Winner of the SSA Fred Yates Prize for Early Career Researchers

Dr Emmert Roberts is a Senior Clinical Lecturer in Addiction Psychiatry at King’s College London and a Consultant Addiction Psychiatrist at the South London and the Maudsley NHS Foundation Trust. He is currently a National Institute for Health and Care Research (NIHR) Advanced Fellow and a Commonwealth Fund Senior Harkness Fellow exploring ways to reduce harm due to drug and alcohol use by harnessing administrative data. 

Abstract

Prediction of 6-month individualised mortality risk in Opioid Use Disorder

Aims: People with opioid use disorder have substantially higher standardised mortality rates compared with the general population. However, lack of individualised prognostic information presents challenges in personalisation of addiction treatment delivery. We aimed to develop and validate the first prognostic models to estimate 6-month all-cause and drug-related mortality risk for people diagnosed with opioid use disorder using indicators recorded at baseline assessment in addiction services in England. 

Methods: Thirteen candidate prognostic variables, including sociodemographic, injecting status and health factors, were identified from nationally linked addiction treatment, hospital admission and death records from 1 April 2013 to 1 April 2022. Multivariable Cox regression models were developed with a fractional polynomial approach for continuous variables. Validation was undertaken using bootstrapping. Discrimination was assessed using Harrel’s C and D-statistics alongside examination of observed-to-predicted event rates and calibration curve slopes. 

Results: Data were available for 236,064 people with opioid use disorder, with 2,427 deaths due to any cause, including 1,289 due to drug-related causes. Both models demonstrated good optimism-adjusted discrimination and calibration. All-cause and drug-related models, respectively, demonstrated Harrell’s C statistics of 0.73 (95%CI 0.71–0.75) and 0.74 (95%CI 0.72–0.76), D-statistics of 1.01 (95%CI 0.95–1.08) and 1.07 (95%CI 0.98–1.16) and calibration slopes of 1.01 (95%CI 0.95–1.08) and 1.01 (95%CI 0.94–1.10). 

Conclusions: We developed and validated Roberts’ OUD (ROUD) mortality risk score, the first international models to accurately quantify individualised absolute 6-month mortality risks in people with opioid use disorder presenting to addiction services. These models are now publicly available and will be demonstrated in this session. Independent validation is warranted to ensure these models have the optimal utility to assist future policy, commissioning and clinical decision making.