Effect of Melatonin on Cognitive Function and Sleep in relation to Breast Cancer Surgery: A Randomized, Double-Blind, Placebo-Controlled Trial

Table 4

Sleep latency, number of awakenings, total sleep period, sleep efficiency, and VAS sleep quality for the melatonin versus placebo in the short-term perioperative and the long-term postoperative period.

	Short-term perioperative period*			Long-term postoperative period**
	Mean difference MEL-PLC	95% CI	value	Mean difference MEL-PLC	95% CI	value
Sleep latency (min)	−3.78		0.18	0.01		0.95
Number of awakenings	−0.29		0.34	−0.26		0.42
Total sleep period (min)	2.3		0.89	37.0		0.03
Sleep efficiency (%)	4.28		0.02	0.6		0.76
VAS sleep quality	−4.71		0.37	−0.78		0.87

Sleep diary data were calculated as a median for each patient in the 2 time periods. Bootstrapping was used to calculate confidence intervals for the means and values for the difference in means. This was performed using the “smean.cl.boot” function in the “Hmisc” library in R version 3.0.1 (R Foundation for Statistical Software, Vienna, Austria).
MEL: melatonin.
PLC: placebo.
CI: confidence interval.
Sleep efficiency = (TSP − latency − minutes awake)/(TSP)%.
VAS: visual analogue scale.
* includes only patients who completed the whole short-term sleep diary (3 days preoperatively to 8 days postoperatively) MEL, , and PLC, .
** includes only patients who completed the whole long-term sleep diary (2 to 12 weeks postoperatively) MEL, , and PLC, .