Diabetic polyneuropathy and carpal tunnel syndrome together affect hand strength, tactile sensation and dexterity in diabetes patients

AIMS/INTRODUCTION: Carpal tunnel syndrome (CTS) and diabetic polyneuropathy (DPN) can occur together, and this concomitance is thought to be higher in diabetes patients. We aimed to examine and compare hand function in type 2 diabetes mellitus patients without CTS and DPN (CTS−DPN−), patients with CTS without DPN (CTS+DPN−), patients with DPN without CTS (CTS−DPN+), and patients with CTS and DPN (CTS+DPN+). MATERIALS AND METHODS: A total of 161 type 2 diabetes mellitus patients underwent physical examination and electrodiagnostic tests. Grip and pinch strengths, tactile sensory thresholds were measured for each participant. Purdue pegboard test was used in evaluating the hand dexterity of the participants. RESULTS: Of the 161 type 2 diabetes mellitus participants, 36 (22.4%) had both CTS and DPN. CTS participants had lower grip (26.6 ± 10.6 vs 35.2 ± 14.3, P < 0.001) and pinch (6.3 ± 2.6 vs 7.5 ± 2.9, P = 0.026) strengths compared with non‐CTS participants, whereas DPN participants had elevated tactile sensory thresholds of both the second (2.8 [2.8–3.6] vs 2.4 [2.4–2.8], P < 0.001) and the fifth (2.8 [2.8–3.6] vs 2.4 [2.4–2.8], P < 0.001) fingers compared with non‐DPN participants. The CTS+DPN+ group had lower Purdue pegboard test scores than other groups. Grip (r = 0.482, 0.530, 0.467, 0.498, all P < 0.001) and pinch (r = 0.246, P = 0.003; r = 0.265, P = 0.001; r = 0.264, P = 0.001; r = 0.235, P = 0.005) strengths were positively correlated with Purdue pegboard test scores, whereas tactile sensory thresholds were negatively correlated with Purdue pegboard test scores (r = −0.447 to −0.359, all P < 0.001). CONCLUSION: Type 2 diabetes mellitus patients with both DPN and CTS had lower grip and pinch strengths and decreased tactile sensation, both of which were correlated with poorer hand dexterity.