Predicting worsening asthma control following the common cold

Abstract

The asthmatic response to the common cold is highly variable, and early characteristics that predict worsening of asthma control following a cold have not been identified. In this prospective multicentric cohort study of 413 adult subjects with asthma, the mini-Asthma Control Questionnaire (mini-ACQ) was used to quantify changes in asthma control and the Wisconsin Upper Respiratory Symptom Survey-21 (WURSS-21) to measure cold severity. Univariate and multivariable models were used to examine demographic, physiological, serological and cold-related characteristics for their relationship to changes in asthma control following a cold. Clinically significant worsening of asthma control was observed following a cold (mean+/-SD increase in mini-ACQ score of 0.69+/-0.93). Univariate analysis demonstrated that season, centre location, cold duration and cold severity measurements were all associated with a change in asthma control. Multivariable analysis of the covariates available within the first 2 days of cold onset revealed that the day 2 and cumulative sum of day 1 and 2 WURSS-21 scores were significant predictors of the subsequent changes in asthma control. In asthmatic subjects, cold severity within the first 2 days can be used to predict subsequent changes in asthma control. This information may help clinicians prevent deterioration in asthma control following a cold.

Figures

Figure 1. Asthmatics with a cold demonstrate an increased WURSS-21 score

In A-B, WURSS-21 scores for asthmatics with a cold (Cold) and without a cold (Non-cold). Day 1 indicates the day of cold onset. All values represent mean ± SD and a significant difference between cohorts using the independent groups t-test is indicated (*).

Figure 2. Asthmatics with a cold demonstrate worsening asthma control

Pre-cold, Post-cold day 7, and Post-cold day 14 mini-ACQ scores are shown for the cohort of cold subjects with complete mini-ACQ data. For each box plot the horizontal line represents the median, the box stretches from the 25th to the 75th percentile of values, the whiskers end at the 95% confidence intervals and outliers are indicated by individual circles. p-values for each comparison (using repeated measures ANOVA) are shown.