It is suggested that there are several distinct pain sensory profiles across various neuropathic pain disorders that may reflect distinct pathophysiological mechanisms.
This manuscript aimed to characterize the clinical profile of various neuropathic pain (NeP) disorders and to identify whether patterns of sensory symptoms/signs exist, based on baseline responses on the Neuropathic Pain Symptom Inventory (NPSI
) questionnaire and the quantitative sensory testing (QST
). These post hoc analyses were based on data from 4 randomized, double-blind, placebo-controlled clinical studies of pregabalin (150–600 mg/day) in patients with NeP syndromes: central poststroke pain, posttraumatic peripheral pain, painful HIV neuropathy, and painful diabetic peripheral neuropathy. The NPSI
questionnaire includes 10 different pain symptom descriptors. QST
was used to detect sensory thresholds of accurately calibrated sensory stimuli and to quantify the intensity of evoked sensation. To identify symptoms/signs clusters and select the number of clusters, a principal component analysis (PCA) and hierarchical clustering methods with clinical input were used. Analysis of the NPSI
pain qualities and individual QST
measures at baseline indicated no clear association between particular symptoms/signs profiles and etiologies. Based on NPSI
symptoms, PCA identified 3 pain dimensions: provoked, deep, and pinpoint. A hierarchical cluster analysis
identified 3 clusters with distinct pain characteristics profiles independent of NeP syndrome. Based on QST
signs, PCA identified 2 pain dimensions: evoked by cold and evoked by touch. A hierarchical cluster analysis
identified 4 clusters with distinct pain characteristics profiles. These “trans-etiological” profiles may reflect distinct pathophysiological mechanisms and therefore, potential differential responses to treatment.