Insulin resistance increases risk of carpal tunnel syndrome: a case-control study.

Carpal tunnel syndrome (CTS) is one of the most common upper limb compression neuropathies. In only 50% of cases it is possible to identify a cause. Our objective was to determine the role of glucose metabolism abnormalities in idiopathic CTS. We identified 117 patients with idiopathic moderate or severe CTS and 128 controls. In all we evaluated glucose and insulin levels at fasting and after 2-h oral glucose tolerance test (2h-OGTT). In addition we determined insulin resistance (IR). Following OGTT the prevalence of glucose metabolism abnormalities was significantly higher in the CTS group (p = 0.001). IR was documented in 80% of patients, of whom 45% had impaired glucose tolerance, 14% newly diagnosed diabetes mellitus, and 20% IR only. Waist circumference and body mass index were also significantly increased in the CTS group. In this study, we focused on evidence that pre-diabetes may represent a risk factor for CTS. We proposed to determine IR as a rule in all patients with idiopathic CTS.