Table 4

Adjusted rate ratios and rate reductions of asthma hospitalisation for regular inhaled corticosteroid use relative to both irregular and non-use during the year before the index date, according to follow up time, for the full and hospitalised cohorts

CasesControlsAdjusted* rate ratio (95% CI)Rate reduction (%)
*In addition to matching, rate ratios are further adjusted for the number of dispensed prescriptions of theophylline, nebulised and oral β agonists, oral corticosteroids and the number of canisters of inhaled β agonists, all dispensed during the year before the index date, as well as the number of asthma hospitalisations during the year before cohort entry, age, and sex.
**Combining the full and hospitalised cohort.
Full cohort
Follow up: overall3894353990.69 (0.57 to 0.83)31%
    <4 years2388220800.70 (0.54 to 0.92)30%
    >4 years1506133190.65 (0.49 to 0.89)35%
Hospitalised cohort
Follow up: overall1886136360.61 (0.50 to 0.75)39%
    <4 years105278790.58 (0.43 to 0.77)42%
    >4 years83457570.65 (0.48 to 0.89)35%
Combined cohorts**
Follow up: overall5780490350.66 (0.58 to 0.76)34%
    <4 years3440299490.65 (0.53 to 0.79)35%
    >4 years2340190860.66 (0.54 to 0.81)34%