Development of a brief questionnaire (ICQ-S) to monitor inhaled corticosteroid side-effects in clinical practice

Abstract

Side-effect concerns impede adherence with inhaled corticosteroids (ICS) and often underlie poor asthma control. We developed a brief version (ICQ-S) of the 57-item Inhaled Corticosteroids side-effect Questionnaire (ICQ) to facilitate side-effect monitoring in busy clinics. Part 1: After completion by 482 patients with doctor-diagnosed asthma, each ICQ item underwent item reduction analysis. Part 2: Patients prescribed ICS for asthma completed the ICQ at baseline (BL), ICQ-S at day 14 (D14) and day 28 (D28), and 6-item Asthma Control Questionnaire (ACQ) and Mini Asthma Quality of Life Questionnaire (MiniAQLQ) at BL, D14 and D28. 14-day test-retest reliability was assessed by intraclass correlation coefficient (ICC) between ICQ-S scores and internal consistency by Cronbach's alpha (α) coefficient and item-total correlations of ICQ-S. Criterion validity was assessed by correlations (Spearman's rho) between ICQ and ICQ-S total score. Patients reported duration and difficulty of ICQ-S completion at D28. Part 1: The ICQ-S consists of fifteen local/systemic ICS side-effects of similar range to the full ICQ. Part 2: 62 asthma patients (mean ACQ score 0.79 ± SD 0.83) prescribed daily ICS [BDP-equivalent median dose 1000 μg (IQR: 500, 1000)] participated. ICC between ICQ-S scores was 0.90. All item-total correlations were rho ≥ 0.20. The ICQ-S demonstrated criterion validity, for example, ICQ and ICQ-S were strongly associated (rho = 0.86). 81% of patients completed the ICQ-S within 5 minutes and 97% found completion 'not difficult'. The ICQ-S is a brief, patient-friendly tool with good reliability and validity, which may be useful for monitoring ICS side-effects in clinical practice.