discussed here it is a cardiovascular event of the type that has been found to be related to certain COX-2 inhibitors. In this paper a design proposal for a safety monitoring procedure for use by an IDMC during the development of a new COX-2 inhibitor will be described.

In this paper a robust method is developed for the analysis of data consisting of repeated binary observations taken at up to three fixed time points on each subject. The primary objective is to compare outcomes at the last time point, using earlier observations to predict this for subjects with incomplete records. A score test is derived. The method is developed for application to sequential clinical trials, as at interim analyses there will be many incomplete records occurring in non-informative patterns. Motivation for the methodology comes from experience with clinical trials in stroke and head injury, and data from one such trial is used to illustrate the approach. Extensions to more than three time points and to allow for stratification are discussed.

While planning the GAIN International Study of gavestinel in acute stroke, a sequential triangular test was proposed but not implemented. Before the trial commenced it was agreed to evaluate the sequential design retrospectively to evaluate the differences in the resulting analyses, trial durations and sample sizes in order to assess the potential of sequential procedures for future stroke trials. This paper presents four sequential reconstructions of the GAIN study made under various scenarios. For the data as observed, the sequential design would have reduced the trial sample size by 234 patients and shortened its duration by 3 or 4 months. Had the study not achieved a recruitment rate that far exceeded expectation, the advantages of the sequential design would have been much greater. Sequential designs appear to be an attractive option for trials in stroke., (Copyright 2004 S. Karger AG, Basel)

In a sequential clinical trial, accrual of data on patients often continues after the stopping criterion for the study has been met. This is termed "overrunning." Overrunning occurs mainly when the primary response from each patient is measured after some extended observation period. The objective of this article is to compare two methods of allowing for overrunning. In particular, simulation studies are reported that assess the two procedures in terms of how well they maintain the intended type I error rate. The effect on power resulting from the incorporation of "overrunning data" using the two procedures is evaluated.

We carried out a randomized, double-blind, crossover study of 85 women, designed to investigate the dose-response of daily Mg supplementation on premenstrual symptoms. Each woman took one of four treatments: Mg (200, 350 or 500 mg/day) or sorbitol (placebo) for 2 months. This was followed by a washout of 1 month, and then each woman received one of the three remaining treatments for a further 2 months. Unexpectedly, sorbitol (1305 mg) reduced anxiety-related and total premenstrual symptoms after 2 months compared with Mg treatments (P<0.001 and P<0.001, respectively). We conclude that low-dose sorbitol reduces premenstrual symptoms beyond that expected of a placebo. After 2 months of treatment, sorbitol also reduced urinary Mg excretion compared to baseline (no intervention) and Mg treatments (P=0.005). A follow-up study on 17 healthy volunteers confirmed lack of effect on urinary Mg output of a similar sorbitol intervention regime compared with either baseline or cellulose placebo. It appears that sorbitol may influence Mg homeostasis in women suffering premenstrual symptoms, but not in healthy individuals. Implications for placebo choice in RCTs are discussed., (Copyright 2002, Elsevier Science Ltd. All rights reserved.)