Lifetime risk of symptomatic carpal tunnel syndrome in Type 1 diabetes

To determine the lifetime risk of developing symptomatic carpal tunnel syndrome (CTS) in subjects with Type 1 diabetes and to investigate the effect of glycaemic control, body mass index (BMI), gender and age of onset of diabetes.

One hundred and twenty-two consecutive subjects with Type 1 diabetes seen by a single investigator, over 1-year, were questioned about previous surgery for, or current symptoms of CTS. Those with current symptoms were referred for nerve conduction studies (NCS). Those with previous surgery and/or diagnostic NCS were classified as having CTS. Lifetime risk was calculated by the Kaplan-Meier method.

Twenty six out of 122 patients had CTS, 18 of whom (69%) had undergone median nerve decompression surgery. The predicted lifetime risk of CTS reached 85% after 54 years of Type 1 diabetes (95% confidence interval: 72-97%). The duration of diabetes was greater in those who had developed CTS than in those who had not (29 vs. 19 years, P=0.0001). In those diagnosed with diabetes before the age of 20 there was a lag time of at least 19 years before the development of CTS, whereas patients with later onset of diabetes, began to develop CTS from as early as 5 years diabetes duration. There was no demonstrable effect of glycaemic control, obesity, gender or retinopathy on the appearance of CTS.

The lifetime risk of developing symptomatic CTS with Type 1 diabetes is high, and is related to age and duration of diabetes, but not to the development of microvascular complications.