The Relationship Between Clinical Trial Participation and Inhaler Technique Errors in Asthma and COPD Patients

Figures & data

Figure 1 Checklist of critical steps in pMDI technique.

Table 1 Baseline Characteristics of Study Participants Stratified by Diagnosis

Characteristics	Asthma (N=205)	COPD (N=152)	Total (N=357)	p-value
Age, mean(SD)	45.2(15.8)	62.4(8.0)	52.5(15.6)	<0.001*
Sex
Male, n(%)	58(28.3)	96(63.2)	154(43.1)	<0.001^€
Prior pMDI experience (years), median (IQR)	15(6–26)	6(3–11)	10(5–20)	<0.001^¥
Prior pMDI training
None, n(%)	13(6.3)	19(12.5)	32(9.0)
Doctor, n(%)	165(80.5)	118(77.6)	283(79.2)	0.20^€
Nurse, n(%)	21(10.2)	11(7.2)	32(9.0)
Pharmacist, n(%)	6(2.9)	4(2.6)	10(2.8)
Prior clinical trial participation
None, n(%)	150(73.2)	126(82.9)	276(77.3)	0.09^€
<3 trials, n(%)	34(16.6)	17(11.2)	51(14.3)
≥3 trials, n(%)	21(10.2)	9(5.9)	30(8.4)

Notes: *Independent samples t-test, ^€Pearson chi-square, ^¥Mann–Whitney U-test.

Abbreviations: SD, standard deviation; IQR, interquartile range; pMDI, pressurised metered-dose inhaler.

Table 2 Frequency of Critical Errors in All Participants

Step	Error Frequency (N=357)
Shake the inhaler	15.1%
Complete exhalation	49.6%
Tight seal around the mouthpiece	12%
Coordination between device activation and inhalation	25.2%
Slow, deep inhalation	48.7%
Breath-hold after inhalation	47.3%
Cumulative errors
One or more error(s)	66.7%
Four or more errors	24.9%

Table 3 Multivariate Binomial Logistic Regression Analysis to Evaluate the Determinants of Inadequate Inhaler Technique

Characteristics	Adjusted OR	95% CI	p-value
Age	1.0	0.98–1.01	0.61
Sex
Female	Reference
Male	0.72	0.42–1.2	0.21
Diagnosis
Asthma	Reference
COPD	2.25	1.13–4.47	0.02
Prior pMDI experience	1.01	0.98–1.03	0.66
Prior pMDI training
None	Reference
Nurse	0.26	0.03–2.55	0.25
Doctor	0.08	0.01–0.57	0.01
Pharmacist	0.02	0.01–0.26	0.002
Prior clinical trial participation
None	Reference
<3 trials	0.35	0.19–0.66	0.001
≥3 trials	0.17	0.07–0.42	<0.001

Abbreviations: OR, odds ratio; CI, confidence interval; pMDI, pressurised metered-dose inhaler.

Table 4 Frequency of Critical Errors Stratified by Prior Clinical Trial Participation

Step	None	<3 Trials	≥3 Trials	Total (N=357)	p-value
Shake the inhaler	17%	11.8%	3.3%	15.1%	0.10*
Complete exhalation	54.3%	37.3%	26.7%	49.6%	0.003
Tight seal around mouthpiece	15.2%	0%	3.3%	12%	0.001*
Coordination between device activation and inhalation	28.6%	19.6%	3.3%	25.2%	0.006
Slow, deep inhalation	57.2%	27.5%	6.7%	48.7%	<0.001
Breath-hold after inhalation	54.3%	31.4%	10%	47.3%	<0.001
Cumulative errors
One or more error(s)	74.6%	47.1%	26.7%	66.7%	<0.001
Four or more errors	29%	15.7%	3.3%	24.9%	0.002

Notes: *Fisher’s exact test. Pearson chi-square for all other comparisons.