Introduction: 14-day IV Antibiotics courses (IVAB) are a treatment option in bronchiectasis. However, assessing clinical response can be challenging due to limitations with biomarkers. The BEST score provides an additional metric for assessing response. 

Aims: i) To record changes in BEST score during exacerbations; ii) To evaluate rate of change of symptoms; iii) To identify when BEST score may influence clinical practice

Methods: BEST scores were recorded at the start of an IVAB and every 7 days during treatment. Other clinical details were recorded including the reason for the IV antibiotics.  Previous responsiveness of BEST scores were reviewed when selecting future IVAB.

Results: 51 IVAB were assessed in 22 different patients (median BSI 16; median duration 14 days). P. aeruginosa was the most common associated pathogen (51% of cases).  The median BEST scores on day 0, 7 and 14 were 14; 10.5 and 10. Using an MCID of 4, 26 patients had achieved this by day 7. However, the score had worsened to below the MCID by the end of the course in 4 cases. 29 had achieved the MCID by the end of the course (8 of whom had not achieved the MCID by day seven).  Courses were either "acute" (13), "semi-elective" (22) or "planned" (16). Significantly less patients who receivied planned IVAB achieved the MCID at the end of their course (p= 0.01 by Chi-Sq). In two cases when the patient did not achieve the MCID at the end of the course and their IVAB was changed, the MCID was subsequently achieved.

Conclusion:  Recording BEST scores can help determine the impact of a course of antibiotics and subsequent antibiotic selection.  The achievement of the MCID by day 7 is not always maintained through to the end of the course.