Patient characteristics in relation to opioid exposure in a chronic non-cancer pain population

Objectives: The efficacy of long-term opioid therapy (LTOT) in treating patients with chronic non-cancer pain (CnCP) is questionable, and the potential risks of adverse effects are well established. The aims were as follows: (1) compare characteristics in patients exposed to LTOT vs non-exposed. (2) Regarding opioid-exposed patients, describe characteristics of patients with risk factors for opioid use disorder or overdose in relation to opioid dosage.

Method: A cross-sectional study was conducted at a Swedish tertiary pain rehabilitation clinic serving CnCP patients. The study population comprised 1,604 patients ≥18 years old registered in the Swedish Quality Registry for Pain Rehabilitation between 2018 and 2020. Data on dispensed opioids were extracted from the Swedish Prescribed Drug Register. Dependent variables were as follows: LTOT vs non-LTOT and exposed opioid dosage <50 mg morphine equivalent/day (MME/day) vs ≥50 MME/day.

Results: Of the included patients, 681 (42.5%) had at least one dispensation of opioids 180 days prior to assessment, 601 with a calculated opioid dosage ≥1 MME/day, and 424 (26.4%) were exposed to LTOT. The type of opioid prescribed was, in descending order, oxycodone (42.3% of all dispensations), codeine in combination with paracetamol (17.6%), tramadol (13.8%), and morphine (8.1%). A total of 89 cases had dosages of ≥50 MME/day and 430 patient dosages <50 MME/day. Patients exposed to LTOT exhibited an increased odds ratio (OR) of 2.685 (95% CI, 1.942-3.711) for concomitant use of benzodiazepines and male sex (OR, 1.694; 95% CI, 1.227-2.337). Patients receiving doses ≥50 MME/day were all, except one, exposed to LTOT. The concomitant use of benzodiazepines (OR 1.814, 95% CI 1.264-3.331) and male sex (OR, 1.777; 95% CI, 1.178-3.102) indicated a higher OR for opioid doses ≥50 MME/day.

Conclusions: LTOT strongly influenced the opioid dose. Furthermore, concomitant benzodiazepine dispensation and male sex were over-represented in patients exposed to LTOT as well as those exposed to opioid doses ≥50 MME/day.