Detection of exacerbations in asthma based on electronic diary data: results from the 1-year prospective BIOAIR study
Kupczyk, M.; Haque, S.; Sterk, P.J.; Niżankowska-Mogilnicka, E.; Papi, A.; Bel, E.H.; Chanez, P.; Dahlén, B.; Gaga, M.; Gjomarkaj, M.; Howarth, P.H.; Johnston, S.L.; Joos, G.F.; Kanniess, F.; Tzortzaki, E.; James, A.; Middelveld, R.J.M.; Dahlén, S-Erik.; Weersink, E.; Papadopoulos, N.; Oikonomidou, E.; Zervas, E.; Contoli, M.; Pauwels, R.A.; Brusselle, G.; de Rudder, I.; Schelfhout, V.; Richter, K.; Gerding, D.; Magnussen, H.; Siafakas, N.M.; Samara, K.; Plataki, M.; Papadopouli, E.; Szczekli
Thorax 68(7): 611-618
2013
ISSN/ISBN: 0040-6376 PMID: 23564399 DOI: 10.1136/thoraxjnl-2012-201815Document Number: 252975
Objective measures are required that may be used as a proxy for exacerbations in asthma. The aim was to determine the sensitivity and specificity of electronic diary data to detect severe exacerbations (SEs) of asthma. A secondary aim was to identify phenotypic variables associated with a higher risk of exacerbation. In the BIOAIR study, 169 patients with asthma (93 severe (SA); 76 mild to moderate (MA)) recorded lung function, symptoms and medication use in electronic diaries for 1 year. Data were analysed using receiver-operator characteristics curves and related to physician-diagnosed exacerbations. Medical history and baseline clinical data were used to assess risk of exacerbation. Of 122 physician-diagnosed exacerbations, 104 occurred in the SA group (1.1 per patient/year), 18 in the MA group (0.2 per patient/year) and 63 were severe using American Thoracic Society/European Respiratory Society criteria. During exacerbations, peak expiratory flow (PEF) and forced expiratory volume in 1 s significantly decreased, whereas day and night symptoms significantly increased. An algorithm combining a 20% decrease in PEF or a 20% increase in day symptoms on 2 consecutive days was able to detect SEs with 65% sensitivity and 95% specificity. The strongest risk factors for SEs were low Asthma Control Questionnaire score, sputum eosinophils ≥ 3%, body mass index >25 and low quality of life (St George's Respiratory Questionnaire), with ORs between 3.61 and 2.22 (p<0.05). Regular electronic monitoring of PEF and asthma symptoms provides an acceptable sensitivity and specificity for the detection of SEs and may be suitable for personal internet-based monitoring of asthma control.