Background/Purpose: Flavocoxid is a medical food formulated to assist in the management of patients with osteoarthritis (OA). Safety concerns based on case reports have been raised related to an association with acute liver injury and hypersensitivity pneumonitis (HP). However, the absolute and comparative risk of these events relative to NSAIDs is unclear. Our objectives were to determine the incidence rate (IR) of severe acute liver injury, HP and other outcomes in a cohort of OA patients who were new users of flavocoxid versus prescription NSAIDs

Methods: MarketScan claims data (2006-2016) was used to identify patients age >=50 initiating flavocoxid or prescription NSAIDs with a history of OA or back pain and >= 6 months coverage before initiation. Patients were excluded if they had prior events or malignancy. New users defined by 6-month baseline period of non-use prior to initiation. Exposure was defined by days of supply + a 30 day extension, with a sensitivity analysis conducted with a 90 day extension.

Primary outcomes included hospitalization for HP and drug-induced liver injury, based on ICD-9 codes. Secondary outcomes included hospitalized GI bleed and acute myocardial infarction (MI). Poisson regression was used to calculate crude incidence rates per 1000 person-years (PY) and 95% confidence intervals (CI). Propensity scores (PS) were used to match (1:2) flavocoxid to NSAID users based on demographics and >200 comorbidities (based on AHRQ’s CCS groupings). Cox regression was used for calculating adjusted hazard ratios (aHR).

Results: A total of 4800 flavocoxid and 2,129,727 NSAID new users met eligibility criteria. Prior to PS matching, many imbalances between flavocoxid and NSAID users were observed, all of which were greatly attenuated after PS matching. Post-match mean age for flavocoxid was 57, NSAIDs was 57. Flavocoxid users had higher prevalence of comorbidities and more healthcare utilization. The IR for HP associated with flavocoxid was 1.0 (95%CI 0.3-3.2) and for hospitalized liver injury was 4.1/1000, which after adjustment, was significantly elevated (aHR for HP: 5.6, 95%CI 0.5–68.6; aHR for hospitalized liver injury: 3.9, 95%CI 1.4-10.8 referent to NSAID use). Rates and aHR for GI bleed were lower (aHR=0.5, 95%CI 0.3-0.9) and there were no significant differences for MI.

Conclusion: The absolute risk for HP and severe liver injury associated with flavocoxid is low (1-4/1000py) but higher than in NSAID users, with a rate difference ~2/1000py). The risk-benefit profile of flavocoxid needs to be considered in light of its efficacy and overall safety profile including lower rates of hospitalized GI bleeding

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/comparative-safety-of-flavocoxid-limbrel-versus-nsaids-among-osteoarthritis-patients/