Influenza in Malaysian adult patients hospitalized with community-acquired pneumonia, acute exacerbation of chronic obstructive pulmonary disease or asthma: a multicenter, active surveillance study

Yong Kek Pang,Adelina Cheong,Lilian Phei Lian Wang,Jiunn Liang Tan,Mohd Arif Mohd Zim,Chee Loon Leong,Mau Ern Poh,Ahmad Izuanuddin Ismail,Joanne Zhi Han Lau,Kee Sing Ng,Yoke Fun Chan,I-Ching Sam,Yoong Min Chong,Paras Doshi,Anne-Frieda Taurel,Jean Khor,Aisya Natasya Musa

doi:10.1186/s12879-021-06360-9

Abstract

BackgroundAvailable data on influenza burden across Southeast Asia are largely limited to pediatric populations, with inconsistent findings.MethodsWe conducted a multicenter, hospital-based active surveillance study of adults in Malaysia with community-acquired pneumonia (CAP), acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and acute exacerbation of asthma (AEBA), who had influenza-like illness ≤10 days before hospitalization. We estimated the rate of laboratory-confirmed influenza and associated complications over 13 months (July 2018–August 2019) and described the distribution of causative influenza strains. We evaluated predictors of laboratory-confirmed influenza and severe clinical outcomes using multivariate analysis.ResultsOf 1106 included patients, 114 (10.3%) were influenza-positive; most were influenza A (85.1%), with A/H1N1pdm09 being the predominant circulating strain during the study following a shift from A/H3N2 from January–February 2019 onwards. In multivariate analyses, an absence of comorbidities (none versus any comorbidity [OR (95%CI), 0.565 (0.329–0.970)], p = 0.038) and of dyspnea (0.544 (0.341–0.868)], p = 0.011) were associated with increased risk of influenza positivity. Overall, 184/1106 (16.6%) patients were admitted to intensive care or high-dependency units (ICU/HDU) (13.2% were influenza positive) and 26/1106 (2.4%) died (2.6% were influenza positive). Males were more likely to have a severe outcome (ICU/HDU admission or death).ConclusionsInfluenza was a significant contributor to hospitalizations associated with CAP, AECOPD and AEBA. However, it was not associated with ICU/HDU admission in this population.Study registration, NMRR ID: NMRR-17-889-35,174.

Highlights

Influenza is associated with substantial disease burden worldwide, with estimated annual attack rates of 5–10% in adults and 20–30% in children [1]
Study design and patients This was a prospective epidemiological active surveillance study, adapted from the Global Influenza Hospital Network protocol [11], conducted in three hospitals located in the Klang Valley area in Malaysia over a one-year period, from July 2018 to August 2019
Most (75.8%) patients had a diagnosis upon admission to hospital that included community-acquired pneumonia (CAP), 21.6% had acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and 29.6% had acute exacerbation of asthma (AEBA); the most common comorbidities were cardiovascular disease (49.2%) and diabetes (36.2%)

Summary

Introduction

Influenza is associated with substantial disease burden worldwide, with estimated annual attack rates of 5–10% in adults and 20–30% in children [1]. Southeast Asia was estimated to have one of the highest influenza-associated mortality rates (3.5–9.2 per 100, 000 individuals), along with sub-Saharan Africa (2.8– 16.5 per 100,000 individuals) [5]. These estimates were based on data collected from 33 contributing countries (two in Southeast Asia) extrapolated to countries that had limited to no information available from vital records and viral surveillance making these results reliant on extrapolation [5]. Available data on influenza burden across Southeast Asia are largely limited to pediatric populations, with inconsistent findings

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Conclusion