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

Comparison of the Epidemiology and Clinical Outcomes of Laboratory-Confirmed Influenza A and Influenza B Cases in Manitoba, Canada

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.

Study Overview

• Status: Completed
• Conditions: Influenza

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.

• Study Type: Observational
• Enrollment (Actual): 1849

Contacts and Locations

Study Locations

• Canada
  • Manitoba
    • Winnipeg, Manitoba, Canada, R3B 3P5
      • International Centre for Infectious Diseases

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 6 months and older (Child, Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

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

Description

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:

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Confirmed influenza A and B cases; Cases of influenza A and B as diagnosed by PCR, viral culture or florescence microscopy

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
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
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
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

Collaborators and Investigators

• Sponsor: International Centre for Infectious Diseases, Canada
• Investigators: Principal Investigator: Salah Mahmud, MD, PhD, Associate Professor, University of Manitoba

Publications and helpful links

General Publications

• Hinds AM, Bozat-Emre S, Van Caeseele P, Mahmud SM. Comparison of the epidemiology of laboratory-confirmed influenza A and influenza B cases in Manitoba, Canada. BMC Public Health. 2015 Jan 30;15:35. doi: 10.1186/s12889-015-1351-z.

Study record dates

Study Major Dates

• Study Start: April 1, 2012
• Primary Completion (Actual): September 1, 2012
• Study Completion (Actual): September 1, 2012

Study Registration Dates

• First Submitted: August 31, 2012
• First Submitted That Met QC Criteria: September 7, 2012
• First Posted (Estimate): September 12, 2012

Study Record Updates

• Last Update Posted (Estimate): October 10, 2016
• Last Update Submitted That Met QC Criteria: August 29, 2016
• Last Verified: August 1, 2016

More Information

Terms related to this study

• Keywords: Influenza; hospitalization; Manitoba; Canada; Influenza type A; Influenza type B
• Additional Relevant MeSH Terms: RNA Virus Infections; Virus Diseases; Infections; Respiratory Tract Infections; Respiratory Tract Diseases; Orthomyxoviridae Infections; Influenza, Human
• Other Study ID Numbers: ICID-2012-FLU-A,B-02

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO