Effectiveness of Pregabalin Treatment for Neuropathic Pain in Patients with Spine Diseases: A Pooled Analysis of Two Multicenter Observational Studies in Japan

Abstract

Purpose: Neuropathic pain (NeP) is common among patients with chronic pain associated with spine diseases. Practical effectiveness of pregabalin, one of the first-line treatments for NeP, has not been evaluated in an entire population of patients with spine diseases, including various pathophysiological conditions. This pooled analysis aimed to evaluate the therapeutic value of pregabalin for chronic pain with NeP component in patients with spine diseases in routine primary care settings.

Patients and methods: We pooled data from two 8-week prospective observational cohort studies for patients with chronic low back pain with accompanying lower limb pain (NeP component), and patients with chronic cervical pain and accompanying upper limb radiating pain (NeP component) in routine primary care settings in Japan. For both studies, patients were treated for 8 weeks with pregabalin (alone/with other analgesics) or usual care with conventional analgesics (eg, non-steroidal anti-inflammatory drugs). Changes in pain numerical rating scale (NRS), Pain-Related Sleep Interference Scale (PRSIS), and EuroQol 5-dimension 5-level (EQ-5D-5L) scores from baseline to week 8 were summarized and compared between the pregabalin and usual care groups, and also for subgroups of primary diagnosis. Safety was evaluated by adverse events (AEs) in the pregabalin group.

Results: The pooled dataset comprised 700 patients (pregabalin group: 302; usual care group: 398). All patient-reported outcomes (PRO) scores significantly improved from baseline to week 8 in the pregabalin than in the usual care group (NRS: P<0.0001; PRSIS: P<0.0001, and EQ-5D-5L: P=0.0006). Overall, all three PRO measures showed greater improvement in the pregabalin than in the usual care group, irrespective of the primary diagnosis. AEs were reported in 36.1% of the pregabalin group.

Conclusion: This analysis suggested multi-faceted effectiveness of treatment with pregabalin from the patient's perspectives under a "real-world" practice in all patients with chronic NeP from various spine diseases.

Keywords: chronic pain; neuropathic pain; pooled analysis; pregabalin; spine diseases.

Figure 1

Least-squares mean change in NRS scores (A), PRSIS scores (B), and EQ-5D-5L scores (C) from baseline at week 4 and week 8. Notes: Data from the FAS are presented. LS mean (95% CI) treatment difference (pregabalin vs usual care) in (A) ^aWeek 4: -0.73 (-1.00, -0.46); ^bWeek 8: -1.06 (-1.36, -0.76), (B) ^aWeek 4: -0.69 (-1.00, -0.39); ^bWeek 8: -0.90 (-1.21, -0.60), (C) ^aWeek 4: 0.04 (0.02, 0.06); ^bWeek 8: 0.03 (0.01, 0.05). Abbreviations: CI, confidence interval; EQ-5D-5L, EuroQol 5-dimension 5-level; FAS, full analysis set; LS, least-squares; NRS, numerical rating scale; PRSIS, Pain-Related Sleep Interference Scale.

Figure 2

Shift in the pain intensity level from baseline to week 8 by intensity level at baseline (A) moderate and (B) severe. Note: Pain intensity level was based on NRS: mild (0–3), moderate (4–6), and severe (7–10). Patients included were those with available NRS data at Week 8. Abbreviation: NRS, numerical rating scale.

Figure 3

Change in NRS scores (A), PRSIS scores (B), and EQ-5D-5L scores (C) from baseline by primary diagnosis at week 8. Notes: Data from the FAS are presented. The number of patients diagnosed with compression fracture due to osteoporosis or cervical spondylosis was too small to estimate the treatment effects in the model, and thus these subgroups were not included in this analysis. Abbreviations: CI, confidence interval; EQ-5D-5L, EuroQol 5-dimension 5-level; FAS, full analysis set; LS, least-squares; NRS, numerical rating scale; PRSIS, Pain-Related Sleep Interference Scale.