To the Editor:

Hudetz and colleagues report the effect of metabolic syndrome on postoperative cognitive dysfunction after noncardiac surgery [1]. A sample-size estimate was not provided to justify the choice of 30 patients per group, which is considerably smaller than is typical for trials evaluating posopterative cognitive function.

The primary outcome is not defined, but one of two reported positive outcomes is that “the prevalence rate of postoperative cognitive dysfunction differed in the studied groups (13/30 and 8/30) in patients with versus without metabolic syndrome; P < 0.02.” The actual P value for these proportions is 0.176, a value that is well above the author’s threshold for statistical significance, which was 0.05.