Early termination of the clinical trial
hypernatremia
HYPERNATREMIA
After recruiting the first 50 cases, an independent statistician performed the first interim analysis. A power of 0.09 was found, and a conditional power of 0.34 was calculated for the planned sample size. The 95% CI for the RR at this level would have been 0.99–1.27. The recalculation of the sample size at the same p and power, with the observed parameters, resulted in 1102 patients. With this information and the observation of a high proportion of patients developing hypernatremia in one of the groups, the data and safety monitoring board recommended stopping the trial.