Asthma rehabilitation at high vs. low altitude: randomized parallel-group trial

Abstract

BackgroundTo investigate the effect of asthma rehabilitation at high altitude (3100\u2009m, HA) compared to low altitude (760\u2009m, LA).MethodsFor this randomized parallel-group trial insufficiently controlled asthmatics (Asthma Control Questionnaire (ACQ) >\u20090.75) were randomly assigned to 3-week in-hospital rehabilitation comprising education, physical-&breathing-exercises at LA or HA. Co-primary outcomes assessed at 760\u2009m were between group changes in peak expiratory flow (PEF)-variability, and ACQ) from baseline to end-rehabilitation and 3\u2009months thereafter.Results50 asthmatics were randomized [median (quartiles) LA: ACQ 2.7(1.7;3.2), PEF-variability 19%(14;33); HA: ACQ 2.0(1.6;3.0), PEF-variability 17%(12;32)].The LA-group improved PEF-variability by median(95%CI) -7%(−\u200914 to 0, p\u2009=\u20090.033), ACQ −\u20091.4(−\u20092.2 to −\u20090.9, p\u2009<\u20090.001), and after 3\u2009months by −\u20093%(−\u200918 to 2, p\u2009=\u20090.103) and\u2009−\u20090.9(−\u20091.3 to −\u20090.3, p\u2009=\u20090.002). The HA-group improved PEF-variability by −\u200910%(−\u200921 to −\u20093, p\u2009=\u20090.004), ACQ −\u20091.1(−\u20091.3 to −\u20090.7, p\u2009<\u20090.001), and after 3\u2009months by −\u20099%(−\u200910 to −\u20093, p\u2009=\u20090.003) and\u2009−\u20090.2(−\u20090.9 to 0.4, p\u2009=\u20090.177). The additive effect of HA vs. LA directly after the rehabilitation on PEF-variability was −\u20096%(−\u200914 to 2), on ACQ 0.3(−\u20090.4 to 1.1) and after 3\u2009months −\u20095%(−\u200914 to 5) respectively 0.4(−\u20090.4 to 1.1), all p\u2009=\u2009NS.ConclusionAsthma rehabilitation is highly effective in improving asthma control in terms of PEF-variability and symptoms, both at LA and HA similarly.Trial registrationClinicaltrials.gov: NCT02741583, Registered April 18, 2016.