The role of human rhinovirus in COPD exacerbations in Abu Dhabi: molecular epidemiology and clinical significance

Figures & data

Table 1. Master mix preparation for HRV detection.

Reagent	Volume per reaction
Invitrogen reaction mix x2 (3mM MgSO4)	7.5μl
HRV 8A @ 100µM (final 0.2uM)	0.03μl
HRV 8B @ 100µM (final 0.2uM)	0.03μl
HRV 8C @ 100µM (final 0.4uM)	0.06μl
HRV 8P @ 100µM FAM-BHQ (final 0.2uM), probe
Superscript enzyme mix	0.03μl
MgSO4 @ 50mM (final 4mM)	0.3μl
Nuclease-free water	2.75μl

Table 2. Baseline clinical data for the study participants (N = 78).

Variables	Statistic
Age, M (Range)	57.3 (45 to 77)
Gender, N (%)
Male	46 (59.0%)
Female	32 (41.0%)
Body mass index (BMI), M (±SD)	28.55 (±4.17)
Smoking, N (%)
Current smoker	0 (0.0%)
Previous smoking history	78 (100.0%)
COVID-19 vaccination status, N (%)
Two doses	78 (100.0%)
Severity of airflow limitation
GOLD grade I	4 (5.1%)
GOLD grade II	34 (43.6%)
GOLD grade III	35 (44.9%)
GOLD grade IV	3 (3.8%)
No. of exacerbations during the last year, Median (Range)	3 (2 to 5)
Comorbidities, N (%)
Diabetes mellitus	45 (57.7%)
Cardiovascular disease	50 (64.1%)
Maintenance medication
LAMA	5 (6.4%)
LAMA/LABA	60 (76.9%)
ICS/LABA	1 (1.3%)
ICS/LABA/LAMA	12 (15.4%)
Antibiotic during the exacerbation	40/58 (69.0%)

Abbreviations: Inhaled corticosteroids (ICS), long-acting beta-agonist (LABA), long-acting muscarinic antagonist (LAMA), oral corticosteroid (OCS).

Figure 1. Flow chart of COPD patients/samples groups analyzed. Seventy-eight participants provided at least one sputum sample during the study. A total of 148 sputum samples were included in this study, consisting of 58 exacerbation-related (E1) sputum samples (from 58 patients) and 62 sputum samples (from 58 patients) two weeks after the exacerbation episode (E2).

Abbreviations: “E1: exacerbation event; E2: 14 days after the exacerbation event and the appropriate treatment; HRV: human rhinovirus; SPU: sputum sample”.

Figure 2. The prevalence of the pulmonary exacerbations of COPD patients (N=58) plotted over the duration of the study. the prevalence of pulmonary exacerbations of COPD was recorded across the entire study interval (November 2021 to October 2022). The prevalence of COPD exacerbation was higher throughout the winter and autumn months followed by the spring months, with the lowest level of detection occurring in the summer months.

Abbreviations: “COPD: chronic obstructive pulmonary disease”.

Table 3. HRV detection rates during the study period: the overall prevalence of HRV in the non-matched samples and participants.

State	HRV-positivity in the samples (n=120)	HRV-positivity in the study participants (n=58)
V1E1	3/15 (19%)
V2E1	1/18 (5%)
V3E1	5/18 (31%)
V4E1	2/7 (29%)
E1 (total)	11/58 (19%)	11/58 (19%)
V2E2	4/14 (45%)
V3E2	4/21 (19%)
V4E2	4/19 (20%)
V5E2	3/8 (38%)
E2 (total)	15/62 (24%)	15/58 (26%)

Abbreviations: “E1: exacerbation event; E2: 14 days after the exacerbation event and the appropriate treatment; V: visit”.

Table 4. The difference in the proportion of HRV-positivity at the E1 and E2 states (N = 52 paired COPD patients).

		E2
		HRV-negative	HRV-positive	Total (%)
E1	HRV-negative	32	10	42 (81%)
	HRV-positive	6	4	10 (19%)
	Total (%)	38 (73%)	14 (27%)	52 (100%)

Four patients experienced HRV detection during both E1 and E2. Ten patients experienced HRV detection only during the E2. 15 HRV-positive patients at the E1 state becoming HRV-negative at E2 state. The related samples McNemar’s test with continuity correction was used to conclude whether a difference exists in the proportion of HRV-positive at the E1 and E2 states. The proportion of HRV-positive increased from the E1 state value of 19% to 27% at E2, a statistically insignificant difference, χ2 [1] = 0.562, p = 0.454.

Abbreviations: “E1: exacerbation event; E2: 14 days after the exacerbation event and the appropriate treatment”.

Figure 3. The numbers of HRV detections throughout the study. The prevalence of HRV-positive samples was recorded across the entire study interval (November 2021 to October 2022). HRV was detected throughout winter and spring, with the lowest level of detection occurring in the summer months.

Abbreviations: “E1: exacerbation event; E2: 14 days after the exacerbation event and the appropriate treatment; HRV: human rhinovirus”.

Table 5. Summary of cases showing twice HRV detection during the study period (n = 5 patients).

Patient ID	V1E1	V3E1	V2E2	V4E2	V5E2
Patient_1	-	Pos Feb	-	Pos Feb	-
Patient_2	Pos Oct	-	Pos Oct	-	-
Patient_3	-	Pos Apr	-	-	Pos May
Patient_4	-	Pos Feb	-	Pos Feb	-

This table shows five patients who experienced dual detection of HRV during the study, concerning the time (month) of the HRV detection. The symbol (-) indicates no visit/event happened (no sample).

Abbreviations: Pos: positive; Neg: negative.

Global Initiative for Chronic Obstructive Lung Disease. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease (GOLD). Internet. 2023. https://goldcopd.org/2023-gold-report-2/

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