This process ensures the preservation of the benefits of randomization and avoids the introduction of bias during analysis. As-treated analysis may sometimes be used to test the robustness of findings but should rarely be used to replace the

use of intention-to-treat analysis. In the study by MG-132 nmr Suki et al.,1 as almost half of the study participants discontinued the study for a range of reasons such as non-compliance, loss to follow-up and adverse events, it was particularly important to include this proportion in the analyses so as to prevent overestimation of the treatment effect. Based on the results presented in the article, you are confident that the study has undertaken analyses according to the original randomization of participants, this website that is, by intention-to-treat. Questions: What were the results? What was the size and precision of the effect? When considering the results of a study, an assessment of the precision is essential. The exact ‘true’ effect of an intervention is never known. However, it is possible to estimate this effect.

When we consider the precision of a study, we are considering the proximity of an estimate to the ‘true’ effect. The interval, enclosed by the extremes at which the estimate may possibly lie, is known as the 95% confidence intervals (CIs). By accepting the 95% CI, one is accepting that the true effect lies within that range 95% of the time, in other words, the estimate will lie outside the interval 5% of the time. The precision of a study ultimately depends on the number of events, and therefore its sample size. As a general rule of thumb, the larger the proportion of participants who experience the outcome, the greater the precision, that is, total number of events drives the power of the study whilst the sample size and event rate determines Fenbendazole the total number of events. A larger sample size will produce more outcomes

and therefore narrower CIs, allowing one to be more confident that the estimate is closer to the true effect. The results of a study can be expressed in a number of different ways and it is important to understand and interpret the significance of such results. Some examples include differences in a continuous factor (e.g. effects of sevelamer on serum phosphate levels), a dichotomous outcome (e.g. relative risk of hyperphosphataemia or risk of cardiovascular events) or as time-to-event analyses, comparing the length of time taken for a particular event of interest to occur between the two groups, thus providing additional information and statistical power.8 The results of time-to-event analyses are often expressed by hazard ratios.9 Perhaps the most important method for presenting the results of dichotomous outcomes is the absolute risk difference, which describes the proportion of individuals prevented from having an event, and can be used to calculate numbers needed to treat.