Occupational asthma (OA) refers to asthma caused by workplace-specific substances. A longer duration of symptoms while continuing to be exposed has been associated with a worse prognosis. Evidence suggests a significant period of time exists between symptom onset and diagnosis of OA, the reasons for which have not been investigated. The purpose of this study was to examine whether primary health care and/or socio-economic factors account for delays in Ontario.
Two hundred and forty-seven (247) chart reviews were undertaken of patients referred to the University Health Network Asthma Centre for evaluation of OA, with clinic visits from 1997-2002. Forty-two (42) patients fulfilling objective OA criteria were administered a structured telephone interview to examine the chronology and nature of health care consultation and reasons for possible delay in diagnosis.
The mean time to diagnosis was 4.9 years (3.4 years excluding 4 outliers). On average, patients waited 7.4 months before discussing the work-relation of symptoms with a physician. Main self-reported reasons for delay were lack of enquiry about work relatedness by the primary care physician (41%) and fear of losing work time (37%). Reported increases in time during secondary care were related to difficulties associated with completion of investigations (35%). Lower education level (p = 0.04) and household income (p = 0.03) were significantly associated with an increased time to diagnosis.
Physicians who assess working adults with asthma need to ask pertinent work-related questions when taking a history in order to initiate timely investigations and referral. Socio-economic factors are also associated barriers to early diagnosis of occupational asthma.