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Table 3 Analysis of β2-agonist effects on FEV1 decline in categories of placebo-test FEV1 declines

From: Many continuous variables should be analyzed using the relative scale: a case study of β2-agonists for preventing exercise-induced bronchoconstriction

FEV1 decline after placebo (range)Mean FEV1 decline after placeboAbsolute effect on FEV1 decline (pp) (95% CI)Relative effect (95% CI)N
10–19%15.5%15.2 (10.2–20.3)0.99 (0.79–1.24)33
20–29%24.7%23.6 (17.7–29.9)0.92 (0.74–1.14)29
30–39%34.5%33.0 (25.0–40.9)0.95 (0.78–1.15)34
40–49%44.5%39.7 (30.6–49.3)0.83 (0.69–1.00)29
50–83%59.9%44.3 (34.8–54.6)0.71 (0.60–0.84)34
  1. Footnote: this table is restricted to 159 participants who had exercise-induced FEV1 decline of ≥10% in the placebo test. The 95% CI for the relative effect was calculated with the approach described in [5], see Additional file 1. Abbreviations: pp., percentage points