In Reply We agree with Dr Hou and colleagues that it would be informative to determine the degree of sleep deprivation among physicians in our study; however, our databases do not allow us to identify the actual duration of sleep opportunity.
The subgroup analysis by Rothschild et al1 (Table 6) is interesting in that those surgeons who operated at night but had more than 6 hours of sleep opportunity had a lower complication rate (3.1%) than the surgeons in the control group from the primary analysis who did not operate at all the night before (7.1%). Whether this result reached statistical significance when adjusted for age, sex, and comorbidities was not published; however, a simple 2-by-2 contingency table analysis suggests that it did. Thus, it may not be accurate to conclude that this study showed that sleep opportunity has a significant association with complication rates.
Vinden C, Nash D. Next-Day Surgical Complications After Nighttime Procedures—Reply. JAMA. 2014;311(8):861-862. doi:10.1001/jama.2014.333