The mean daily ICS dose at baseline also was evaluated and was included in the adjusted models if significant. The dependent variable used for the analysis of both subgroups was increasing use, resulting in the determination of odds ratios (ORs) for increasing use relative to remaining in the low-use group over the 3 years in controlled users, and for increasing use relative to decreasing use in uncontrolled users. All variables significant in univariate analyses at a level of a = 0.10 were included in the multiple regression models. Model fit was assessed using —2 Log Likelihood. Crude and adjusted ORs and 95% confidence intervals (CIs) are reported for each variable.
A total of 78,758 individual patients in Pharmacare plans C and E filled at least one prescription for a SA P-agonist in any of the 3 years (1996, 43,277 patients; 1997, 41,790 patients; and 1998, 33,781 patients) [Table 1]. A total of 618,519 prescriptions for asthma medications (ie, SA P-agonists, ICS agents, ipratropium bromide, theophylline, long-acting P-agonists, chromoglycans, and nedocromil) were filled or refilled over this time period. The majority of the population was composed of women (62.2%; p < 0.001) and were receiving social assistance (ie, Pharmacare plan C; 56%; p < 0.001). The number of patients included in the entire cohort accounts for approximately 17% of the all patients covered by both Pharmacare plans C and E in 1996. The average (± SD) age was 32.3 ± 11.4 years. Patients who were on plan E were significantly older than were patients on plan C (33.3 vs 31.6 years, respectively; p < 0.0001), and women were significantly older than men (32.9 vs 31.5 years, respectively; p < 0.0001).). Of the 10,686 patients who received at least one SA P-agonist prescription each year, 1,408 (17%) were between 13 and 17 years of age, and 3,463 (32.4%) were between 18 and 35 years of age.
Table 1—Annual Number of Canisters of SA fi-Agonist Received
Canisters per Year
|5-12 Canisters per Year||13-20 Canisters per Year||> 20 Canisters per Year|
|1996||35,251 (81.5)||4,999(11.6)||1,804 (4.2)||1,223 (2.8)||43,277|
|1997||33,895 (81.1)||4,981 (11.9)||1,689 (4.0)||1,225 (2.9)||41,790|
|1998||27,515 (81.4)||4,114(12.2)||1,263 (3.7)||889 (2.6)||33,781|