Epidemiology and Infection

Research Article

Excess hospital admissions for pneumonia and influenza in persons [gt-or-equal, slanted]65 years associated with influenza epidemics in three English health districts: 1987–95

J. S.  NGUYEN-VAN-TAM  a1 c1, C. R.  BROCKWAY  a2, J. C. G.  PEARSON  a1, A. C.  HAYWARD  a1 and D. M.  FLEMING  a3
a1 Division of Public Health Medicine and Epidemiology, School of Community Health Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
a2 Department of Public Health, Lincolnshire Health Authority, Lincoln, UK
a3 Royal College of General Practitioners Research Unit, Birmingham, UK


Objectives: To study the association between community influenza activity and acute hospital admissions for pneumonia and influenza among elderly persons.

Design: Multiple regression analysis of acute hospital admissions against community influenza activity, air temperature and seasonal and long-term trends.

Setting: Three English health districts: 1987–95.

Subjects: Persons aged [gt-or-equal, slanted]65 years.

Outcome measures: Acute hospital admissions for pneumonia and influenza (ICD9: 480–487); excess hospital admissions during epidemic periods.

Results: The final regression model explained 70% of the total variation in hospital admissions for pneumonia and influenza, including 14% due to community influenza activity. However, most variation was explained by long-term and seasonal changes unrelated to influenza. In the large influenza epidemic of 1989/90 a typical health district (500000 total population) experienced 56 excess admissions for pneumonia and influenza attributable to epidemic influenza among persons aged [gt-or-equal, slanted]65 years, requiring 672 additional bed-days. However the figure varied widely between seasons and over the whole study period, the average winter excess was 17·5 admissions per health district, requiring an additional 210 bed-days.

Conclusions: Influenza epidemics exert a variable impact on acute hospital admissions for pneumonia and influenza among elderly persons, which in the past have been poorly quantified. Although the absolute numbers of excess admissions is modest, their impact on bed availability may be considerable because of the duration of hospital stay in elderly persons.

(Accepted September 10 2000)

c1 Author for correspondence.