High Use of SABAs is Associated with Higher Exacerbation Rate in Dutch Patients with Asthma

Figures & data

Figure 1 SABA usage in the last week (n=736).

Notes: Survey question: “Thinking about the last week. How many times have you used your reliever inhaler? (This is usually a blue colour)”; The reported percentages are rounded to whole numbers.

Table 1 Demographics and Characteristics as Reported by Respondents According to SABA Use (n=736)

	Respondents with <3 SABA (Low-SABA Users) in the Last Week 39.9% (n=294)	Respondents with ≥3 SABA (High-SABA Users) in the Last Week 60.1% (n=442)	P values^a
Gender, % (n)
Female	75.2% (n=221)	72.2% (n=319)	P=0.395
Male	24.8% (n=73)	27.8% (n=123)
Age, years, median [IQR]	34 [25–42]	38 [29–45]	P<0.001
Age range, years, % (n)
18–25	25.5% (n=75)	17.0% (n=75)	P=0.003
26–40	42.5% (n=125)	40.3% (n=178)
41–50	32.0% (n=94)	42.8% (n=189)
Year since asthma diagnosis, % (n)
Data available	83.3% (n=245)	88.5% (n=391)
1 or less	5.7% (n=14)	7.2%(n=28)	P=0.478
2–5	12.7% (n=31)	10.5% (n=41)
6–10	15.9% (n=39)	12.8% (n=50)
11 or more	65.7% (n=161)	69.6% (n=272)
Current smokers, % (n)	25.9% (n=76)	24.0% (n=106)	P=0.601
Co-morbidities*, % (n)
Diabetes	3.1% (n=9)	7.0% (n=31)	P=0.020
Depression	14.6% (n=43)	15.4% (n=68)	P=0.834
Heart disease	1.4% (n=4)	2.3% (n=10)	P=0.425
High blood pressure	7.5% (n=22)	14.0% (n=62)	P=0.006
Rheumatoid arthritis	4.1% (n=12)	8.6% (n=38)	P=0.017
Cancer	0.7% (n=2)	1.4% (n=6)	P=0.487
Comorbidity Index
0	74.8% (n=220)	63.8% (n=282)	P=0.002
1	20.7% (n=61)	24.9% (n=110)
2	2.7% (n=8)	9.3% (n=41)
3	1.0% (n=3)	1.6% (n=7)
4	0.7% (n=2)	0.5% (n=2)
5	0.0% (n=0)	0.0% (n=0)
6	0.0% (n=0)	0.0% (n=0)
7	0.0% (n=0)	0.0% (n=0)
8	0.0% (n=0)	0.0% (n=0)
Treatment type^#, % (n)
Reliever (SABA)	75.9% (n=223)	73.5%(n=325)	P=0.723
Preventer (ICS)	40.5% (n=119)	47.1% (n=208)	P=0.082
Combination inhaler (ICS/LABA)	25.2% (n=74)	34.4%(n=152)	P=0.009
Oral treatment	6.5% (n=19)	20.1% (n=89)	P<0.001
Other asthma medication	5.4% (n=16)	14.5% (n=64)	P<0.001

Notes: *Self-reported as having been diagnosed by a doctor; ^ap values are two sided for the difference between <3 SABA and ≥3 SABA groups (significant differences are marked bold); ^#Which of the following treatments do you currently take to help manage your asthma? - multiple answers possible.

Abbreviations: SABA, short-acting beta2 agonist; COPD, chronic obstructive pulmonary disease; ICS, inhaled corticosteroids; LABA, long acting beta2 agonist.

Figure 2 Indicators of exacerbations (n=736), according to SABA use (<3 times or ≥3 times/week).

Notes: <3 SABA (Low-SABA users) n=294; ≥ 3 SABA (High-SABA users) n=442; P values are two sided; The reported percentages are rounded to whole numbers. •Significant difference p<0.001.

Figure 3 Indicators of asthma symptoms (n=736), according to SABA use (<3 or ≥3 times/week).

Notes: <3 SABA (Low-SABA users) n=294; ≥3 SABA (High-SABA users) n=442; P values are two sided, (A) p=0.895, (B) p=0.265, (C) p= 0.109; The reported percentages are rounded to whole numbers.

Table 2 Relation Between Moderate (A)/Severe (B) Exacerbations and SABA Use Adjusted for Confounders (n=736)

Predictors	Coefficients (SE)	p-value	OR	95% CI for OR
				Lower	Upper
A: Relation between moderate exacerbations and SABA use adjusted for confounders
SABA use (0= low SABA users; 1= high SABA user)	0.600 (0.160)	P<0.001	1.822	1.332	2.491
Age	−0.002 (0.008)	0.777	0.998	0.981	1.014
Gender (0= male; 1= female)	−0.511 (0.184)	0.005	0.600	0.418	0.860
Using ICS containing treatment (0= not using ICS; 1= using ICS)	0.037 (0.176)	0.833	1.038	0.735	1.466
Smoking status (0= no smoker; 1= smoker)	0.234 (0.182)	0.200	1.264	0.884	1.807
Comorbidity Index	0.432 (0.123)	P<0.001	1.541	1.211	1.961
B: Relation between severe exacerbations and SABA use adjusted for confounders
SABA use (0= low SABA users; 1= high SABA user)	1.485 (0.342)	P<0.001	4.417	2.260	8.663
Gender (0= male; 1= female)	−1.291 (0.262)	P<0.001	0.275	0.165	0.460
Using ICS containing treatment (0= not using ICS; 1= using ICS)	−0.041 (0.280)	0.885	0.960	0.554	1.664
Comorbidity Index	0.582 (0.141)	P<0.001	1.789	1.357	2.360

Notes: The confounders comorbidities, smoking status and number of years since asthma diagnosis were added to the models based on their relation (p<0.20) with the dependent or independent variable. The variable age was not added to model B since the linearity assumption was not met.

Abbreviations: SABA, Short-acting Beta-agonist; SE, standard error; OR, Odds ratio; CI, Confidence interval; ICS, Inhaled corticosteroids.