Development of the Drug and Alcohol Respiratory Health Test

Respiratory diseases are highly prevalent among adults with substance use disorder. Inhaling drugs are risk factors, and cigarette smoking contributes to 90% of COPD cases. The substance use disorders population faces barriers to accessing healthcare, leading to under-diagnosis and including stigma, exacerbating the unmet need for effective respiratory disease management. There is no population-specific screening instrument in NHS and Third Sector addiction services. The lack of a validated screening tool means Respiratory health symptoms may be overlooked or attributed to other causes. The aim of this trial is to develop a brief Drug and Alcohol Respiratory Health Test (DARHT) and make it available for clinical assessment and medical reviews. The primary research question is to determine if the DARHT achieves satisfactory diagnostic accuracy with gold-standard spirometry. The study will be open to any enrolled adult (age \>18 years) patients at our treatment clinic (NHS secondary care) who reports inhaling (smoking) tobacco, cannabis, cocaine, opioids, or consuming alcohol in the past 28 days. Volunteer and informed and consenting participants will be invited to: (1) complete a brief study questionnaire that includes the DARHT, then take a spirometry and pulse oximetry test; (2) return to the clinic after 3-7 day to complete the DARHT with a different interviewer. Participants with a positive case evaluation on the DARHT or spirometer will be referred to primary or specialist services. The investigators will contact participants referred after 6 weeks to determine their progress and the PHQ-4 and EQ-5D-L to evaluate changes in quality of life. The first 20 participants referred to specialist care will be invited to a Lung Health Clinic where the investigators will offer a psycho-social intervention for advice and support.