Evaluation of Pain Threshold and Tolerance in Diabetics: Influence of Polyneuropathy and Age-Related Changes

Abstract

Diabetes mellitus (DM) is an escalating global health issue, especially in developing countries. The disease is linked to various  complications, with peripheral neuropathy being particularly noteworthy. While early detection is important, the lack of simple, bedside  screening tool in the clinics may deter early detection and prompt management. The aim was to assess the changes in pain threshold  and tolerance among diabetic patients with or without polyneuropathy and healthy controls and the factors associated with it. It is a  cross-sectional comparative study involving 60 diabetic patients (28 with polyneuropathy (PNP), 32 without polyneuropathy (WPNP)),  aged 20-85 years, and 40 apparently healthy controls. Pain threshold and tolerance in the feet, and polyneuropathy were assessed using  the Cold Pressor Test (CPT) and Michigan Neuropathy Screening Index (MNSI) respectively. Results indicate that the majority of  participants were not formally educated (54%), and the age group 40-49 had the highest representation (36%). Most participants were  married (95%) and belonged to the Hausa/Fulani tribe (82%). The majority had been living with diabetes for around 5 years, and most  had Type II DM (90%). Both pain threshold and tolerance of diabetic patients were significantly higher than those of healthy controls, and  diabetic patients with PNP had a significantly higher pain threshold compared to those WPNP. Only the right foot pain threshold and  tolerance of the DM patients WPNP and the left foot of DM patients with PNP were significantly different among different age groups. Significant differences in pain threshold and tolerance between different Duration of Diabetes (DOD) were observed only in PNP patients.  Surprisingly, pain threshold and tolerance of the right foot was always higher than the left foot in DM patients with PNP. Values  of pain threshold and tolerances in both feet increased steadily with advancing age and also longer DOD in patients with PNP. Significant positive correlations between pain threshold and tolerance and the DOD were observed in both feet of the DM patients with PNP.  Significant positive correlations were found between left foot pain threshold, tolerance, and MNSI scores in PNP patients, whereas  insignificant negative correlations were observed in those WPNP. In conclusion, pain threshold and tolerance were significantly higher among PNP compared to WPNP. Pain threshold and tolerance was significantly positively correlated with Age, DOD, and MNSI scores in  DM patients with PNP.