RESUMO
INTRODUCTION: Knee osteoarthritis (OA) is a chronic pathology that is treated across multiple specialties. Opioid prescribing practices for knee OA have not been described on a national level. The purpose of this study was to (1) investigate the trends in opioid prescriptions for knee OA, (2) characterize and identify predominant opioid based medications prescribed for knee OA, and (3) identify patient- and provider-related factors influencing opioid prescribing patterns in the treatment of knee OA in the outpatient setting. METHODS: The National Ambulatory Medical Care Survey (NAMCS) was used to identify all patients in the United States who presented to an outpatient clinic for knee OA between 2007 and 2016. New opioid prescriptions were determined using a previously published algorithm. Generalized linear models were used to assess trends. RESULTS: A total of 41,389,332 patients were included, of which 12.8% were prescribed an opioid-based medication. Opioid prescription rose from 2007/2008 to 2013/2014. Analysis of the opioid type demonstrated that the prescription of hydrocodone-based medication and "other" traditional opioids followed the aforementioned trends. However, tramadol prescription demonstrated a sustained increase throughout the years peaking at 2015/2016. Patient income in the lowest quartile, a worker's compensation status, and depression were independently associated with higher odds of opioid prescription for knee OA. CONCLUSIONS: Opioid prescription for knee OA remains high. Decreases in traditional opioid prescription have been countered by increase in tramadol prescription. The risks and addictive potential of tramadol and patient and provider risk factors should be emphasized.