How many times per day should peak expiratory flow rates be assessed when investigating occupational asthma?

J L Malo, J Côté, A Cartier, L P Boulet, J L'Archevêque, M Chan-Yeung

Department of Chest Medicine, Sacré-Coeur Hospital, West Gouin, Montreal, Canada.

BACKGROUND--Serial peak expiratory flow rate (PEF) recording has been advocated as a sensitive and specific means of confirming work related asthma. The optimum number of recordings per day to achieve the best between-reader and within-reader reproducibility and sensitivity/specificity ratio compared with the final diagnosis determined by specific inhalation challenges is unknown. METHODS--PEF recording was carried out every two hours in 74 subjects referred for possible occupational asthma. Specific inhalation challenges performed in a hospital laboratory or at the workplace (positive in 33 subjects and negative in 41) were considered the gold standard. The duration of monitoring at work and away from work was at least two weeks each. Graphs of PEF recordings were generated in four different ways: every two hours, four times/day, three times/day, and every morning and evening. The graphs were assessed by three readers in three different centres in a blind manner. Furthermore, one third of each type of graph was read blind by the same reader one week after the initial interpretation. RESULTS--Agreement between the three readers was a little more frequent (82%) in the case of the every two hour readings than for the other types of readings (70% v 77%). Agreement between at least two of the three readers occurred in 73% of positive challenges (sensitivity) and in 78% of negative challenges (specificity) for every two hour readings. The figures varied from 61% to 70% for positive challenges and from 78% to 88% for negative challenges for the other types of readings. Within-subject reproducibility from one reading to the next (one week apart) was excellent (83% to 100%). CONCLUSIONS--Recording PEF every two hours results in a slightly more satisfactory agreement between readers and in concordance in terms of sensitivity/specificity than less frequent PEF readings, although the four times a day assessment is almost as satisfactory.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• Moore, V. C., Jaakkola, M. S., Burge, C. B. S. G., Pantin, C. F., Robertson, A. S., Vellore, A. D., Burge, P. S. (2009). PEF analysis requiring shorter records for occupational asthma diagnosis. Occup Med (Lond) 59: 413-417 [Abstract] [Full Text]  
• Tarlo, S. M., Balmes, J., Balkissoon, R., Beach, J., Beckett, W., Bernstein, D., Blanc, P. D., Brooks, S. M., Cowl, C. T., Daroowalla, F., Harber, P., Lemiere, C., Liss, G. M., Pacheco, K. A., Redlich, C. A., Rowe, B., Heitzer, J. (2008). Diagnosis and Management of Work-Related Asthma: American College of Chest Physicians Consensus Statement. Chest 134: 1S-41S [Abstract] [Full Text]  
• Bolen, A. R, Henneberger, P. K, Liang, X., Sama, S. R, Preusse, P. A, Rosiello, R. A, Milton, D. K (2007). The validation of work-related self-reported asthma exacerbation. Occup. Environ. Med. 64: 343-348 [Abstract] [Full Text]  
• Fishwick, D., Bradshaw, L., Henson, M., Stenton, C., Hendrick, D., Burge, S., Niven, R., Warburton, C., Rogers, T., Rawbone, R., Cullinan, P., Barber, C., Pickering, T., Williams, N., Ayres, J., Curran, A. D (2007). Occupational asthma: an assessment of diagnostic agreement between physicians. Occup. Environ. Med. 64: 185-190 [Abstract] [Full Text]  
• Nicholson, P J, Cullinan, P, Newman Taylor, A J, Burge, P S, Boyle, C (2005). Evidence based guidelines for the prevention, identification, and management of occupational asthma. Occup. Environ. Med. 62: 290-299 [Abstract] [Full Text]  
• Anees, W., Gannon, P.F., Huggins, V., Pantin, C.F.A., Burge, P.S. (2004). Effect of peak expiratory flow data quantity on diagnostic sensitivity and specificity in occupational asthma. Eur Respir J 23: 730-734 [Abstract] [Full Text]  
• Tarlo, S. M., Liss, G. (2003). An Oasys for occupational asthma. CMAJ 169: 189-190 [Full Text]  
• Baldwin, D R, Gannon, P, Bright, P, Newton, D T, Robertson, A, Venables, K, Graneek, B, Barker, R D, Cartier, A, Malo, J-L, Wilsher, M, Pantin, C F A, Burge, P S (2002). Interpretation of occupational peak flow records: level of agreement between expert clinicians and Oasys-2. Thorax 57: 860-864 [Abstract] [Full Text]  
• LEROYER, C., PERFETTI, L., TRUDEAU, C., L'ARCHEVQUE, J., CHAN-YEUNG, M., MALO, J.-L. (1998). Comparison of Serial Monitoring of Peak Expiratory Flow and FEV1 in the Diagnosis of Occupational Asthma. Am. J. Respir. Crit. Care Med. 158: 827-832 [Abstract] [Full Text]  
• Gannon, P F G, Newton, D T, Pantin, C F A, Burge, P S (1998). Effect of the number of peak expiratory flow readings per day on the estimation of diurnal variation. Thorax 53: 790-792 [Abstract] [Full Text]