Opioid abuse: A detailed examination of cost drivers over a 24-month follow-up period

Abstract

BACKGROUND: Previous work has documented the considerable economic burden associated with opioid abuse, dependence, and overdose/poisoning (hereafter, "abuse"). Recent analyses have provided insights into the trajectory and drivers of the excess costs of abuse both before and after diagnosis, showing the important role of other substance abuse, mental health issues, and painful conditions. OBJECTIVE: To build on the recently published study by Kirson et al. (2017) and extend its findings by (a) evaluating the trajectory of excess costs of abuse for an additional year after an incident abuse diagnosis and (b) exploring the diagnosis-level drivers of excess costs over time in greater detail. METHODS: Using administrative medical and pharmacy claims, which included payment amounts, for beneficiaries covered by large self-insured companies throughout the United States, abusers were matched to controls using the same methods as in Kirson et al. Excess health care costs were assessed over a 24-month follow-up period, which comprised the 6 months before the initial abuse diagnosis and the 18 months after. Drivers of excess costs were then evaluated by diagnosis (grouped at the 3-digit ICD-9-CM level). RESULTS: This study analyzed 9,345 matched pairs of abusers and nonabusers. Similar to the previous study, mean per-patient excess health care costs were found to rise considerably leading up to and shortly after the incident diagnosis of abuse, reaching $15,764 over the first half of the follow-up period. Over the newly extended follow-up period (months 6 to 18 after diagnosis), excess costs remained elevated ($7,346) and did not return to baseline levels. Over time, an increasing share of excess costs was observed for outpatient services and prescription drug use, relative to acute care settings. A detailed examination of cost drivers suggested elevated costs in several clinical categories (e.g., gastrointestinal, respiratory conditions) beyond those previously identified. CONCLUSIONS: This research finds that the excess medical costs of abuse extend for at least 1 more year than previously documented, reflecting the need for considerable follow-up care over time. The identification of several other clinical categories with elevated excess costs suggests important areas for future research into the interaction of opioid abuse with the management of other conditions.