Severity of Sleep Interference Due to Neuropathic Pain May Be Predictive of Response to Pregabalin

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

Identification of baseline patient characteristics that predict therapeutic response to a specific drug may help guide treatment selection when choosing among multiple options. Bruce Parsons, MD, PhD, from Pfizer, New York, NY, and colleagues performed a post-hoc analysis to examine the relationship between severity of sleep interference scores at baseline and the magnitude of pregabalin-mediated pain reduction at endpoint in patients with painful DPN or PHN.

Investigators pooled data from 15 randomized, double-blind, placebo-controlled trials (range: 5–13 weeks duration) of pregabalin for the treatment of DPN or PHN. A total of 4,126 patients were evaluated and grouped according to diagnosis. The majority of the patients were male (DPN=58%; PHN=50%); mean age was 59.5 years for the DPN cohort and 70.0 years for the PHN cohort.

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

Among patients with DPN, significantly greater pain reduction at endpoint was observed for those receiving pregabalin and greater pain reduction occurred in patients with more severe sleep interference. In patients with severe, moderate, or mild sleep disturbance, 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 patients with PHN, pain reduction at endpoint was significantly greater for those receiving pregabalin and greater pain reduction occurred in patients with severe sleep disturbance. In patients with severe, moderate, or mild sleep disturbance, 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 pregabalin significantly improved sleep interference compared with placebo in both DPN (-1.00; P<0.001) and PHN (-1.06; P<0.001) populations; a majority of the sleep improvement in patients with DPN (62.0%) or PHN (62.4%) resulted from an indirect effect of pregabalin on pain.

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