What is the Best Way to Diagnose Possible Asthma Patients with Negative Bronchodilator Reversibility Tests?

Figures & data

Figure 1 Material and method: Demographic characteristics, physical examinations, pulmonary function tests, asthma control tests, quality of life questionnaires were performed at the first application of the participants (Visit 0) who consented to participate in the study. PEF meters were provided to each of them, and their usage was explained. A chart was given to the participants for follow-up standardization. They were asked to perform PEF follow-up for 2 weeks. After 2 weeks, the participants were given mBPT appointments (Visit 1). According to the patients whose results were evaluated, treatment was started according to the recommendations of the GINA guideline. They were called for control after 1 month (Visit 2). Physical examination, pulmonary function tests, quality of life questionnaires, and asthma control tests were renewed and recorded.

Table 1 Demographic and Clinical Features of the Study Group

	Asthma (n=30)	Non-Specific Respiratory Symptoms (n=20)	Total (n=50)	p
Gender F, n(%)	20 (66.6)	14 (70)	34 (68)	0.804
Dr. diagnosed asthma	17 (%56.7)	11 (%55)	28 (%56)	0.907
BD treatment history	17 (%56.7)	11 (%55)	28 (%56)	0.907
Family history	10 (%33.3)	6 (%30)	16 (%32)	0.804
Comorbidity	16 (%53.3)	10 (%50)	26 (%52)	0.817
Atopy	21 (%70)	10 (%50)	31 (%62)	0.153
Age	32.73 (10.04)	33.25 (10.87)	32.94 (10.27)	0.864
BMI	26.6 (17–42)	26.45 (17–38.5)	26.45 (17–42)	0.692
Blood EOS level	200 (75–797)	200 (59–800)	200 (59–800)	0.546

Abbreviations: BMI, body mass index; BD, bronchodilator; EOS, eosinophil.

Table 2 Clinical Features of the Study Group

	Asthma (n=30)	Non-Specific Respiratory Symptoms (n=20)	Total (n=50)	p
Cough, n(%)	12 (60)	12 (60)	35 (70)	0.208
Wheezing, n(%)	19 (63.3)	6 (30)	25 (50)	0.021
Shortness of breath, n(%)	23 (76.7)	17 (85)	40 (80)	0.720
Tightness in the chest, n(%)	6 (20)	3 (15)	9 (18)	0.724
Total number of symptoms	2 (1–4)	2 (1–4)	2 (1–4)	0.068
Symptom duration (months)	11 (1–156)	15 (0.5–72)	11 (0.5–156)	0.766
Activity restriction, n(%)	10 (33.3)	2 (10)	12 (24)	0.050
Nocturnal symptom, n(%)	18 (60)	9 (45)	27 (54)	0.297
Total symptom weight score	2 (0–4)	1 (0–3)	2 (0–4)	0.028

Notes: Total symptom weight score: The number of daytime symptoms (0 = <2 per month, 1 = 2 times a month, 2 = >2 per week) + activity restriction + night symptom (0–4) were calculated by scoring.

Table 3 Basal Spirometry and Survey Data of the Study Group (Visit 0)

	Asthma (n=30)	Non-Specific Respiratory Symptoms (n=20)	Total (n=50)	p
FEV1, mean (SD)	91.13 (14.65)	96.75 (11.21)	93.38 (13.55)	0.153
FVC, mean (SD)	91.93 (14.73)	96.1 (10.20)	93.6 (13.16)	0.277
FEV1/FVC, med (min-max)	83.5 (77–98)	87 (79–92)	85 (77–98)	0.393
PEF, mean (SD)	86.23 (12.15)	88.55 (16.39)	87.16 (13.89)	0.569
FEF25-75, mean (SD)	81.90 (19.75)	93.75 (21.43)	86.64 (21.06)	0.050
Basal ACT, med (min-max)	14 (6–20)	13 (6–20)	14 (6–20)	0.510
Basal AQLQ, mean (SD)	148.37 (41.5)	151.65 (39.95)	149.68 (40.5)	0.782
Basal MCS, SF-36	155.9 (61–213)	167.9 (97.6–206)	165.9 (61–213)	0.898
Basal PCS, SF-36	269.5 (86.7)	286.88 (67.63)	276.45 (73.95)	0.454

Note: SF-36 test components.

