Objective: To assess changes in the severity of physician-diagnosed asthma between 1983 and 1988.
Design: Cross-sectional studies examining the frequency of markers of asthma severity: hospitalizations, ICU admissions, hospital emergency department visits, multiple physician contacts, and referrals to specialists in patients aged 0 to 14 years, 14 to 34 years, and > or = 35 years separately.
Setting: Physicians' claims data from the universal Provincial Health Insurance Plan for fiscal years 1983 and 1988.
Patients: All patients with the diagnosis of asthma, bronchitis, and COPD identified from the Manitoba Health database.
Measurements: The markers of severity were related to the prevalence of patients seeing a physician and receiving a diagnostic label of asthma, COPD, or bronchitis.
Results: The number of patients with physician-diagnosed asthma increased by 36.4% over the 5 years. In 1983, 11% of asthmatics were hospitalized during the year and 8% were hospitalized in 1988 (-2.5%; 95% confidence interval [CI], -3.2 to -1.8%). During both years, about 75% of the patients hospitalized were in hospital once only. Mean and median duration of hospital stay declined. The percentage of asthmatics seen in the hospital emergency departments declined slightly in all age groups, the total being 21% in 1983 and 18% in 1988 (-3.5%; 95% CI, -4.5 to -2.5%). About one third of the patients with asthma were seen only once by a physician during both of the years examined, 43 to 45% of them being seen on three or more occasions during both years. Referrals to specialists for all asthmatics increased from 12 to 14% (1.9%; 95% CI, 1.0 to 2.8%) from 1983 to 1988. This was almost entirely due to an increase from 11 to 16% (5.1%; 95% CI, 4.0 to 6.2%) in the youngest age group, an increase not accompanied by an increase in any other marker of severity. Changes in asthma severity were similar to changes in the severity in patients with bronchitis and COPD.
Conclusion: No increase in severity of asthma was seen between 1983 and 1988, but the prevalence of the diagnostic label of asthma increased substantially.