Predictors of Carpal Tunnel Syndrome Severity Using the GEHS Classification System in a Hawaiʻi Patient Population

Introduction: Carpal tunnel syndrome (CTS) is the most common compressive neuropathy of the upper extremity and occurs when the median nerve is compressed as it passes through the carpal tunnel at the wrist. Patients commonly experience numbness, tingling, pain, and weakness of the hand, with symptoms that may progressively worsen if left untreated. Although a thorough clinical history and physical examination can suggest CTS, electrodiagnostic testing with nerve conduction studies (NCS) and electromyography (EMG) remains an important objective method for confirming median neuropathy and assessing its severity. Several classification systems have been developed to grade CTS severity; however, differences in the electrophysiological criteria used can lead to variability in severity classification. The Greenhouse, Ernst, Halle, and Shaffer (GEHS) classification system categorizes CTS severity using objective electrodiagnostic findings, including NCS and EMG parameters. The purpose of this study was to evaluate demographic, clinical, and electrophysiological characteristics across GEHS severity groups and identify factors associated with greater CTS severity in a Hawaiʻi patient population.

Methods: This retrospective, single-center chart review included adults ≥ 18 years of age diagnosed with CTS between January 2013 and February 2026 with electrodiagnostically confirmed CTS on nerve conduction studies (NCS) and electromyography (EMG). Eligible patients were identified using ICD-10 diagnostic codes G56.0, G56.01, G56.02, and G56.03. Demographic and clinical data collected from electronic health records included age, sex, insurance status, BMI, CTS laterality, and relevant comorbidities, such as obesity, diabetes mellitus, and hypothyroidism. Patient-reported symptoms were also recorded, including numbness, pain, tingling, nocturnal symptoms, and weakness. Electrodiagnostic variables were collected from corresponding EMG reports and included median distal motor latency and amplitude to abductor pollicis brevis, median digit 2 sensory distal latency, and median palm-wrist sensory latency. CTS severity was assigned to each patient according to the Greathouse, Ernst, Halle, and Shaffer (GEHS) classification system. Patient characteristics were summarized descriptively, and ordered logistic regression was performed to identify demographic and comorbidity factors associated with greater CTS severity.

Results: A total of 278 individuals were included in the analysis, of whom 59% were female and 41% were male. Based on the Greenhouse Electrodiagnostic Severity (GEHS) classification, 59.0% of patients had mild, 19.4% moderate, and 21.6% severe CTS. On univariate analysis, increasing CTS severity was associated with older age (p<0.001), diabetes (p<0.001), chronic kidney disease (p=0.026), and lower distal motor amplitude (p<0.001). In multivariable ordinal logistic regression, increasing age remained an independent predictor of greater CTS severity, with each additional year associated with a 4% increase in the odds of a higher GEHS stage (OR 1.04, 95% CI 1.02–1.06; p<0.001). Diabetes was also independently associated with greater CTS severity (OR 2.18, 95% CI 1.17–4.06; p=0.014), whereas obesity, hypertension, hyperlipidemia, and sex were not significant predictors.

Conclusion: The Greathouse, Ernst, Halle, and Shaffer (GEHS) classification provides a standardized method for grading CTS severity using electrodiagnostic findings. In this study, older age and diabetes mellitus were independently associated with more severe CTS, whereas obesity, hypertension, hyperlipidemia, and sex were not. These findings support the use of electrodiagnostic severity classification to objectively characterize disease severity and identify patients at risk for more advanced CTS. A standardized grading system may improve consistency in severity assessment, facilitate communication between providers, and help guide treatment decisions. Future studies should evaluate whether GEHS severity is associated with patient symptoms, functional impairment, and treatment outcomes across diverse patient populations.