Opioid use after surgical treatment in the Danish population—Protocol for a register-based cohort study

Abstract

Background: Over the past 25 years, global opioid consumption has increased. Denmark ranks fifth in opioid use globally, exceeding other Scandinavian countries. Postsurgical pain is a common reason for opioid prescriptions, but opioid use patterns after patient discharge from the hospital are unclear. This study examines trends in opioid prescription among Danish surgical patients over a year. Methods: This register-based cohort study will use data from Danish governmental databases related to patients undergoing the 10 most frequent surgical procedures in 2018, excluding cancer-related and minor procedures. The primary outcome will be the dispensed postoperative opioid prescriptions at retail pharmacies over four quar- ters. Secondary analyses will include associations with sex, age, education attainment, and oral morphine equivalent quotient. Surgical treatments and diagnoses will be identified using NOMESCO procedure codes and ICD-10 codes. Opioids will be iden- tified by ATC codes N02A and R05DA04. Subjects will be classified as preoperative opioid consumers or non-opioid consumers based on opioid prescriptions redeemed in the 6 months before surgery. Discussion: The study will use extensive national register-based data, ensuring con- sistent data collection and enhancing the generalizability of the findings to similar healthcare systems. The study may identify high-risk populations for long-term opi- oids and provide information to support opioid prescribing guidelines and public health policies.