Abstract:
BACKGROUND: Opioids and benzodiazepines are central nervous system (CNS) depressants with sedating effects that can adversely impact cognitive as well as motor performance thereby potentially increasing the risk of occupational injury. To date, few studies have assessed the relationships between acute and chronic opioid or benzodiazepine use and occupational injury risk across multiple occupations. METHODS: The primary objective of this study was to examine the risk of occupational injury associated with acute (60 or fewer prescription days supplied in the 180 days preceding injury) opioid or benzodiazepine use across various occupations and in safety sensitive fields. The secondary aim was to determine whether dose escalation (a dose increase of greater than 10%) among workers who chronically use opioids or benzodiazepines was associated with an increased risk of occupational injury. A case crossover study design, employing injury data from the Washington State Department of Labor and Industries workers' compensation claims database paired with the Washington State Prescription Monitoring Program database, was used to examine the study hypotheses. Each hazard period was matched to four control periods. Statistical analyses were performed for 7-day, 14-day, and 28-day hazard and control periods. Conditional logistic regression was used to calculate odds ratios. RESULTS: For acute opioid users, there was a statistically significant decreased risk of occupational injury for 7-day, 14-day and 28-day hazard and control period analyses (OR 0.84, 95%CI 0.80 – 0.89; OR 0.87, 95%CI 0.82 – 0.89; and OR 0.83, 95%CI 0.80 – 0.86 respectively). Similar results were obtained when the analyses were restricted to claims among workers in safety sensitive fields. There was no statistically significant association between acute benzodiazepine use and occupational injury risk even among claimants in safety sensitive fields. Among chronic opioid or benzodiazepine users, increase in opioid or benzodiazepine dose was not associated with an increase in occupational injury risk. CONCLUSION: Acute opioid use was associated with a decreased risk of occupational injury, which was unexpected. This association was similar among claimants in safety sensitive occupations compared to claimants in all occupations. Acute benzodiazepine use was not associated with a statistically significant change in occupational injury risk. Among chronic opioid and benzodiazepine users, increase in medication dose was not associated with a statistically significant change in occupational injury risk. Possible explanations for these findings are explored. These results should be interpreted with caution particularly given potential biases and confounding introduced because of unidirectional control period selection, and opioid prescribing time trends. URI http://hdl.handle.net/1773/40100