Patients' Global Impression of Change in the management of peripheral neuropathic pain: Clinical relevance and correlations in daily practice

Background Patient-Reported Outcome (PRO) instruments have been developed to evaluate pain management in daily practice; the Patients' Global Impression of Change (PGIC) is particularly recommended by the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials. The prospective non-interventional multicenter PRO-QURE study aimed at assessing correlations between PGIC and pain measurements and treatment effects in patients followed in French pain centres. Methods Respectively, 495 and 379 patients with peripheral neuropathic pain initiating treatment with capsaicin 8% cutaneous patch(es) (female, 62.6%; mean age, 54.0 +/- 14.8 years; post-surgical or traumatic pain, 52.7%; mean pain duration, 42.2 +/- 54.1 months; DN4 score >4, 92.9%) completed the PGIC and several other PRO instruments before (baseline) and 3 months (M3) after treatment application. Results At M3, improvement ("much improved" or "very much improved") was observed in 23.0% of patients, associated with decreases of -3.0 +/- 2.2, -2.5 +/- 2.4, and -23.1 +/- 19.7 in BPI pain intensity, BPI pain interference and NPSI total scores, respectively. The highest Spearman's rank correlation coefficients with PGIC were found for pain intensity (BPI: r = -0.479, p < 0.001), satisfaction with current state (Patient Acceptable Symptomatic State: r = 0.455, p < 0.001), and treatment effectiveness (TSQM: r = 0.431, p < 0.001); correlation coefficients were lower for all NPSI scores, BPI pain interference score, HAD scores and EQ-5D-3L index. Conclusions In daily clinical practice, significant improvement in peripheral neuropathic pain, as assessed by PGIC scores, significantly correlated with changes in well-established measures of pain intensity, pain interference with activities of daily living, mood and quality of life, confirming its clinical interest as PRO measure in real-world conditions. Significance Clinically important improvement in peripheral neuropathic pain, as assessed by PGIC scores, significantly correlated with well-established measures of pain intensity, pain interference in daily life and treatment efficacy. This result, associated with the ease of administration and scoring, encourages the widespread use of the PGIC in daily practice.