Clinical trial NCT01683630: Comparison of Epidemiology and Clinical Outcomes of Influenza A & B Cases in Manitoba, Canada
Official title: Comparison of the Epidemiology and Clinical Outcomes of Laboratory-Confirmed Influenza A and Influenza B Cases in Manitoba, Canada
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Influenza
Keywords: Influenza
Influenza type A
Influenza type B
hospitalization
Manitoba
Canada
Lead sponsor: International Centre for Infectious Diseases, Canada
Sponsor class: OTHER
First posted: 2012-09-12
Enrollment: 1849
Sex: ALL
Minimum age (years): 6
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: RETROSPECTIVE
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.

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.

Eligibility criteria: 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:

Primary outcomes:
measure: 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
timeFrame: up to 15 years
measure: 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
timeFrame: upto 15 years
measure: 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
timeFrame: Upto 15 years
Secondary outcomes:
Other outcomes:
Locations:
city: Winnipeg
country: Canada
facility: International Centre for Infectious Diseases
state: Manitoba
Study officials:
affiliation: Associate Professor, University of Manitoba
name: Salah Mahmud, MD, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: 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.