Effectiveness of pregabalin for the treatment of chronic low back pain with accompanying lower limb pain (neuropathic component): a non-interventional study in Japan

Abstract

Objective: To evaluate the impact of pregabalin on sleep, pain, function, and health status in patients with chronic low back pain with accompanying neuropathic pain (CLBP-NeP) under routine clinical practice.

Methods: This prospective, non-interventional, observational study enrolled Japanese adults (≥18 years) with CLBP-NeP of duration ≥3 months and severity ≥5 on a numerical rating scale (0= no pain, 10= worst possible pain). Treatment was 8 weeks with pregabalin (n=157) or usual care alone (n=174); choice of treatment was determined by the physician. The primary efficacy outcome was change from baseline to 8 weeks in pain-related interference with sleep, assessed using the Pain-Related Sleep Interference Scale (PRSIS; 0= did not interfere with sleep, 10= completely interferes with sleep). Secondary endpoints were changes in PRSIS at week 4, and changes at weeks 4 and 8 in pain (numerical rating scale), function (Roland-Morris Disability Questionnaire), and quality of life (EuroQol 5D-5L); global assessments of change were evaluated from the clinician and patient perspectives at the final visit.

Results: Demographic characteristics were similar between cohorts, but clinical characteristics suggested greater disease severity in the pregabalin group including a higher mean (standard deviation) pain score, 6.3 (1.2) versus 5.8 (1.1) (P<0.001). For the primary endpoint, pregabalin resulted in significantly greater improvements in PRSIS at week 8, least-squares mean changes of -1.3 versus -0.4 for usual care (P<0.001); pregabalin also resulted in greater PRSIS improvement at week 4 (P=0.012). Relative to usual care at week 8, pregabalin improved pain and function (both P<0.001), and showed global improvements since beginning study medication (P<0.001). Pregabalin was well tolerated.

Conclusion: In clinical practice in patients with CLBP-NeP, pregabalin showed significantly greater improvements in pain-related interference with sleep relative to usual care. In addition, pregabalin significantly improved pain, function, and health status, suggesting the benefits of pregabalin for overall health and well-being relative to usual care in these patients. (Clinicaltrials. gov identifier NCT02273908).

Keywords: chronic low back pain; neuropathic pain; non-interventional study; pregabalin; sleep; usual care.

Figure 1

Patient disposition. Notes: ^*Choice of therapy determined by the clinical judgment of the treating physician; ^#the full analysis set consisted of subjects who had at least one evaluable observation from any of the patient-reported outcomes, and only evaluable subjects who contributed to the particular outcome were evaluated in each analysis.

Figure 2

Change from baseline in sleep disturbance, assessed using the Pain-Related sleep interference scale (PRSIS). Note: ^*P<0.05 versus usual care. Abbreviation: LS, least-squares.

Figure 3

Efficacy of treatment for pain assessed using a pain numerical rating scale (NRS). Notes: (A) Change from baseline. (B) Proportions of patients at week 8 (last observation carried forward) reporting clinically relevant improvements in pain. ^*P<0.05 versus usual care. Abbreviation: LS, least-squares.

Figure 4

Change from baseline in function, assessed by the Roland-Morris Disability Questionnaire (RMDQ). Note: ^*P<0.05 versus usual care. Abbreviation: LS, least-squares.

Figure 5

Global impression of change at week 8 from the perspectives of (A) the clinician, assessed using the Clinician Global Impression of Change (CGI-C), and (B) the patient, assessed using the Patient Global Impression of Change (PGI-C). Notes: Categories are collapsed into “Improved”, consisting of “minimally improved”, “much improved”, and “very much improved”, and “Worsened”, consisting of “minimally worse”, “much worse”, and “very much worse”. Differences between pregabalin and usual care were significant for the full set of categories on the CGI-C and PGI-C (both P<0.05).