Association of levels of opioid use with pain and activity interference among patients initiating chronic opioid therapy: a longitudinal study.
Little is known about long-term pain and function outcomes among patients with chronic noncancer pain initiating chronic opioid therapy (COT). In the Middle-Aged/Seniors Chronic Opioid Therapy study of patients identified through electronic pharmacy records as initiating COT for chronic noncancer pain, we examined the relationships between level of opioid use (over the 120 days before outcome assessment) and pain and activity interference outcomes at 4- and 12-month follow-ups. Patients aged 45+ years (N = 1477) completed a baseline interview; 1311 and 1157 of these comprised the 4- and 12-month analysis samples, respectively. Opioid use was classified based on self-report and electronic pharmacy records for the 120 days before the 4- and 12-month outcome assessments.