PT - JOURNAL ARTICLE AU - HA Thiadens AU - GH De Bock AU - FW Dekker AU - JA Huysman AU - JC Van Houwelingen AU - MP Springer AU - DS Postma TI - Value of measuring diurnal peak flow variability in the recognition of asthma: a study in general practice AID - 10.1183/09031936.98.12040842 DP - 1998 Oct 01 TA - European Respiratory Journal PG - 842--847 VI - 12 IP - 4 4099 - http://erj.ersjournals.com/content/12/4/842.short 4100 - http://erj.ersjournals.com/content/12/4/842.full SO - Eur Respir J1998 Oct 01; 12 AB - In this study we analysed the value of measuring diurnal peak flow variability (DPV) in general practice for diagnosing asthma or chronic obstructive pulmonary disease (COPD). One hundred and eighty-two subjects, aged 18-75 yrs, with undiagnosed asthma or COPD, presenting with a persistent cough recorded a peak flow diary twice daily for 2 weeks. A diagnosis of asthma or COPD was based on the recurrence of airway symptoms in the past year accompanied by spirometric measurements and a provocative dose of methacholine causing a 20% fall in forced expiratory volume in one second. DPV was expressed as amplitude percentage highest of the day. Cut-off values of 15% and 20% (DPV15%, DPV20%) were employed and the number of days that these values were reached, was assessed. The influence of age, sex and pack-years smoking on DPV was analysed by logistic regression. The a priori probability to have asthma (n=69) or COPD (n=12) was 45% (81/182) and increased to >70% with a DPV20% for at least 3, and a DPV15% for at least 4 days. Scoring formulas for asthma (DPV15% (number of days present) + 4 (if female sex)) and for asthma and COPD combined (8x DPV15% (number of days present) + 24 (if female sex) + pack-years smoking) predicted which subjects were at risk for having asthma (or COPD). Simple formulas based on the number of days with diurnal peak flow variability at 15%, female sex and pack-years can predict which patients with persistent cough are likely to have asthma or chronic obstructive pulmonary disease.