Chronic obstructive pulmonary disease (COPD) among opioid dependent patients in substitution treatment. A diagnostic study

Aims:To estimate the prevalence of chronic obstructive pulmonary disease (COPD) and related risk factors in persons in opioid substitution treatment (OST), to compare airflow limitation severity and age-specific COPD prevalence rates with those in the general population, and to assess the OST-patients' willingness to adopt life style changes and to use therapeutic offers for COPD management.

Methods: A cross-sectional study in a random sample of opioid dependent patients in OST was conducted in the outpatient centres for substance addiction medicine in Zurich, Switzerland. Short standardized questionnaires about drug use, smoking habits, and medical history, filled in face-to-face interviews or from medical record lookup. Additionally, lung functions were determined with spirometry without and—depending on the result—with bronchodilation.

Results: 125 participants have been included. Almost one third (30.3%-31.9% depending on spirometry quality criteria applied; 95% CI 22.6%-42.0%) of the participants with valid spirometry tests were diagnosed with COPD, half of them being of mild severity (GOLD grade 1). Mean age (± SD) in all cases with COPD was 51.0 (± 6.9) years. Smoking tobacco (92.0%) and inhalation substance use (cannabis: 97.6%, cocaine: 69.6%, heroin: 68.0%) were highly prevalent among all participants. One out of five (20.2%) of all current tobacco users was motivated to give up smoking. The participants showed considerable interest in life style changes and to use therapeutic offers for COPD management, with changing their form of substance consumption being least (41.0% interested), and pharmacological treatment most popular (72.6% interested).

Conclusions: Among patients in OST, multiple risk factors are almost ubiquitous and prevalence of COPD is high. An extensive case finding strategy would identify patients at relatively young ages and in early stages with still mild airflow limitations, thus allowing for greater effects of early interventions. Diagnostic spirometry should be considered for all individuals > 40 years who newly enter OST. Patients interested in COPD self-management or specific life style changes should be offered appropriate support.