A simple score for future risk prediction in patients with controlled asthma who undergo a guidelines-based step-down strategy.

Publication date: Available online 25 October 2018

Source: The Journal of Allergy and Clinical Immunology: In Practice

Author(s): Luis Pérez de Llano, Juan Luis García-Rivero, Isabel Urrutia, Eva Martínez-Moragón, Jacinto Ramos, Pilar Cebollero, Francisco Carballada, Marina Blanco, María del Carmen Vennera, María Merino, Yolanda Torralba García, NR, Vicente Plaza

Abstract

Background

The minimum controlling dose of treatment must be established in asthma patients, but the outcome of step-down is unpredictable.

Objective

To identify factors associated with risk of control loss when stepping-down asthma treatment and to develop a score to predict this risk.

Methods

Prospective, multicenter study including adults with well-controlled asthma. Treatment was stepped-up or stepped-down over a 12-month period to maintain asthma control. We determined associations between clinical and functional variables and step-down failure. Finally, we derived a score to predict loss of control in one cohort and validated it in an independent cohort.

Results

The derivation cohort consisted of 228 patients, 218 completed at least one step-down episode and a total of 495 step-down episodes were evaluated. A medical-record documented post-bronchodilator spirometry result of < 70% FEV1/FVC (OR = 2.08; 95% CI: 1.26–3.43), current FEV1 < 80% (OR = 1.80; 95% CI: 1.03–3.14), ≥1 severe exacerbation in the previous 12 months (OR = 2.43; 95% CI: 1.48–4.01) and ACT score < 25 (OR = 2.30; 95% CI: 1.35–3.92) were independently associated with failure. The score showed an AUC of 0.690 (95% CI: 0.633-0.747; p < 0.05) in the derivation cohort and 0.76 (95% CI: 0.643-0.882; p <0.001) in a validation cohort of 114 patients. A score < 4.5 implies a low risk of failure (< 20%) whereas a score >8 implies a high risk (>40%).

Conclusion

This score can facilitate the prediction of step-down failure before medication taper in well-controlled asthma patients.