OBJECTIVE: To examine the impact of night-shift duration (≤9 hours or >9 hours) on efficacy and tolerability of armodafinil in patients with shift work disorder (SWD).
METHODS: This was a post hoc analysis of a 6 week, multicenter, randomized, double-blind, placebo-controlled, parallel-group study. Shift workers with diagnosed SWD and late-in-shift sleepiness (between 4 am and 8 am, including the commute home) received armodafinil 150 mg or placebo before their night shift.
RESULTS: Proportion of patients with at least minimal improvement in late-in-shift sleepiness, late-in-shift Clinical Global Impressions-Change (CGI-C) rating and Karolinska Sleepiness Scale (KSS), as well as overall Global Assessment of Functioning (GAF) scale and modified Sheehan Disability Scale (SDS-M), were assessed at baseline and final visit.
RESULTS: Of the 383 patients enrolled, 279 (73%) worked shifts ≤9 hours and 104 (27%) worked shifts >9 hours. A greater percentage of patients receiving armodafinil had at least minimal improvement in late-in-shift CGI-C (≤9 hours: 78% vs 60%, P = 0.0017; >9 hours: 77% vs 46%, P = 0.0020) regardless of shift duration. Armodafinil patients also demonstrated significantly greater improvements in GAF score (≤9 hours: 9.5 vs 5.4, P < 0.0001; >9 hours: 9.6 vs 4.3, P = 0.0019) and KSS score (≤9 hours: -2.9 vs -1.9, P = 0.0002; >9 hours: -2.8 vs -1.6, P = 0.00 28). Improvement in SDS-M composite score was significantly greater for armodafinil patients working >9 hours (-6.8 vs -2.7, P = 0.0086). Headache was the most frequent adverse event in all treatment groups.
CONCLUSIONS: Patients receiving armodafinil had significantly greater improvements in late-in-shift clinical condition and in wakefulness and overall global functioning than did placebo-treated patients, regardless of shift duration. Prospectively designed, randomized clinical trials that include objective measures of sleepiness are needed to support these findings.
