Quantitative sensory testing and skin biopsy for neuropathy assessment in Type 1 Diabetes: a comparative study

Abstract

Background: Skin biopsy (SB) is frequently considered the gold standard for detecting neuropathy, a frequent complication of Diabetes Mellitus type I (DM1). However, its invasive nature makes it less accessible for routine screening, highlighting the relevance of using other diagnostic tools. Therefore, this study aims to analyze the diagnostic accuracy of Quantitative Sensory Testing (QST) in detecting neuropathy, taking into account the diagnosis of this condition according to SB. Methods: A cross-sectional study of different subgroups of pain and neuropathy was realized in a sample of 49 DM1 patients and 14 healthy controls. All participants were submitted to QST and SB to evaluate neuropathy. Predictive models using different combinations of QST parameters were estimated through logistic regression. Afterwards, the cut-offs to distinguish neuropathy was defined through Receiver Operating Characteristic (ROC) analysis using the Youden index criterion. Results: Neuropathy defined using SB was present in a great majority of patients with DM1, particularly among those with painful neuropathy (94.7%, p<0.001). Among QST parameters, Cold Detection Threshold (CDT), Warm Detection Threshold (WDT), Mechanical Detection Threshold (MDT), Mechanical Pain Threshold (MPT) and Vibration Detection Threshold (VDT) were associated with the diagnosis of neuropathy using SB. Predictive models using different combinations of these parameters showed ROC curve areas between 0.788 and 0.790, with cut-off values ranging from 0.594 to 0.768 and sensitivity/specificity between 60%-74% and 81%-100%, respectively. Conclusions: Several QST parameters were associated with neuropathy, as defined using SB, particularly CDT, WDT, MPT, VDT and MDT demonstrating good diagnostic accuracy. This non-invasive method may be used for identifying and tracking diabetic neuropathy, ultimately improving patient management and early intervention strategies.