Reliability of Digital Pressure Algometer in Painful Diabetic Peripheral Neuropathy: A Quantitative Cross-sectional Study

Abstract

Introduction: Painful Diabetic Peripheral Neuropathy (PDPN) is associated with pain and disturbed sensory symptoms. Altered Pressure Pain Threshold (PPT) in PDPN often leads to complications of diabetic foot and consequent amputations. Early detection of altered PPT can prevent future complications and reduce mortality rates. PPT may be determined with a pressure algometer, which measures the pressure and/or force at which the first perception of pain begins. The cost of algometers frequently prevents them from being used in clinical and research settings. An affordable and dependable algometer would be a valuable tool in PDPN, where health costs are already 20% higher than those of diabetic controls. Aim: To evaluate the test-retest and inter-rater reliability of a low-cost digital pressure algometer in individuals suffering from PDPN. Materials and Methods: This quantitative cross-sectional study was conducted for four months at Metro Heart Institute with Multispeciality Hospital, Faridabad, Haryana, India. PPT of 30 patients with PDPN aged 50-70 years (mean age 61.53±5.84 years) was collected twice by one rater (R1) after a gap of 24 hours. Another rater (R2) repeated the first reading at similar points on both feet. PPT was noted at the dorsum, 2nd, and 3rd metatarsal on the plantar surface of the foot. The main outcome measurements were the Intraclass Correlation Coefficient (ICC), Standard Error of Measurement (SEM), Minimal Detectable Change (MDC), and using the Bland-Altman approach, measurement bias was evaluated. Results: The ICC for test-retest reliability for the dorsal right and left foot was 0.85 and 0.83, respectively. The ICC for Plantar 2nd metatarsal right and left was 0.86 and 0.89, respectively. The ICC for the plantar third metatarsal right and left foot was 0.85 and 0.81, respectively. The inter-rater reliability ICC values varied from 0.63 to 0.87. Bland-Altman plots showed acceptable levels of agreement. Conclusion: The digital algometer showed good test-retest and moderate inter-rater reliability in patients with PDPN.

Keywords

• inter-rater reliability
• pressure pain threshold
• test-rest reliability