Pneumotoxicity ASSociated With Rheumatological Drugs (PASSWRD) – A modified Delphi

<bold>Background:</bold> Drugs used to treat rheumatological disease may be associated with pneumotoxicity, but little is known about associated risk factors. <bold>Aims:</bold> To derive majority (defined as >70%) agreement from expert rheumatologists and pulmonologists on their perceived risk factors for drug-induced pneumotoxicity in patients with rheumatological disease. <bold>Methods:</bold> A modified international Delphi. Tier 1 to determine patient-level and drug specific variables physicians perceive are associated with risk of pneumotoxicity. Tier 2 to stratify the risk associated with the Tier-1 derived variables. Tier 3 to internally validate exemplar cases into risk categories. <bold>Results:</bold> 134 pulmonologists and 49 rheumatologists responded to tier 1. 157 completed all tiers. After tier 1 the perceived risk factors included: drug; history of drug-induced pneumotoxicity; age; rheumatological disease type and activity; renal function; presence, nature, severity and progression of pre-existing interstitial lung disease (ILD). Tier 2 data stratified these variables e.g. never v current smoking was perceived as low and high risk respectively. After tier 3 validation an example of a perceived high risk case is a 75yr old smoker with high-activity rheumatoid arthritis (RA) with severe, progressive ILD being started on methotrexate. A perceived low risk case is a 75yr old smoker with moderate-activity RA and emphysema with no cardiac or renal disease and no pre-existing ILD being started on rituximab. <bold>Conclusion:</bold> This Delphi exercise has defined and stratified the perceived risk factors for developing drug-induced pneumotoxicity. A derived risk-prediction tool will be used to validate these perceived risk factors in clinical practice.