Determinants of response to fluticasone propionate and salmeterol/fluticasone propionate combination in the Gaining Optimal Asthma controL study

Background

During the Gaining Optimal Asthma controL study, 3416 patients with uncontrolled asthma were randomized to receive salmeterol/fluticasone propionate combination (SFC) or fluticasone propionate (FP) for 1 year. Approximately two thirds of patients achieved well-controlled (WC) asthma, and one third continued to have asthma that was not well controlled (NWC).

Objective

This analysis aimed to (1) identify factors influencing treatment response and (2) assess the clinical benefits of SFC and FP in patients with NWC asthma.

Methods

Logistic regression analysis was used to investigate whether covariates influenced the achievement of at least WC asthma in the study population. In patients with NWC asthma, predefined criteria were used to assess improvements in 6 clinical outcomes.

Results

Factors affecting the probability of having NWC asthma included smoking status (current vs never: odds ratio [OR], 2.757; 95% CI, 2.061−3.689; P < .0001; former vs never: OR, 1.274; 95% CI, 1.031−1.574; P = 0.0273), sex (women vs men: OR, 0.652; 95% CI, 0.527–0.806; P < .0001), history of inhaled corticosteroid use (no history vs history: OR, 0.546; 95% CI, 0.437−0.683; P < .0001), and treatment (FP vs SFC: OR, 1.972; 95% CI, 1.686–2.308; P < .0001). Of patients with NWC asthma, 86% to 96% showed improvements in 1 or more clinical outcomes.

Conclusion

It is imperative for good asthma control that patients stop smoking. Patients who did not have at least WC asthma demonstrated clinical improvements in individual asthma outcomes.

Clinical implications

Although not all patients can achieve guideline-defined control, long-term treatment with SFC or FP is associated with clinical improvements in nearly all patients, regardless of smoking history or inhaled corticosteroid use.

Key words: Asthma, salmeterol/fluticasone propionate combination, asthma control, treatment response, smoking

Abbreviations used: AQLQ, Asthma quality of life questionnaire, BDP, Beclomethasone dipropionate, FP, Fluticasone propionate, GOAL, Gaining Optimal Asthma controL, GR, Glucocorticoid receptor, ICS, Inhaled corticosteroid, NWC, Not well controlled, OR, Odds ratio, PEF, Peak expiratory flow, PEFR, Peak expiratory flow rate, SFC, Salmeterol/fluticasone propionate combination, TC, Total control, WC, Well controlled