HONOLULU, HI—Severityof sleep disturbance in patients with painful diabetic peripheral neuropathy(DPN) or post-herpetic neuralgia (PHN) may be predictive of patient response topregabalin treatment for neuropathic pain reduction, a presentation at theAmerican Pain Society’s 31st Annual Scientific Meeting has found.

Identification of baselinepatient characteristics that predict therapeutic response to a specific drugmay help guide treatment selection when choosing among multiple options. BruceParsons, MD, PhD, from Pfizer, New York, NY, and colleagues performed apost-hoc analysis to examine the relationship between severity of sleepinterference scores at baseline and the magnitude of pregabalin-mediated painreduction at endpoint in patients with painful DPN or PHN.

Investigators pooled data from15 randomized, double-blind, placebo-controlled trials (range: 5–13 weeksduration) of pregabalin for the treatment of DPN or PHN. A total of 4,126patients were evaluated and grouped according to diagnosis. The majority of thepatients were male (DPN=58%; PHN=50%); mean age was 59.5 years for the DPNcohort and 70.0 years for the PHN cohort.

Severity of sleepinterference was based on an 11-point Daily Sleep Interference scale andcharacterized as mild (<4), moderate (4–7), or severe (>7). Daily painscores were measured using an 11-point scale and were recorded by the patientsin pain diaries. The change in mean pain score at endpoint was analyzed foreach cohort using an analysis of covariance interaction model.

Among patients with DPN,significantly greater pain reduction at endpoint was observed for thosereceiving pregabalin and greater pain reduction occurred in patients with moresevere sleep interference. In patients with severe, moderate, or mild sleepdisturbance, improvements in pain scores over placebo of -1.14 (P<0.001), -0.73 (P<0.001), and -0.51 (P=0.001),respectively, were observed.

Likewise, among patientswith PHN, pain reduction at endpoint was significantly greater for thosereceiving pregabalin and greater pain reduction occurred in patients withsevere sleep disturbance. In patients with severe, moderate, or mild sleepdisturbance, improvements over in pain scores over placebo of -1.55 (P<0.001), -0.98 (P<0.001), and -0.99 (P<0.001),respectively, were observed.

Treatment with pregabalinsignificantly improved sleep interference compared with placebo in both DPN(-1.00; P<0.001) and PHN (-1.06; P<0.001) populations; a majority ofthe sleep improvement in patients with DPN (62.0%) or PHN (62.4%) resulted froman indirect effect of pregabalin on pain.

Dr.Parsons stated the findings of the analysis suggest that patients with DPN orPHN presenting at baseline with more severe levels of sleep disturbance arelikely to be more responsive to treatment with pregabalin and report more painreduction. Therefore, “high levels of baseline sleep interference may be usefulfor identifying patients with DPN or PHN who are likely to respond well topregabalin treatment for the management of pain,” he concluded.