Table 1

Summary statistics for respiratory data October 1995–October 1997

nMean (SD) or %MedianMinimumMaximum
Male sex9472%
Age (years)9467.5 (8.2)68.24083
PEF (l/min)94224 (79)22060453
FEV1 (ml)28967 (363)8803551731
FVC (ml)281952 (762)20106903782
Reversibility916.5 (10.2)5.3-3137
Mean no. of large PEF decrements*9414 (26)2.50122
Mean no. of exacerbations943.1 (3.2)2016
Mean no. of symptomatic falls in PEF943.7 (3.7)2.5016
Mean no. of episodes of dyspnoea945.7 (5.4)3.5020
Mean no. of episodes of change in sputum§942.9 (3.4)2017
Mean no. of episodes of nasal discharge/congestion942.9 (3.6)2019
Mean no. of episodes of wheeze943.8 (4.5)2018
Mean no. of episodes of URS**942.7 (3.0)2014
  • * Large PEF decrements: PEF <20% × median value.

  • Symptomatic fall in PEFs: defined as fall in PEF 10 l/min for ≥2 days + increase in breathlessness.

  • Dyspnoea: defined as an increase in symptom.

  • § Sputum changes: defined as a change in sputum purulence or amount.

  • Wheeze: defined as an increase in wheeze or increase in tightness of chest.

  • ** URS: upper respiratory symptoms—increase in sore throat or cough.

  • FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; PEF, peak expiratory flow.