Validating and Developing the Bronchiectasis Exacerbation and Symptom Tool

A newly developed self-report diary, the Bronchiectasis Exacerbation and Symptoms Tool (BEST), was responsive at both onset and recovery from exacerbations.

A newly developed self-report diary, the Bronchiectasis Exacerbation and Symptoms Tool (BEST), demonstrated concurrent validity with established health questionnaires and was responsive at both onset and recovery from exacerbations, according to study results published in Respiratory Research. Findings indicate that the BEST diary may be useful in detection and characterization of exacerbations in bronchiectasis clinical trials.

Recurrent bronchiectasis exacerbations are related to disease progression, deterioration of lung function, impaired quality of life, and increased mortality. Patient-report diaries have been shown to improve detection and treatment of episodes of exacerbation in other conditions, including chronic obstructive pulmonary disease (COPD).

This prospective observational study, conducted at Ninewells Hospital, Dundee, United Kingdom, was designed to develop and validate a novel symptom diary for detection of bronchiectasis exacerbation. All participants (N=21) had computed tomography-confirmed bronchiectasis, were symptomatic, and had experienced ≥1 documented bronchiectasis exacerbation in the previous 12 months.

Symptoms reported using the BEST diary were based on consensus definitions for exacerbation in bronchiectasis, including cough, sputum color, sputum volume, fatigue, dyspnea, and systemic disturbance. Total possible BEST score for all symptom ratings ranged from 0 to 26. Participants recorded presence and severity of exacerbation symptoms daily for up to 6 months. Any reported episodes of acute exacerbation were treated using the standard of care, a 14-day course of antibiotics. Of the initial 21 patients, 19 completed all 6 months of diary entries.

The minimal clinically important difference (MCID) for BEST was calculated using distribution-based methods and correlation coefficients between symptom scores and measures with established MCIDs (eg, validated COPD assessment tests), which were used as “anchors” for estimating changes in BEST score that equated to MCIDs. BEST showed good correlation with established, validated questionnaires and health status measures (COPD Assessment Test: r=0.61; P =.0037; Leicester Cough Questionnaire: r=-0.52; P =.0015; St. George’s Respiratory Questionnaire total score: r=0.61; P <.0001; and symptom domain: r=0.52; P =.015), and the 6-minute walk test: r=-0.46; P =.037).

The mean baseline BEST score was 7.1 points, the peak mean symptom score during exacerbation was 16.4, and the mean change from baseline to exacerbation was 9.1 points. The mean exacerbation duration, based on time until return to baseline symptom level, was 15.3 days. An MCID of 4 points on BEST was proposed based on study results, resulting in sensitivity of 93% and specificity of 66% for detection of treated exacerbations.

Over several days leading up to a reported and confirmed exacerbation, participants showed increases in mean BEST score of ≥4 points (P <.0001 by paired t test), with a peak mean symptom score during exacerbation of 16.4 (range, 12-22). Diary scores indicating a sustained increase of ≥3 points for ≥48 hours were used to identify 23 unreported and untreated exacerbation episodes in 13 participants. Mean change from baseline in an unreported exacerbation episode was 4.7 points ( range, 3-8). Unreported exacerbations were less severe and of shorter duration than reported exacerbations.

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The investigators concluded, “The BEST symptom diary shows convergent validity with existing health questionnaires and is responsive at onset and recovery from exacerbation. A daily diary such as BEST may be useful to capture and characterise exacerbations in future trials.”

Disclosure: Study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.


Artaraz A, Crichton ML, Finch S, et al. Development and initial validation of the bronchiectasis exacerbation and symptom tool (BEST). Respir Res. 2020;21(1):18.