Abbreviations: MCS, Mental Component Score; PCS, Physical Component Score; ACT, Asthma Control Test; AQLQ, Asthma Quality of Life Questionnaire; SD, Standart Deviation.

Table 4 Multivariate Linear Regression Analysis That Examines Various Parameters to Predict Asthma Diagnosis

	B Co-Efficient	Beta Co-Efficient	Standard Error	p	95% Confidence Interval
Wheezing	0.242	0.247	0.172	0.16	−0.105–0.589
Activity restriction	0.084	0.073	0.199	0.67	−0.318–0.485
Total symptom weight score	0.075	0.181	0.075	0.32	−0.076–0.226
FEF25-75	−0.006	−0.264	0.003	0.05	−0.013–0.000

Notes: Total symptom weight score: The number of daytime symptoms (0 = <2 per month, 1 = 2 times a month, 2 = >2 per week) + activity restriction + night symptom (0–4) were calculated by scoring.

Table 5 Correlation Rates Between Patients with BPT Positivity and Different Cut-off Values of PEF Variability

PEF Positivity in Those with mBPT(+)			Correlation of PEF Variability with mBPT
PEF variability	PEF (+)/BPT(+)	%	PEF variability	r	p
>10%	26/26	100	>10%	0.307	0.03
>15%	23/26	88.5	>15%	0.530	<0.001
≥20%	16/26	61.5	≥20%	0.328	0.09
PEF variability	Sensitivity		Specificity		CI
≥20%	61.5%		83.3%		0.58–0.86
>15%	88.5%		62.5%		0.61–0.89
>10%	100%		16.7%		0.42–0.74

Notes: When BPT positivity is accepted as the gold standard in the diagnosis of asthma and Sensitivity and Specificity are evaluated for 3 different threshold values of PEF variability.

Abbreviations: PEF, Peak expiratory flow; mBPT, Methacolin bronchial provocation test; CI, Confidence interval.

Figure 2 Results; BPT alone was positive in 10 of 30 asthma cases. Both mBPT positivity and PEF variability were positive in 16 cases. Only four out of 30 patients were diagnosed with asthma based on positive PEF variability. 20 patients were evaluated as non-specific respiratory symptoms. No treatment was given. At the end of the 1st month, 17 of the 30 treated patients attended visit 2. 13 patients did not attend visit 2. Treatment response of 17 patients was evaluated.

Table 6 1st Month Control Results of Those Who Started Treatment with Asthma Diagnosis (n=17)

	Visit0	Visit2	p
FEV1, mean (SD)	91.1 (14.6)	97.3 (16.9)	0.043
FVC, mean (SD)	91.9 (14.7)	97.9 (18.9)	0.021
PEF, mean (SD)	86.2 (12.1)	100.9 (10.2)	0.001
ACT, med (min-max)	14 (6–20)	22 (13–25)	0.001
SF-36 Physical function, med (min-max)	80 (20–100)	75 (40–100)	0.028
SF-36 PCS, mean (SD)	269.5 (86.6)	299.8 (61.6)	0.039
AQLQ, mean (SD)	148.3 (41.5)	162.1 (31.4)	0.028
Symptoms, mean SD	29.5 (8.9)	34 (6.4)	0.049
Activity restriction, mean SD	25.7 (6.1)	27.3 (5.5)	0.024

Note: SF-36 test components.

Abbreviations: MCS, Mental Component Score; PCS, Physical Component Score; ACT, Asthma Control Test; AQLQ, Asthma Quality of Life Questionnaire; SD, Standard Deviation.