Introduction and aim A local substance misuse study and anecdotal evidence from primary care, suggested many methadone patients have respiratory disease and/or prescriptions for respiratory preparations. Anecdotal evidence from clinical colleagues supports this. With little published literature in this area, this preliminary study aimed to explore the prevalence of respiratory diseases and prescriptions for respiratory medication in drug misusers.

Method This exploratory study used a historical cohort design with matched controls. An analysis of Primary Care Clinical Informatics Unit (PCCIU) GP consultation data was conducted. The prevalence of common respiratory diseases (ever appearing in the patient's medical records) and commonly used respiratory prescriptions (in 2008) between drug misusers and matched controls (general population sample) was compared.

Results The PCCIU data contained a cohort of 18 570 patients (9285 per group), of which, 64% (n=11885) were male and 75.7% (n=14060) were aged 31–59. Results revealed an increased prevalence of chronic respiratory disease in drug misusers versus controls. Drug misusers were more likely to be prescribed chronic respiratory diseases medications than controls. These results were still significant when adjusted for smoking status, where those who had never smoked were compared to those who had ever smoked (current and ex smokers) (See Abstract S108 Table 1). Median quantity of SABA and ICS prescriptions during 2008 were also statistically significantly higher in drug misusers*. The median quantity of SABA prescribed for drug misusers were 4 (IQR 2–8) vs 3 (IQR 1–7) in controls**. The median quantity of ICS prescribed for drug misusers were 4 (IQR 2–8) vs 2 (IQR 1–5) in controls**. *Median Prescription for patients on ≥1 prescription. **p<0.001 Mann–Whitney U.

Conclusion These data suggest, drug misusers have a significantly higher prevalence of respiratory diseases and are prescribed significantly more respiratory medications than matched controls. Adjusting for smoking status, still revealed drug misusers have significantly increased odds of have a respiratory disease or being prescribed respiratory medication, indicating there may be more complex factors involved related to drug use needing further exploration. As a first stage exploratory study, we have set the scene for future work to begin to determine the potential reasons for this association.