Population-based estimates of the burden of pneumonia hospitalizations in Hong Kong, 2011–2015

  • Xue Li
  • Joseph E. Blais
  • Ian C. K. Wong
  • Anthony W. Y. Tam
  • Benjamin J. Cowling
  • Ivan F. N. Hung
  • Esther W. Y. ChanEmail author
Original Article


Up-to-date data on the burden of disease are important to identify patients with unmet needs and to optimize healthcare resources. We aimed to characterize the burden of pneumonia hospitalizations in Hong Kong and inform targeted healthcare policies for pneumonia control in the era of global aging. This was a population-based study using a territory-wide administrative electronic health record system that covers all public hospitals of Hong Kong. Patients admitted to public hospitals, from 2011 to 2015, with a diagnosis of pneumonia at discharge were identified based on the International Classification of Diseases-Ninth Revision-Clinical Modification Codes (480–486 and 487.0). Incidence, inpatient case-fatality, all-cause fatality, 28-day readmission, hospital length of stay, and healthcare costs were assessed for seven age strata. We identified 323,992 patients (median age 80 years, 44.4% female) with hospitalized pneumonia (organism unspecified 84.2%; bacterial pneumonia 12.3%; viral pneumonia 2.5%; others 1.0%). Annual incidence was 955.1 per 100,000 population, with a 10.6% decrease from 2011 to 2015. Case-fatality, all-cause fatality, and 28-days readmission risks were 13.8, 21.6, and 19.5%, respectively. The average hospital length of stay was 14.1 days with corresponding direct costs of $9348 USD per episode in the monetary value of 2015. Individuals aged ≥ 65 years accounted for over 75% of pneumonia-related hospitalizations, 90% of deaths, and the majority of healthcare costs. Hospitalized pneumonia represents a considerable health and economic burden in Hong Kong, especially in older adults. The study provides a population-level baseline estimate for further cost-effective evaluation of targeted strategies for pneumonia control.


Pneumonia admission Burden of disease Healthcare resource Elderly care Population aging 



We thank Dr. Hou Jing from the Department of Family Medicine and General Out-patient Clinic, Kowloon Central Cluster, Hospital Authority for her clinical advice on clinical and economic burden estimation. We acknowledge Dr. In Hye Suh from the Department of Pharmacology and Pharmacy, University of Hong Kong, for proof-reading of the manuscript.

Author contributions

Conception and design of the work: ICW, BJC, IFH, and EWC; data collection and analysis: XL and AWT; results interpretation: all authors; drafting the article: XL; critical revision of the article: XL, JB, BJC, IFH, and EWC; study supervision: EWC. Final approval of the version to be published: all authors.

Funding information

This work was partially supported by an Investigator-Initiated Research Grant from Pfizer Corporation Hong Kong Limited (grant number: WI214458). Pfizer had no role in the study design, data collection, statistical analysis, interpretation, or writing of the manuscript. The corresponding author was responsible for the content of the manuscript and the decision to submit for publication.

Compliance with ethical standards

Ethical approval and consent to participate

The study was approved by the Institutional Review Board of The University of Hong Kong/Hospital Authority Hong Kong West Cluster (reference number: UW16-327). Informed patient consent was waived as the data used in this study were de-identified.

Consent for publication

Not applicable.

Competing interests

EWC has received the Early Career Scheme and the General Research Fund from the Hong Kong Research Grants Council; Health and Medical Research Fund from the Food and Health Bureau of Hong Kong; internal funding from The University of Hong Kong; and research funding from Bristol-Myers Squibb, Pfizer, and Janssen, all unrelated to the current work. BJC has received research funding from Sanofi Pasteur and consulting fees from Roche, all unrelated to the current work. The other co-authors declare that they have no conflict of interest.

Supplementary material

10096_2018_3459_MOESM1_ESM.docx (16 kb)
ESM 1 ICD-9-CM diagnostic/procedure codes for identifying medical conditions. List of International Classification of Diseases-Ninth Revision-Clinical Modification (ICD-9-CM) codes used for identifying the medical conditions of target patients (DOCX 15 kb)
10096_2018_3459_MOESM2_ESM.docx (16 kb)
ESM 2 British National Formulary categories for relevant antimicrobials (5.1–5.3). List of British National Formulary categories for identifying the antimicrobial treatments of target patients (DOCX 16 kb)
10096_2018_3459_MOESM3_ESM.docx (16 kb)
ESM 3 Pneumonia-type distribution based on ICD9-CM Code. Detailed pneumonia-type distribution among the overall all-cause pneumonia (DOCX 15 kb)
10096_2018_3459_Fig4_ESM.png (147 kb)

Incidence of hospitalized pneumonia by age and sex. Middle line in the box: median value; upper and lower line of the box: interquartile ranges (PNG 146 kb)

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High-resolution image (TIFF 1078 kb)
10096_2018_3459_Fig5_ESM.png (53 kb)

Average length of stay of hospitalized pneumonia by age, 2011–2015 (PNG 52 kb)

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High-resolution image (TIFF 12003 kb)
10096_2018_3459_Fig6_ESM.png (49 kb)

Readmission of hospitalized pneumonia by age, 2011–2015 (PNG 49 kb)

10096_2018_3459_MOESM6_ESM.tiff (11.7 mb)
High-resolution image (TIFF 12003 kb)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Xue Li
    • 1
  • Joseph E. Blais
    • 1
  • Ian C. K. Wong
    • 1
    • 2
  • Anthony W. Y. Tam
    • 1
  • Benjamin J. Cowling
    • 3
  • Ivan F. N. Hung
    • 4
    • 5
  • Esther W. Y. Chan
    • 1
    Email author
  1. 1.Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, Laboratory BlockUniversity of Hong KongHong Kong Special Administrative RegionChina
  2. 2.Research Department of Practice and PolicyUCL School of PharmacyLondonUK
  3. 3.WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of MedicineUniversity of Hong KongHong Kong Special Administrative RegionChina
  4. 4.Carol Yu Centre for Infection and Division of Infectious Diseases, State Key Laboratory of Emerging Infectious Diseases, Department of Microbiology, Queen Mary HospitalUniversity of Hong KongHong Kong Special Administrative RegionChina
  5. 5.Department of Medicine, Queen Mary HospitalUniversity of Hong KongHong Kong Special Administrative RegionChina

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