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Table 2 Interrupted time series segmented regression analysis with control group of inhaled corticosteroid and long-acting β2-agonist combinations (ICS-LABA)

From: Impact of a change of bronchodilator medications in a hospital drug formulary on intra- and out-of-hospital drug prescriptions: interrupted time series design with comparison group

 Pre-intervention trendPost-intervention
Immediate impact of the formulary changeChange in trend after the formulary change
 Coefficient95% confidence intervalCoefficient95% confidence intervalCoefficient95% confidence interval
DDD/100 stays-day
 Total ICS-LABA− 0.464− 2.117 to 1.1883.344− 10.312 to 17.0020.317− 1.359 to 1993
 Formoterol/budesonidea0.012− 1.438 to 1.46415.830*3835 to 27,825− 0.200− 1.672 to 1,272
 Salmeterol/fluticasoneb− 1.043− 2.483 to 0.396− 7.792*− 15.113 to − 0.4711.075− 0.37 to 2.521
Inpatient expenditure per DDD
 Total ICS-LABA− 0.003− 0.119 to − 0.113− 0.953*− 1.733 to − 0.1740.009− 0.108 to 0.127
DDD/TID
 Total ICS-LABA− 0.405− 1.046 to 0.2350.994− 1.484 to 3.4740.348− 0.290 to 0.986
 Formoterol/budesonide0.066− 0.102 to 0.235− 0.015− 0.820 to 0.790− 0.068− 0.238 to 0.101
 Salmeterol/fluticasone− 0.039− 0.194 to 0.115− 0.143− 0.991 to 0.7040.034− 0.121 to 0.190
 Formoterol/beclometasone− 0.008− 0.141 to 0.123− 0.182− 0.817 to 0.453− 0.030− 0.164 to 0.102
 Formoterol/fluticasone0.006− 0.021 to 0.0330.107− 0.103 to 0.3190.001− 0.026 to 0.029
 Vilanterol/fluticasone0.008− 0.01 to 0.027− 0.023− 0.154 to 0.107− 0.017− 0.037 to 0.002
Outpatient expenditure per DDD
 Total ICS-LABA− 0.405− 1.046 to 0.2350.994− 1.484 to 3.4740.348− 0.290 to 0.986
  1. aThe only ICS-LABA that remained in the intervention hospital drug formulary after the intervention
  2. bAfter the intervention, this ICS-LABA was removed from the intervention hospital drug formulary (not at the control hospital)
  3. *p < 0.05