Measuring the impact of influenza on the hospital admission rates of the elderly in Ontario: a five-year admission rate analysis, 1988-1993

Objective — A retrospective study was conducted to compare age- and sex-specific rates of hospital admission of the elderly in Ontario for five influenza seasons from 1988-1993 for pneumonia, congestive heart failure and chronic respiratory disease.

Results — Significant increases in admissions were found for pneumonia in each influenza season for both sexes. Admissions were significantly increased for congestive heart failure for the oldest males in all years; and for four of five years for the youngest two age groups of males. For females significant increases in admissions occurred in the oldest two age groups in each influenza season; and for three of five seasons for the youngest age group. For chronic respiratory disease, significant increases in admissions were found for each influenza season for all years for the two youngest age groups of males and females.

Conclusion — The impact of influenza is substantial in terms of morbidity in the elderly.