BACKGROUND: etiological investigations are not done for all adult patients with bronchiectasis because of the availability and interpretation of tests. The aim of the study was to elaborate a score to identify patients at high risk of having cystic fibrosis or primary ciliary dyskinesia (CF/PCD), which require appropriate management. METHODS: diagnostic work-ups were carried out on a French monocenter cohort, and results were subjected to logistic-regression analyses to identify the independent factors associated with CF/PCD diagnosis and, thereby, elaborate a score to validate in a second cohort. RESULTS: among 188 patients, 158 had no obvious diagnosis and were enrolled in the algorithm-construction group. In multivariate analyses, age at symptom onset (8.69 (2.10-35.99); p = 0.003), chronic ENT symptoms or diagnosed sinusitis (10.53 (1.26-87.57); p = 0.03), digestive symptoms or situs inversus (5.10 (1.23-21.14); p = 0.025), and Pseudomonas. aeruginosa and/or Staphylococcus aureus isolated from sputum (11.13 (1.34-92.21); p = 0.02) are associated with CF or PCD. Receiver operating characteristics curve analysis, using a validation group of 167 patients with bronchiectasis, confirmed the score's performance with AUC 0.92 (95% CI: 0.84-0.98). CONCLUSIONS: a clinical score may help identify adult patients with bronchiectasis at higher risk of having CF or PCD.
