The oral AntibioticS approprIateness score (OASIS) - A novel scoring system to assess antibiotic route in pulmonary exacerbations of cystic fibrosis (CF)

Objectives: Prompt antibiotic treatment for CF pulmonary exacerbations probably preserves lung function and prolongs survival. Oral administration is common, but choice can be determined by resource and social factors as well as clinical need. We developed an objective score to support appropriate oral antibiotic choice in CF. Methods: Adult CF patients underwent baseline assessment and follow up for 1 year. Clinical factors associated with choice of antibiotic route for first exacerbation were identified by logistic regression and comprised the Oral AntibioticS ApproprIateness Score (OASIS). The relationship between OASIS, treatment choice and exacerbation rate was determined. Results: Of 254 patients (31±9yrs), 198 (78%) had > 1 exacerbation. Factors associated with intravenous antibiotics for first exacerbation were baseline FEV 1 <47% predicted, IV antibiotics in previous year, chest symptoms, Ps. aeruginosa / gram –ve bacteria on sputum culture. OASIS allocates 1 point per factor, range 0 (good) to 4 (bad). Patients with lower OASIS had less annual exacerbations (0, 2.2; 1, 2.7; 2, 2.9; 4, 3.5; 4, 4.4, p<0.001) and were less likely to re-exacerbate following a course of oral antibiotics (p=0.02) OASIS Score 0 1 2 3 4 Total Number of Patients Further exacerbation within 52 weeks No 5(31.3%) 10(25.0%) 8(19.0%) 2 (6.9%) 0(0.0%) 25(18%) Yes 11(68.8%) 30(75.0%) 34(81.0%) 27(93.1%) 12(100%) 114(82.0%) Total of Patients 16 40 42 29 12 139 OASIS score and outcomes after oral antibiotics Conclusion: OASIS identifies patients with exacerbations more likely to respond to oral antibiotics. This use is currently undergoing further validation.