Mean analgesic consumption is inappropriate for testing analgesic efficacy in post-operative pain: analysis and alternative suggestion.

Background And Objective: Post-operative analgesic consumption is often used as a surrogate measure for pain; analyses of mean data assume a Gaussian distribution and use parametric statistics to assess statistical differences, often in small samples. We used a large individual patient dataset to examine the distribution of analgesic consumption, the validity of such analyses and alternative dichotomous outcomes.

Methods: Analysis of individual patient data from 913 patients over 48 post-operative hours in five randomised trials.