BACKGROUND: Carpal Tunnel Syndrome (CTS) is among the most disabling workplace injuries and illnesses with great economic burden on workers and their communities. Chronic comorbidities are a large contributor to medical expenditures and influence CTS risk, though their impact on workers’ compensation (WC) is not well understood. This study examines the role of chronic comorbidities on CTS WC claimants on return to work and earnings.
METHODS: Washington WC data was used to identify claimants with CTS in 2008 through 2009. Diagnosis codes extracted from WC medical billing data were used to determine chronic disease status using the Health Care Utilization Project criteria. WC data were linked to unemployment insurance data to follow CTS claimants five years after injury to examine effect of chronic disease on hours worked and yearly earnings. Age, sex, Body Mass Index (BMI), industry type, having had CTS or wrist endoscopy surgery, and rural or urban residence were covariates collected. Linear regression modeling was used to examine the effect of chronic comorbidities on hours worked and earnings recovery post injury. Statistically significant covariates (alpha=0.05) were included in the final multivariable linear regression model.
RESULTS: CTS accounts for approximately 3% of all Washington State WC time loss claims, and 11% of total WC time loss claim costs. The majority (56%) of CTS claimants in the cohort (n=1885) were diagnosed with at least one additional chronic comorbidity. Overall, the CTS cohort worked 67%, 60%, and 56% of their pre-injury hours and earned 67%, 60%, and 58% of their pre-injury earnings one-, three-, and five-year post injury, respectively. Compared to CTS claimants with no chronic comorbidities and controlling for sex, industry type, and surgery status, the claimants with chronic comorbidities had relative hours recovery (RHR) and relative earnings recovery (RER) post injury as follows: [RHR: 0.55 (95% confidence interval (CI): 0.42–0.73) and RER: 0.53 (95% CI: 0.40–0.70), one-year post injury]; [RHR: 0.26 (95% CI: 0.17–0.38) and RER: 0.25 (95% CI: 0.17–0.37), one-year post injury]; [RHR: 0.55 (95% CI: 0.42–0.73) and RER: 0.53 (95% CI: 0.40–0.70), three-years post injury]; and [RHR: 0.26 (95% CI: 0.17–0.39) and RER: 0.26 (95% CI: 0.17–0.39), five-years post injury].
CONCLUSIONS: Wage and hours recovery are significantly lower for CTS claimants with chronic comorbidities. These findings indicate that return to work is more difficult for these claimants and addressing these chronic comorbidities could improve job retention and the financial burden of CTS.