Prevalence of physical co-morbidities in older patients on prescribed opioid agonist treatment: A narrative systematic review

Background: The population prescribed Opioid Agonist Treatment (OAT) is ageing whilst additionally experiencing the associated effect of premature ageing. The population are, therefore, expected to experience more mental and physical health comorbidities. People experience more physical health problems as they age, and the number of patients treated with OAT increases. Services must be aware of the extent of physical health comorbidities affecting these patients and consider the holistic health of patients. Aims: To identify the types and prevalence of physical health comorbidities in patients aged 35 years or older who are prescribed OAT. Methods: A systematic literature search was conducted using Medline, Embase and PsycINFO between inception and April 2023. The study inclusion criteria comprised patients aged 35 years and older, prescribed OAT (methadone or buprenorphine) and physical health condition(s). The protocol was registered with PROSPERO (CRD42021250035). Eligible studies were analysed to determine the prevalence of reported physical health comorbidities and primary factors affecting exposed patients. Results: Existing published evidence is sparse, with six papers meeting the criteria. From the literature, only three comorbidities were identified. Pain is recognised as the most researched comorbidity, with four studies (66%), and respiratory and liver were identified in one study (16.5%). Comparison is difficult due to the varied terminology and diagnostics used. Conclusions: There is a knowledge gap in the research examining the physical health comorbidities affecting older patients prescribed OAT