Abstract
Background: Serial measurements of peak expiratory flow (PEF) are recommended for confirming a diagnosis of occupational asthma but there is a tradeoff between accepting only good quality measurements with reduced data quantity and accepting all measurements irrespective of quality. We have investigated the effect of systematically reducing quality or quantity on the diagnostic sensitivity and specificity using the Oasys system.
Methods: Serial PEF measurements from 36 specific inhalation challenge positive occupational asthmatics and 44 non-occupational asthmatics were used. Records contained 4 weeks of ≥ 4 PEF readings/day for 75% of days. Data was corrupted in 2 ways: 1) Each PEF was randomly changed up to +50L/min or -50L/min from the original in increments of 10 L/min. Records were randomised 3 times 2) Independently, the number of readings per day were reduced randomly from ≥7 readings per day to 2 readings per day. The sensitivity and specificity of the Oasys score and area between curves (ABC) score were compared.
Results: Altering PEF readings or reducing the number of readings had little effect on sensitivity and specificity. Table 1 shows the results
Conclusion: Oasys analysis is robust despite decreasing data quality and quantity.
- Copyright ©the authors 2016