Association Between Diabetes Mellitus and Carpal Tunnel Syndrome: Results From the United States National Ambulatory Medical Care Survey

Background Carpal tunnel syndrome (CTS) is the most common compression neuropathy in the upper limb. While various risk factors have been linked to CTS, the role of diabetes mellitus (DM) in the development of CTS remains unclear. Previous studies have failed to consistently demonstrate a clear association between DM and CTS due to variations based on the geographic setting and differences in the study design. The objective of this study was to assess if there is an association between DM and CTS using population-based data from the United States. Methodology We used data from patients >= 18 years old who contributed to the National Ambulatory Medical Care Survey between 2006 and 2015. The outcome was CTS identified by the International Classification of Diseases-9-Clinical Modification codes (354.0 and 354.1), and the main independent variable was physician-reported diabetes status. Multivariable logistic regression was used to adjust for confounding variables. Odds ratios (ORs) and 95% confidence intervals (CIs) were reported. Stata v15 was used for all analyses. Results Among the patients included in this study (n = 322,092), 13.5% were reported to have diabetes while 0.55% reported CTS. The unadjusted odds of having CTS among patients with diabetes was 0.92 (95% CI: 0.74-1.14; p = 0.447). After adjusting for confounding variables, the association remained not statistically significant (adjusted odds ratio [aOR]: 0.84; 95% CI: 0.65-1.09; p = 0.203). Other variables independently associated with CTS included age 50-59 (aOR: 1.91; 95% CI: 1.49-2.45; p < 0.001), female gender (aOR: 1.31; 95% CI: 1.09-1.58; p < 0.004), and current tobacco users (aOR: 1.32; 95% CI: 1.07-1.63; p < 0.01). Conclusions No association was found between DM and CTS in adult ambulatory patients in the United States, but results should be considered in light of potential outcome misclassification.