Screening heroin smokers attending community drug clinics for change in lung function: A cohort study

Background: Heroin smokers have high rates of chronic obstructive pulmonary disease (COPD), respiratory morbidity, hospital admission and mortality. We assessed the natural history of symptoms and lung function in this population over time.

Methods: A cohort of heroin smokers with COPD was followed for 18-24 months. At baseline and follow-up, respiratory symptoms were measured by Medical Research Council Dyspnoea Scale (MRC) and COPD Assessment Tool (CAT), and post-bronchodilator spirometry was performed. Frequency of healthcare-seeking episodes was extracted from routine health records. Parametric, non-parametric and linear regression models were used to analyse the change in symptoms and lung function over time.

Results: Of 372 participants originally recruited, 161 were assessed at follow-up (mean age 51.0 [SD 5.3], 74 [46%] female) and 106 participants completed post bronchodilator spirometry. All participants were current or previous heroin smokers and 122 (75.8%) had smoked crack. Symptoms increased over time (MRC score by 0.48/year (p<0.001) and CAT score by 1.60/year (p<0.001). Forced expiratory volume in 1 second (FEV1) declined annually by 90ml (SD 190, p<0.001). This deterioration was not associated with change in tobacco or heroin smoking status or use of inhaled medications.

Conclusion: Heroin smokers experience a high and increasing burden of chronic respiratory symptoms, and a decline in FEV1 that exceeds the normal age-related decline observed amongst tobacco smokers with COPD and healthy non-smokers. Targeted COPD diagnostic and treatment services hosted within opiate substitution services could benefit this vulnerable, relatively inaccessible, and underserved group of people.