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. 2022 Jan 6:17:25-32.
doi: 10.2147/COPD.S338757. eCollection 2022.

Predictors of Influenza PCR Positivity in Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Calvin You Jia Chen  1 , Min Sen Yew  2 , John Arputhan Abisheganaden  3 , Huiying Xu  3
Affiliations

Predictors of Influenza PCR Positivity in Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Calvin You Jia Chen et al. Int J Chron Obstruct Pulmon Dis. .

Abstract

Purpose: Influenza infection is an important cause of acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Clinical features predicting influenza PCR positivity are unknown. We aim to identify predictors of influenza PCR positivity in AECOPD.

Patients and methods: A retrospective study of AECOPD cases admitted between 1st January 2016 to 30 June 2017 with combined nasal/throat swabs sent for influenza PCR (Xpert Xpress Flu/RSV) within 24 hours of admission was performed. Clinical parameters and investigations within 24 hours of admission were retrieved from electronic medical records.

Results: Influenza PCR were sent for 925 AECOPD cases (mean age 75 years, 87.9% male). There were 90 PCR positive cases (68 Influenza A, 22 Influenza B). Influenza PCR positive cases had higher temperatures, higher heart rates, lower white cell and lower eosinophil counts. Age, gender, COPD severity, comorbidities and smoking status were similar in both groups. There were no differences in blood pressure, oxygen status, neutrophil or lymphocyte counts, C reactive protein, procalcitonin or chest X-ray consolidation between groups. Higher temperature, higher heart rate, white cell count in the lowest quartile (Q1 < 8.1 x109/L) and non-eosinophilic exacerbations predicted influenza PCR positivity on univariate logistic regression and these factors remained significant after multivariate adjustment (temperature adjusted odds ratio [adj OR] 1.324 [1.009-1.737], p = 0.043; heart rate adj OR 1.017 [1.004-1.030], p = 0.011; white cell count Q1 adj OR 3.330 [1.690-6.562], p = 0.001; eosinophilic exacerbations adj OR 0.390 [0.202-0.756], p = 0.005).

Conclusion: Higher temperature, higher heart rate, low white cell count (especially when < 8.1 x109/L) and non-eosinophilic exacerbations are independent predictors of influenza PCR positivity in AECOPD cases.

Keywords: chronic obstructive pulmonary disease; eosinophil; exacerbation; influenza.

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Conflict of interest statement

The authors do not have any relevant conflict of interests to declare. The authors did not receive funding for this study.

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