Table 3

Age-adjusted incidence rate ratios (IRR) of exacerbations, in the risk period compared with stable periods, after an inhaler switch (brand-to-brand, generic-to-generic or generic-to-brand)

Exacerbations in risk periodExacerbations in control periodIRR95% CI
3-month risk period35233622980 0.79 0.71 to 0.88
Variable association may be modified by Patients
Exacerbations in risk period Exacerbations in control period IRR 95%  CI P value
 COPD625555340.640.48 to 0.85
 Asthma289830724460.820.73 to 0.93
 Male156815513380.750.63 to 0.89
 Female195520716420.820.71 to 0.95
Medication class switched0.20
 ICS180120015220.870.75 to 1.00
 LABA195181700.730.45 to 1.20
 LABA-ICS1024978600.720.58 to 0.89
 LAMA503474280.700.52 to 0.95
Switch: generic/ branded0.35
 Generic to brand27424720710.780.68 to 0.89
 Generic to generic2433232360.610.39 to 0.94
 Brand to brand816926730.870.70 to 1.09
Switch between MDI and DPI0.11
 Yes918767860.640.50 to 0.81
 No161717513540.830.71 to 0.97
Inhaler check in prior year0.89
 Yes1397342760.800.56 to 1.13
 No212632827040.790.70 to 0.88
  • COPD, chronic obstructive pulmonary disease;DPI, dry powdered inhaler; ICS, inhaled corticosteroid; LABA, long-acting beta agonist; LAMA, long-acting muscarinic antagonist; MDI, metered-dose inhaler.