Audit of quality of diagnostic procedures for occupational asthma

Previous studies have reported deficiencies in the quality of the diagnosis of occupational asthma. A low quality of diagnostic procedures means that the occupational cause of asthma is less likely to be revealed.

To assess the current quality of the diagnosis of occupational asthma before referral to a specialist occupational medicine centre.

The quality of diagnostic procedures was assessed by reviewing the files of 150 patients who were referred to the Finnish Institute of Occupational Health in 2003 with a suspicion of an occupational cause of their asthma. The quality indicators used were assessment of workplace exposures, spirometric studies, bronchodilator response, serial workplace measurements of peak expiratory flow (PEF) and the time since first symptoms to the final diagnosis. For each indicator, criteria to differentiate between sufficient and insufficient care were developed.

Exposure assessments, spirometric studies and bronchodilator responses were performed in 92, 87 and 79% of cases in the total study group, respectively. Workplace measurements of PEF had been performed in 51% of the cases, and the quality of measurements was sufficient in 52%. Workplace exposures had been assessed significantly more often in occupational health care than in other health care units. The median time from the beginning of symptoms to the final diagnosis was 3.2 years.

Although the diagnostic procedures were mostly of sufficient quality, the performance of serial measurements of PEF at the workplace and the time to diagnosis should be substantially improved.