For common outcomes there was similar efficacy between PDE-5 inhibitors
Background There are no r and omised and properly blinded trials directly comparing one PDE-5 inhibitor with another in a normal home setting .
Valid indirect comparisons with a common comparator must examine equivalent doses , similar duration , similar population s , with the same outcomes reported in the same way .
Empirical evidence of bias in infertility research: overestimation of treatment effect in crossover trials using pregnancy as the outcome measure.
OBJECTIVE To determine whether crossover trials with simple pooling of data over different study periods leads to a different estimate of treatment effect compared with parallel group trials in infertility research using pregnancy as the outcome measure . DESIGN An observational study using nine overviews that included trials with both crossover and parallel group design s. These overviews comprised 17 crossover and 17 parallel group trials . In total , there were 5,291 outcomes including 775 pregnancies . The association between study design and treatment effect estimate was analyzed using multiple logistic regression , controlling for differences in the therapeutic interventions and variations in the method ological quality of the trials . SETTING Infertile patients in an academic research environment . PATIENTS Infertile patients undergoing treatment efficacy evaluation in controlled trials . INTERVENTIONS R and om allocation to a variety of treatments including clomiphene citrate , hCG , IUI , tamoxifen , and bromocriptine . MAIN OUTCOME MEASURE Estimate of bias between study design s , based on the interaction of study design and treatment in the logistic regression model . RESULTS Crossover trials produced a larger average estimate of treatment effect compared with trials with a parallel group design , overestimating the odds ratio by 74 % ( 95 % confidence interval , 2 % to 197 % ) . CONCLUSION The use of a crossover design for evaluating infertility treatments with outcomes that prevent patients from completing later phases of the trial should be avoided because it leads to exaggerated estimates of treatment effect and may result in erroneous inferences and clinical decisions . Furthermore , the type of study design should be taken into account when assessing the method ological quality of therapy trials in infertility
For common outcomes there was similar efficacy between PDE-5 inhibitors
Background There are no r and omised and properly blinded trials directly comparing one PDE-5 inhibitor with another in a normal home setting .
Valid indirect comparisons with a common comparator must examine equivalent doses , similar duration , similar population s , with the same outcomes reported in the same way .