Estimating Inhaled Corticosteroid Exposure from Short-Acting β₂-Agonist–Inhaled Corticosteroid Rescue

Figures & data

Figure 1 Observed ICS exposure and projected additional as-needed ICS exposure if each SABA inhalation contained 80 μg budesonide, relative to maximum FDA-approved doses, by maintenance group.

Notes: Percentage values in burgundy indicate the percentage of FDA-approved maximum daily ICS dose reached with observed ICS maintenance therapy; percentage values in green indicate the percentage of FDA-approved maximum daily ICS dose reached with observed ICS maintenance therapy plus projected additional as-needed ICS exposure if each SABA inhalation contained 80 μg budesonide. Data can also be seen in Table 1.

Abbreviations: BUD, budesonide; DPI, dry powder inhaler; FDA, Food and Drug Administration; HFA, hydrofluoroalkane; ICS, inhaled corticosteroid; LABA, long-actingβ₂-agonist; LAMA, long-acting muscarinic antagonist; SABA, short-acting β₂-agonist.

Table 1 Estimated Total ICS Exposure from Maintenance Plus As-Needed SABA-ICS Relative to Observed SCS Exposure

	SABA Only (n=362,861)	Low-Dose ICS (n=44,385)	Medium/High-Dose ICS (n=35,893)	Low-Dose ICS-LABA (n=23,989)	Medium-Dose ICS-LABA (n=65,081)	High-Dose ICS-LABA (n=43,041)	ICS-LABA-LAMA (n=2144)
Daily exposure
Observed ICS maintenance dose (µg/day), mean±SD^a	0	91±56	153±142	79±54	163±120	213±201	271±234
SABA use
Annual SABA fills
Mean±SD	2.2±2.2	3.1±2.8	3.6±3.8	2.8±2.7	3.3±3.2	3.9±3.8	4.9±4.8
Median (IQR)	1.0 (0.7, 2.7)	2.0 (1.2, 3.9)	2.0 (1.0, 4.3)	2.0 (1.0, 3.5)	2.0 (1.1, 4.1)	3.0 (1.3, 4.8)	3.0 (1.7, 6.0)
Inhalations/day^b
Mean±SD	1.2±1.2	1.7±1.5	2.0±2.1	1.5±1.5	1.8±1.8	2.1±2.1	2.7±2.6
Median (IQR)	0.5 (0.4, 1.5)	1.1 (0.7, 2.2)	1.1 (0.6, 2.4)	1.1 (0.5, 1.8)	1.1 (0.6, 2.2)	1.6 (0.7, 2.6)	1.6 (1.0, 3.3)
Projected additional ICS exposure (µg/day) if each SABA inhalation contained 80 µg BUD^c (50 µg FP equivalent), mean±SD	60±60	85±75	100±105	75±75	90±90	105±105	135±130
Estimated total ICS exposure from maintenance + as-needed ICS (µg/day), mean	0+60=60	91+85=176	153+100=253	79+75=154	163+90=253	213+105=318	271+135=406
Annual exposure
Annual total estimated ICS exposure (mg)^a, mean	22	64	92	56	92	116	148
Patients with any SCS exposure, n (%)	187,731 (51.7)	15,298 (34.5)	13,127 (36.6)	7558 (31.5)	27,011 (41.5)	22,327 (51.9)	1206 (56.3)
Annual observed SCS exposure among patients with any SCS exposure (mg), mean±SD^d	451±1214	555±1138	574±1334	542±1438	590±1365	763±1606	1088±2148
Annual observed SCS relative to estimated ICS exposure	21-fold	9-fold	6-fold	10-fold	6-fold	7-fold	7-fold

Notes: ^aInhaled corticosteroid dose/day in µg of fluticasone propionate equivalents; ^bcalculated by multiplying annual SABA fills by 200 (all SABA canisters approved in the US contain 200 inhalations) then dividing by 365; ^cscaled based on budesonide 80 µg equating to 50 µg fluticasone propionate, as per GINA 2021; ^dcumulative annual systemic corticosteroid exposure in mg of prednisone equivalents.

Abbreviations: BUD, budesonide; FP, fluticasone propionate; GINA, Global Initiative for Asthma; ICS, inhaled corticosteroid; LABA, long-acting β₂-agonist; LAMA, long-acting muscarinic antagonist; SABA, short-acting β₂-agonist; SCS, systemic corticosteroid; SD, standard deviation.