Inter-trial Variation in the Sensitivity of Thermal Threshold Testing for the Diagnosis of Neuropathy in Type 2 Diabetes Mellitus

• Published in: International journal of applied and basic medical research Vol. 14; no. 3; pp. 182 - 186
• Main Authors: Gaur, Archana, Varatharajan, Sakthivadivel, Taranikanti, Madhuri, John, Nitin Ashok, Kalpana, Medala, Ganji, Vidya, Umesh, Madhusudhan, Katta, Roja
• Format: Journal Article
• Language: English
• Published: India Medknow Publications & Media Pvt. Ltd 01-07-2024; Wolters Kluwer - Medknow
• Subjects: Diabetes; Diabetic neuropathy; Original; Diabetic neuropathy; sensitivity; validity; temperature threshold testing; trials
• ISSN: 2229-516X; 2248-9606
• DOI: 10.4103/ijabmr.ijabmr_207_24

Thermal threshold testing (TTT) is a simple non-invasive approach for diagnosing diabetic neuropathy earlier. Conventionally the TTT is done in all four limbs and at least 6 trials are done to obtain the mean threshold, which is time consuming.
We propose to assess the validity and reliability of reduced number of trials of TTT in the lower limbs.
After obtaining ethics approval from the Institute Ethics Committee, 100 patients with type 2 Diabetes Mellitus of both gender between the ages of 35 to 65 years attending medicine OPD were recruited. Neuropathy assessment was done using Temperature threshold testing. At least 6 trials were performed for each site and the mean threshold obtained. The mean of 5 trials, 4 trials and 3 trials were noted for the comparison.
On comparing hot tests of 3 trials with 6 trials had a sensitivity and specificity of 88.7% and 96.6 %. In cold threshold testing, 4 trials and 3 trials showed similar results of sensitivity of 77.8%, specificity of 98.8%. The measures of agreement between the hot trials 6 vs 5 had Kappa value of 0.953, 6vs 4 showed a Kappa value of 0.862 and 6 vs 3 showed Kappa value of 0.819.
Hot threshold tests of lower limb are more sensitive than cold thresholds. The 4 trial test is a reliable test and can be performed over 6 trial tests. When time is a factor, three trials are sufficient to diagnose small fibre neuropathy.