Zolpidem extended-release 12.5 mg associated with improvements in work performance in a 6-month randomized, placebo-controlled trial

Abstract

Background: Although most research on pharmacotherapy for chronic insomnia focuses on changes in sleep outcomes, the functional impact of treatment is also of great importance to patients, families, physicians, and employers.

Objective: To analyze changes in functioning at work (or work performance) among a subset of employed subjects (N = 752) from a 24-week, randomized, double-blind, placebo-controlled trial of zolpidem extended-release 12.5 mg taken nightly, at least 3 nights per week, by healthy adults with chronic insomnia.

Methods: Using 2 scales (Time Management and Work Output) from the Work Limitations Questionnaire (WLQ), subjects' health-related work limitations were evaluated at baseline, week 4, week 12, and week 24 (end of study) or premature discontinuation. To compare zolpidem extended-release 12.5 mg with placebo, within-group and between-group differences were analyzed and effect sizes were computed. The relationship of WLQ scores to scores on the Patient Global Impression, Item 1 (PGI-1), scale, the primary outcome measure for benefit to sleep, was also analyzed. Data were obtained from August 31, 2004 through January 6, 2006.

Results: Scores on both WLQ scales were substantially elevated at baseline in this population, reflecting impairment relative to healthy controls. The zolpidem extended-release 12.5 mg group had significantly greater improvement at all time points on the WLQ Time Management (P < 0.0001) and Work Output (P < 0.01) scales. Effect size analysis confirmed the clinical relevance of these improvements. Subjects rating their sleep as improved on the PGI-1 had significantly greater improvement on both WLQ scales at week 12 than did those who reported no benefit or worsening (P < 0.01).

Conclusions: Employed adults with chronic insomnia treated with zolpidem extended-release 12.5 mg experienced significantly improved work performance over 24 weeks.

Figure 1

Time Management scale scores at baseline, week 4, week 12, and week 24 (end of study or premature discontinuation). All comparisons vs. within-group baseline. Responses to the 5 items for the Time Management scale from the Work Limitations Questionnaire were rated as: “none of the time” (5 points); “a slight bit of the time” (4 points); “some of the time” (3 points); “most of the time” (2 points); or “all of the time” (1 point).

Figure 2

Output scale scores at baseline, week 4, week 12, and week 24 (end of study or premature discontinuation). All comparisons vs. within-group baseline. Responses to the 5 items for the Time Management scale from the Work Limitations Questionnaire were rated as: “none of the time” (5 points); “a slight bit of the time” (4 points); “some of the time” (3 points); “most of the time” (2 points); or “all of the time” (1 point).

Figure 3

Time Management scale vs. PGI-1 scores. Responses to the 5 items for the Time Management scale from the Work Limitations Questionnaire were rated as: “none of the time” (5 points); “a slight bit of the time” (4 points); “some of the time” (3 points); “most of the time” (2 points); or “all of the time” (1 point).

Figure 4

Output scale vs. PGI-1 scores. Responses to the 5 items for the Time Management scale from the Work Limitations Questionnaire were rated as: “none of the time” (5 points); “a slight bit of the time” (4 points); “some of the time” (3 points); “most of the time” (2 points); or “all of the time” (1 point).