'Wasif' Score for the Oasys program

The following is the abstract for the research that led to the 'Wasif' score. The link to the paper is at the bottom

Introduction and Aims

Serial peak expiratory flow (PEF) records have been recommended as a first line investigation in workers suspected as having occupational asthma. It is unclear, however, to what extent they can differentiate between workers with occupational asthma and healthy workers exposed to irritant agents, and which index of PEF variability is best at doing so. Methods: Indices of PEF variability were compared in three groups of subjects. (1) Forty healthy grain exposed farmers and dockers. (2) Forty two consecutive subjects with independently confirmed occupational asthma. (3) Forty eight non-occupational asthmatics.

Results

The index of PEF variability that best separated the occupational asthmatic workers from the others was the difference in mean PEF between day-interpreted rest and work periods. The upper 95% confidence limit of this index for the grain workers was 2.8% of predicted PEF (16 L/min), for non-occupational asthmatics 3.3% predicted PEF (15 L/min). Sensitivity for diagnosing occupational asthma using this index was 70%. Only 40% of workers with confirmed occupational asthma had a PEF diurnal variability >17% of predicted, the upper limit for grain workers. An increase in diurnal variation on work days of >7% (the upper 95% limit for non-occupational asthmatics) had a sensitivity of only 27% for the diagnosis of occupational asthma. The difference between maximum PEF on work days and minimum PEF on rest days was poor at separating occupational asthmatic workers from those with non-occupational asthma.

Conclusion

Difference in mean PEF between day-interpreted work and rest days is the best simple index for differentiating subjects with occupational asthma from those with non-occupational asthma or irritant exposed healthy subjects.

References

	Anees W, Blainey D, Moore VC, Robertson K, Burge PS, Differentiating occupational asthmatics from non-occupational asthmatics and irritant-exposed workers, Occup Med, 2011;61:191-195,

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