Improving opioid substitution therapy in the acute hospital setting: implementation of a best practice guideline

Delayed provision of opioid substitution therapy (OST) in acute hospitals contributes to patient distress, opioid withdrawal and discharge against medical advice (DAMA). We aimed to improve access to opioid substitution therapy (OST) for hospital inpatients, using the iHOST ('improving hospital opioid substitution therapy') clinical guidelines, developed through a deliberative consensus process in partnership with clinical, academic and peer experts with professional body oversight.

This pre-post quality improvement study evaluates implementation of the iHOST guideline at a tertiary hospital serving inner city London, UK between 2021 and 2023. Clinical records of all patients administered OST in the 12 months before and 11 months after the policy's introduction were evaluated for measures of process (reducing urine drug screening, improving time-to-administration), balancing (avoiding emergency naloxone administration, avoiding increased mortality) and outcome (discharge against medical advice).

Among 259 patients pre-policy and 194 post-policy, the median time to first methadone dose fell from 18.1 hours to 14.8 hours and the proportion of patients waiting more than 24 hours reduced from 32% to 21% (OR 0.57, 95% CI 0.37 to 0.88). Urine drug screening was one-sixth as likely to be performed on admission. There was no change in the likelihood of discharge against medical advice, which occurred for 24% of admissions during both periods (p=0.96). Naloxone was required for only 2% of admissions (five pre-policy, four times post p=1.00), indicating no compromise of patient safety.

Implementing the iHOST guideline successfully reduced unnecessary delays to methadone administration without increasing the risk of opioid toxicity. While high rates of DAMA, even after improving access to OST, point to an ongoing need for patient-centred engagement strategies, successful implementation of the iHOST guideline supports its wider use: it is now under evaluation in two additional hospitals, after which it will be optimised to assess its utility for nation-wide practice.