Reliability of Gait Analysis Using ORPHE ANALYTICS in Patients with Type 2 Diabetes: A Single-center Observational Study.

Introduction: People with diabetes tend to show abnormalities in gait parameters, including walking speed and stride length, relative to those without diabetes. While inertial measurement units (IMUs) provide a portable alternative to optical motion capture systems, the reliability of gait analysis is influenced by factors such as walking distance, timing, and examiner differences. However, the impact of these parameters on gait analysis in patients with type 2 diabetes (T2D) remains unclear. This study aimed to evaluate the reliability of ORPHE ANALYTICS, an IMU-based gait analysis system, under varying measurement conditions in patients with T2D.

Methods: We conducted a single-center observational study (n = 9) to clarify the reliability of ORPHE ANALYTICS, a gait analysis motion sensor system developed by ORPHE Inc., which evaluates more than 15 gait parameters, in patients with T2D. The relative reliability was assessed using intraclass correlation coefficients (ICC): ICC_(1,1) or ICC_(1,3) for intra-rater reliability and ICC_(2,1) for inter-rater reliability based on the differences in distance (10 vs. 30 m), examiners, and timing (morning vs. afternoon).

Results: Intra-rater reliability was excellent (ICC_(1,1) and ICC_(1,3) ≥0.9) for all gait parameters except coefficient of variation of stride duration and lateral displacement. Measurements taken under different conditions of distance and timing exhibited almost good inter-rater reliability (ICC_(2,1) ≥0.75), while measurements by different examiners exhibited moderate to good reliability (ICC_(2,1) ≥0.50). Significant novel differences were observed in lateral sway during the swing phase, medial sway during the stance phase, and foot angle, with random errors (expressed as percentage of minimal detectable change) exceeding 40% under various measurement conditions.

Conclusions: ORPHE ANALYTICS exhibited good to excellent intra-rater and inter-rater reliability based on differences in distance and timing. However, persistent inter-rater reliability challenges in patients with T2D warrant analysis by a single examiner.