Predictors of asthma control in everyday clinical practice in Switzerland

Abstract

Objective:

To identify predictors of improved asthma control under conditions of everyday practice in Switzerland.

Research design and methods:

A subgroup of 1380 patients with initially inadequately controlled asthma was defined from a cohort of 1893 asthmatic patients (mean age 45.3 ± 19.2 years) recruited by 281 office-based physicians who participated in a previously-conducted asthma control survey in Switzerland. Multiple regression techniques were used to identify predictors of improved asthma control, defined as an absolute decrease of 0.5 points or more in the Asthma Control Questionnaire between the baseline (V1) and follow-up visit (V2).

Results:

Asthma control between V1 and V2 improved in 85.7%. Add-on treatment with montelukast was reported in 82.9% of the patients. Patients with worse asthma control at V1 and patients with good self-reported adherence to therapy had significantly higher chances of improved asthma control (OR = 1.24 and 1.73, 95% CI 1.18–1.29 and 1.20–2.50, respectively). Compared to adding montelukast and continuing the same inhaled corticosteroid/fixed combination (ICS/FC) dose, the addition of montelukast to an increased ICS/FC dose yielded a 4 times higher chance of improved asthma control (OR = 3.84, 95% CI 1.58–9.29). Significantly, withholding montelukast halved the probability of achieving improved asthma control (OR = 0.51, 95% CI = 0.33–078). The probability of improved asthma control was almost 5 times lower among patients in whom FEV₁ was measured compared to those in whom it was not (OR = 0.23, 95% CI = 0.09–0.55). Patients with severe persistent asthma also had a significantly lower probability of improved control (OR = 0.15, 95% CI = 0.07–0.32), as did older patients (OR = 0.98, 95% CI = 0.97–0.99). Subgroup analyses which excluded patients whose asthma may have been misdiagnosed and might in reality have been chronic obstructive pulmonary disease (COPD) showed comparable results.

Conclusions:

Under conditions of everyday clinical practice, the addition of montelukast to ICS/FC and good adherence to therapy increased the likelihood of achieving better asthma control at the follow-up visit, while older age and more severe asthma significantly decreased it.

Keywords: :

• Asthma control
• Asthma Control Questionnaire (ACQ)
• Inhaled corticosteroids
• Leukotriene receptor antagonists
• Physician survey

Transparency

Declaration of funding

The initial survey, the present additional analysis and the assistance in the preparation of the manuscript by Dr Philippe Kress were funded by an unrestricted research grant from MSD-Chibret AG, Switzerland.

Declaration of financial/other relationships

A.B.T. has disclosed that she has received a speakers bureau honorarium from MSD-Chibret AG. J.D.L. is a recipient of unregistered research grants from MSD and speaker bureau honorarium from AstraZeneca, GSK and MSD. D.P. has disclosed consultant arrangements with Altana, Boehringer-Ingelheim, GlaxoSmithKline, Ivax and Pfizer; that he or his team have received grants and research support for research in respiratory disease from: Altana Pharma, AstraZeneca, Boehringer-Ingelheim, GlaxoSmithKline, Ivax, MSD, Novartis, Pfizer, and Schering Plough; and that he has been on the speakers bureau for Altana Pharma, Boehringer-Ingelheim, GSK, MSD and Pfizer. C.S.-S. has disclosed that she has received a research grant and is an advisory board member for AstraZeneca (Switzerland); and has received speakers bureau honoraria from Boehringer Ingelheim, AstraZeneca, MSD-Chibret, Pfizer, Novartis, and GSK (Switzerland). J.H.W. and F.S. have disclosed that they have no relevant financial relationships.

Acknowledgements

The authors thank Dr Philippe Kress (Kressmed, Glattbrugg, Switzerland) for his assistance in preparing the manuscript (with financial support provided by MSD-Chibret AG).