Can a normal peak expiratory flow exclude severe chronic obstructive pulmonary disease?

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is underdiagnosed. One barrier to diagnosis is the limited availability of spirometry testing, but in adults at risk for COPD, a normal pre-bronchodilator (pre-BD) peak expiratory flow (PEF) may rule out clinically significant COPD. OBJECTIVE: To identify post-BD airway obstruction using data from 13 708 individuals aged >or=40 years from the PLATINO and BOLD studies. METHODS: We evaluated different cut-off points of pre-BD. The PEF was obtained from a diagnostic-quality spirometer (not a mechanical PEF meter). At least one of the following COPD risk factors was present in 77% of the subjects: chronic respiratory symptoms; exposure to tobacco smoke, biomass smoke or dust in the workplace; or a previous diagnosis of asthma, COPD, emphysema or chronic bronchitis. RESULTS: Although the positive predictive value was low as expected, a pre-BD PEF of >or=70% predicted effectively ruled out Stages III and IV COPD of the Global Initiative for Chronic Obstructive Lung Disease. Among those with at least one risk factor, only 12% would require confirmatory spirometry using this criterion. CONCLUSIONS: Adding PEF measurement to a screening questionnaire may rule out severe to very severe COPD without the need for pre- and post-BD spirometry testing. Confirmation is needed from a study using inexpensive PEF meters or pocket spirometers with a staged screening protocol.

Long-term follow-up of a cohort of children with alpha-1-antitrypsin deficiency.

We assessed lung function, liver function, and smoking attitudes and behavior in 22 adolescents with homozygous alpha 1-antitrypsin deficiency whose condition had been detected through neonatal screening in the early 1970s. All subjects had normal lung volumes, expiratory flow rates, and diffusing capacity except for two siblings with mild asthma whose values reverted to the normal range after administration of an inhaled bronchodilator. Liver function was normal in all subjects with the exception of one boy who had an isolated elevation of alkaline phosphatase activity. Smoking attitudes, as determined by questionnaire, did not differ from those of 130 control subjects, but smoking initiation rates were significantly lower (p = 0.02). We believe that the issue of neonatal screening for alpha 1-antitrypsin deficiency should be reexamined because augmentation therapy for adults with emphysema is now available, and screening followed by family-based smoking intervention may lead to a nonsmoking life-style. The latter is especially important because the current weight of epidemiologic evidence strongly suggests that in nonsmokers with this condition, severe emphysema may never develop or, if it does, it will do so at a much later age than in smokers.