Comparison of Epidemiology and Clinical Outcomes of Influenza A & B Cases in Manitoba, Canada

Completed

Conditions: Influenza

Registration Number: NCT01683630

Lead Sponsor: International Centre for Infectious Diseases, Canada

Brief Summary: This study compares the epidemiology and clinical outcomes of laboratory confirmed influenza type A to type B following clinical diagnosis of influenza. Multivariate models are used to assess the effects of influenza type on clinical outcomes while accounting for potential confounders.

Detailed Description: Annual epidemics of influenza are an important public health problem globally and in Canada. Each year, 10-25% of the Canadian population become infected with influenza. Most of these infections are typically asymptomatic or associated with a mild self-limiting illness. However, influenza can cause severe illness leading to hospitalization and death, especially among the very young, the elderly and among those with underlying chronic conditions. It has been estimated that on average about 4,000 influenza-related deaths occur in Canada each year. In addition, the economic burden of influenza is significant because of the high direct costs associated with increased utilization of services and the indirect costs caused by school and work absenteeism.

This project compares laboratory-confirmed cases of influenza A and B in terms of their epidemiology, and the overall and cause-specific incidence rates of important clinical outcomes including physician visits, hospitalization and death following clinical diagnosis of influenza cases in Manitoba over the period from 1993 to 2008.

The study assesses secular and seasonal trends in the incidence rates of influenza A and B cases in Manitoba during the period of 1993-2008, to determine whether these rates vary for different subsets of the population defined by demographic (e.g., age group, gender), socioeconomic, geographic (neighborhood of residence) and clinical (e.g., vaccination, presence of chronic conditions, immune status) characteristics.

The analysis by influenza type then compares the overall and cause-specific incidence rates of physician visits, hospitalization and death following the diagnosis of a laboratory-confirmed influenza. The effects of influenza type on clinical outcomes (e.g., hospitalization) are assessed with multivariate models while accounting for potential confounding by demographic, socioeconomic, geographic and clinical (e.g., co-morbidity, immune status) characteristics.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 1849

Inclusion Criteria

Any person who normally resides in Manitoba and who has been continuously covered by Manitoba Health during the study period will be eligible for inclusion in the study.

Exclusion Criteria

Not provided

Study & Design

Study Type: OBSERVATIONAL

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Percentage of Participants With a Risk of Hospitalization Due to Any Diagnosis Within 30 Days Following the Index Date of Confirmed Cases of Influenza A and B in the Province of Manitoba	upto 15 years
Age Adjusted Percentage of Participants With a Physician Visit Due to Any Diagnosis Within 30 Days of the Index Date of the Confirmed Influenza A and B Cases in the Province of Manitoba	up to 15 years
Risk of Death Due to Any Cause During 30 Days Following the Index Date of Laboratory Confirmed Cases of Influenza A and B in the Province of Manitoba	Upto 15 years

Secondary Outcome Measures