The efficacy of pregabalin in patients with moderate and severe pain due to diabetic peripheral neuropathy

Objective To compare the therapeutic response to pregabalin in patients with moderate or severe painful diabetic peripheral neuropathy (pDPN). Research design and methods Data were pooled from 11 placebo-controlled trials to evaluate the efficacy of pregabalin flexible or fixed dose (150, 300 or 600mg/day) in pDPN patients with mean baseline pain scores of >= 4 to <7 (moderate) or >= 7 to <= 10 (severe). Last observation carried forward imputation was used. Study number/ClinicalTrials.gov identifier 1008-014/-, 1008-029/-, 1008-040/-, 1008-131/-, 1008-149/-, 1008-000-155/-, A0081030/NCT00156078, A0081060/NCT00159679, A0081071/NCT00143156, A0081081/NCT00301223, A0081163/NCT00553475. Main outcome measures Pregabalin-mediated change in pain, pain-related sleep interference (PRSI) and patient global impression of change (PGIC) were compared versus placebo and between moderate and severe pain cohorts. Adverse events (AEs) were reported. Results At baseline, 1816 patients had moderate pain (pregabalin, n = 1189) and 1119 patients had severe pain (pregabalin, n = 720). Pregabalin significantly reduced pain scores at endpoint compared with placebo when patients of all pain levels were combined (all doses; p < 0.05). In the moderate and severe pain cohorts, pregabalin treatment (300, 600mg/day or flexible) significantly reduced mean pain scores at endpoint compared with placebo (p < 0.01). Pain reduction was greatest in patients with severe baseline pain compared with moderate baseline pain (pregabalin 300, 600mg/day or flexible; p < 0.0001). Pregabalin improved PRSI and PGIC in the moderate and severe cohorts compared with placebo. The greatest improvement in PRSI also occurred in the severe cohort. Treatment-emergent AEs, most commonly dizziness, somnolence and peripheral edema, occurred more frequently in patients treated with pregabalin compared with placebo. Conclusions Pregabalin was effective in pDPN patients with both moderate and severe baseline pain. Patients with severe pain exhibited greater improvements in pain and PRSI than patients with moderate pain. Pain severity may, in part, predict therapeutic response to pregabalin..