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Opioids Top the Drug List in California Workers' Comp Polypharmacy Claims

Oakland, CA - Efforts to curb opioid use in California workers’ compensation have been successful, but new research by the California Workers’ Compensation Institute (CWCI) shows they remain very common among claims in which injured workers are given multiple concurrent prescriptions, and are the most prevalent type of drug found in polypharmacy claims that involve five or more concurrent prescriptions.

Polypharmacy is the simultaneous use of multiple drugs by a patient to treat one or more medical conditions.  Ancillary medications are often used to mitigate the risks and side effects of other drugs prescribed to a patient, but combining drugs can present other health risks, including potentially dangerous drug interactions and the risks of overdosing.  The risks are particularly high when opioids or other controlled substances are part of the drug mix, underscoring the importance of utilization review and other forms of clinical oversight.  Because of these risks, polypharmacy has generated concern across healthcare systems, including worker’s compensation.  To see how prevalent it is in California workers’ compensation, and to identify the characteristics of polypharmacy claims, CWCI used its Industry Research Information System (IRIS) database to generate a sample of claims in which prescriptions were dispensed to California injured workers in 2016 and 2017.  For purposes of the study, claims with five or more concurrent medications during the two-year study period were defined as polypharmacy claims, while for comparative purposes the analysts also examined data on claims with fewer than five concurrent prescriptions. 

Overall, 43 percent of the claims in the study sample had no overlapping prescriptions; 33 percent had two concurrent prescriptions; 20 percent had three to four concurrent prescriptions; while 4 percent had five or more concurrent prescriptions and were considered polypharmacy claims.  Among other findings from the study: 

• The likelihood that indemnity was paid on a claim increased with the number of prescriptions. Just over half (51.6 percent) of the claims with one to two prescription drugs involved indemnity payments, but that percentage rose to 91.3 percent for claims with five or more concurrent drugs.
• Polypharmacy claims tended to be older: 21.5 percent of the claims with five or more concurrent prescriptions were at least 10 years old compared to 6.0 percent of the non-polypharmacy claims.
• Polypharmacy is more common among older workers. More than half (52.3 percent) of the polypharmacy claims involved injured workers who were 50 years of age or older at the time the drugs were dispensed, versus 38.3 percent of those who received fewer concurrent prescriptions.
• The top diagnostic category for polypharmacy claims, noted in 21.3 percent of the cases, was back conditions without spinal cord involvement, which includes back sprains and strains, one of the most common work-related injuries. Other common diagnoses included ruptured tendons, tendonitis, myositis and bursitis (10.2 percent of the polypharmacy claims); shoulder, arm, knee, and lower leg sprains (9.5 percent); and other heart and circulatory disorders (9.1 percent).    
• Opioids and anti-inflammatories were the most common drugs found in claims with three or more concurrent prescriptions. Opioids, anti-inflammatories and muscle relaxants were the top three-drug combination, while the same three drug groups along with gastrointestinal agents were the top four-drug combination.
• Among claims with three or more concurrent prescriptions, opioids were present in 13 of the top 20 drug combinations; while among claims with four or more concurrent prescriptions, opioids were present in 16 of the top 20 drug combinations.
• Opioids were the most common type of drug dispensed in claims with five or more concurrent prescriptions, noted in one out of every six of these polypharmacy claims. Anti-inflammatories were the number two drug category in the polypharmacy claims, present in one out of every seven of these claims, followed by gastrointestinal agents, muscle relaxants, and antidepressants.

CWCI has issued its polypharmacy study in a Research Note, “An Examination of Polypharmacy Claims in California Workers’ Compensation,” which has additional data, graphics and analyses.  The free report is available in the Research section of the Institute’s website, www.cwci.org.