Objective: This analysis evaluated changes in pain and pain-related sleep disturbance with extended-release tramadol (tramadol ER) in patients with moderate, chronic osteoarthritis pain, and the influence of pain reduction on pain-related sleep disturbance.
Methods: Data were obtained from a 12-week, randomized, double-blind, placebo-controlled, fixed-dose study of tramadol ER 100 mg, 200 mg, 300 mg, or 400 mg once daily. Subjects reported osteoarthritis pain intensity with a 100-mm visual analog scale (VAS; 0 = no pain, 100 = extreme pain). A Sleep Problems Index score from 0 to 100 mm (0 = never, 100 = always) was determined from the mean of three subject-reported scores of pain-related sleep disturbance.
Results: A total of 815 subjects received tramadol ER (all doses combined) and 205 received placebo. Mean pain reduction at 12 weeks was -30.4 mm and -21.5 mm for tramadol ER and placebo, respectively (p < 0.001). Tramadol ER-treated subjects were nearly twice as likely as placebo subjects to have clinically meaningful pain reduction at 12 weeks, defined as 30 mm or greater reduction (odds ratio [OR] = 1.84, P < 0.001) or 30% or greater reduction (OR = 1.95, P < 0.001) in pain. Clinically meaningful reduction of pain-related sleep disturbance at 12 weeks, defined as 16 mm or greater improvement on the Sleep Problems Index, was more common for tramadol ER than placebo (51% vs. 42%, respectively, p = 0.022). Pain reduction was associated with reduced pain-related sleep disturbance (R = 0.51). Study treatment was generally well tolerated. Possible limitations included homogeneity of pain scores at baseline and the effect of adverse events on sleep analyses.
Conclusions: In patients with chronic osteoarthritis pain, pain reduction is associated with decreased pain-related sleep disturbance.