Statistical Methods in Recent HIV Noninferiority Trials: Reanalysis of 11 Trials

Background: In recent years the ‘‘noninferiority’ ’ trial has emerged as the new standard design for HIV drug development among antiretroviral patients often with a primary endpoint based on the difference in success rates between the two treatment groups. Different statistical methods have been introduced to provide confidence intervals for that difference. The main objective is to investigate whether the choice of the statistical method changes the conclusion of the trials. Methods: We presented 11 trials published in 2010 using a difference in proportions as the primary endpoint. In these trials, 5 different statistical methods have been used to estimate such confidence intervals. The five methods are described and applied to data from the 11 trials. The noninferiority of the new treatment is not demonstrated if the prespecified noninferiority margin it includes in the confidence interval of the treatment difference. Results: Results indicated that confidence intervals can be quite different according to the method used. In many situations, however, conclusions of the trials are not altered because point estimates of the treatment difference were too far from the prespecified noninferiority margins. Nevertheless, in few trials the use of different statistical methods led to different conclusions. In particular the use of ‘‘exact’ ’ methods can be very confusing. Conclusion: Statistical methods used to estimate confidence intervals in noninferiority trials have a strong impact on th

Facial electroneurography in Bell's palsy: variability in the early stage and comparison between interpretation methods Eletroneurografia do nervo facial na paralisia de Bell: variabilidade na fase aguda e comparação entre técnicas

To determine the variability of the abnormalities found in the electroneurography (ENG) of the facial nerve in cases of Bell's palsy during the initial two week period was one of the objectives of the authors. A second one was to investigate the value of ENG as a tool to determine an early prognosis of recovery utilizing two different methods. In the first one the amplitude of the compound muscular action potential (CMAP) obtained on the paralyzed side was compared to this potential on the opposite (normal) side. The second method compared the CMAP on the paralyzed side to normal standardized data from normal individuals. A group of 33 patients with Bell's palsy was followed until total recovery or for at least 4 months, if the recovery was not achieved earlier. It was observed that amplitude of the CMAP become stable towards the sixth day of palsy and this is a good time to establish the prognosis. Another conclusion is that both methods were equivalent to determine the prognosis in Bell's palsy.<br>O objetivo deste trabalho é determinar a variabilidade da eletroneurografia (ENG) do nervo facial na paralisia de Bell durante as primeiras duas semanas e investigar o valor da ENG na determinação de um prognóstico precoce utilizando-se dois métodos diferentes. O primeiro método compara a amplitude do potencial de ação muscular composto obtido no lado paralisado com o lado normal e o segundo método compara o potencial de ação muscular composto obtido no lado paralisado com valores normativos. Um grupo de 33 pacientes com paralisia de Bell foi seguido até a recuperação total ou pelo menos por quatro meses nos casos em que não houve recuperação. Observou-se que a amplitude do potencial de ação muscular composto estabiliza-se em torno do sexto dia e que este é um bom momento para se realizar o exame e se estabelecer um prognóstico. Outra conclusão é que ambos os métodos são equivalentes para determinação prognóstica