Pain and sensory phenotypes of painful diabetic polyneuropathy

Aims: Painful diabetic peripheral neuropathy (pDPN) is a devious condition resulting in reduced overall Quality of life (QoL). The modified Douleur Neuropathique en 4 Questions (DN4)-interview is a seven-item screening tool for neuropathic pain consisting of three pain descriptors and four sensory descriptors. The aim of the present study was to assess the prevalence of neuropathic pain and the different sensory phenotypes in a group of people with diabetes and painful DPN and to perform an exploratory analysis of the correlation between the different pain phenotypes and QoL.

Methods: 6,962 participants with diabetes participated in this observational, cross-sectional survey study. Of these, only participants with a Michigan Neuropathy Screening Instrument questionnaire (MNSIq) score ≥ 4 and DN4-interview score ≥ 3 were included in the analyses (n = 1,085). The prevalence of sensory phenotypes was calculated as the proportion with a given pain descriptor or sensory descriptor out of the total group of participants with painful DPN (MNSIq ≥ 4 and DN4-interview ≥ 3). Pearson’s correlation analysis was performed to evaluate the correlation between pain/sensory descriptors and QoL. Here, sub-scores of The Short Form Health Survey SF(36) were analysed individually, and a z-score was created by summing all sub-scores.

Results: The most prevalent pain descriptors in participants with pDPN were burning pain (73%), electric pain (43%) and cold pain (31%). Pins and needles were experienced in relation to pain in 93% of the participants, tingling in 82%, and numbness in 55%, while 44% experienced itching. Weak correlations with QoL were found for cold pain (r -0.122 to -0.176), electric pain (r -0.116 to -0.140), numbness (r -0.109 to -0.164), and itch (r -0.103 to -0.177).

Conclusions: The present study reveals differences between the seven DN4 pain phenotypes in terms of impact on the risk of depression, anxiety and reduced overall QoL. An increased focus on differences in pain phenotypes is of utmost importance to move the field forward towards more personalized, mechanism-based, treatment-regimes.