Statin Treatment is Associated with a Lower Risk of Carpal Tunnel Syndrome, but Not of Ulnar Nerve Entrapment, in Type 2 Diabetes – A Nationwide Register Study

Department of Translational Medicine - Hand Surgery, Lund University, Malmö, Sweden

R. Perez, J. Merlo, P. M. Nilsson, A. Gottsäter, M. Zimmerman 

Individuals with diabetes have a risk for nerve entrapment disorders like carpal tunnel syndrome (CTS) and ulnar nerve entrapment (UNE). They are often treated with statins, which have potential side effects, such as peripheral neuropathy. We investigated whether statin treatment affects the risk of CTS and UNE in type 2 diabetes (T2D). Data from multiple combined Swedish national registers using unique personal identification numbers identified individuals with a first diagnosis of CTS or UNE 2011-2014, irrespective of surgery. Individuals diagnosed with T2D within five years before CTS or UNE diagnosis were included in the diabetes group. Statin treatment was defined as a prescription of statins within five years before baseline. Multinomial regression analysis was used to assess Relative Risk (RR [95% confidence interval; CI]) of CTS and UNE with statin treatment (reference: general population). In total, 5,100,516 individuals (CTS: 46,545; UNE: 8,253; T2D: 292,252; statin-treated: 155,001) were included. When stratifying for diabetes [adjusted for age, sex, statin indication (i.e., cardiovascular diseases), complications (i.e., nephropathy and retinopathy), and socioeconomic factors], the risk of CTS (1.2 [1.1-1.2]) was higher in individuals without diabetes but with statin treatment. In individuals with diabetes, statin treatment lowered the risk of CTS (0.8 [0.7-0.9]). No associations with statin treatment and UNE were seen in individuals without or with T2D (1.0 [0.9-1.2]; 1.0 [0.7-1.2], respectively). Statin indication increased risks for CTS and UNE in individuals without T2D and UNE in T2D. The presence of nephropathy or retinopathy increased the risk for CTS, but not for UNE, in individuals with T2D. Statin treatment is associated with a higher risk of CTS in individuals without diabetes and a lower risk in individuals with T2D but does not affect the risk of UNE. Complications of T2D, indicating long duration, increased the risk for CTS but not UNE.