Indirect Cost of Illness Study of Moderate and Severe Asthma in Quebec

Study Overview
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Brief Summary
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Rationale Asthma is a chronic inflammatory disorder of the airways affecting persons of all ages and is recognized as one of the most common chronic diseases. Canada has one of the highest asthma prevalence rates in the world (8.5%, aged 12 and over) and it is a major cause of hospitalization. The cost of asthma varies dramatically across disease severity, and it is expected that these costs are greater when the condition is sub-optimally managed and controlled. Although a number of publications have been reported on the economic burden of asthma, there is a lack of information on the cost of asthma based on disease severity and level of disease control in Canada. The proposed study aims to i) estimate the annual indirect cost of asthma and ii) the impact of asthma on absenteeism, presenteeism and work productivity in Canada. This information is essential to further quantify the burden of asthma on patients and the healthcare system in the Canadian setting. Overall Objectives The overall objective of this study is to describe the impact of asthma on patients with moderate to severe asthma and to estimate the indirect costs of asthma care in asthmatic patients followed in tertiary clinics specialized in the field of asthma in Quebec, Canada. Study Design A prospective cohort study will be conducted to measure the indirect economical burden of asthma on patients. Patients will be selected and recruited from the BD-Asthma registry and followed prospectively for 1 year. Recruited patients will be asked to complete questionnaires at regular intervals for 1 year to measure indirect cost of disease, using the Valuation of lost productivity (VOLP) questionnaire. Data Collected For each patient, the following data will be collected Patient demographics Age Sex Income Level of education Smoking Disease management and Treatment utilization in the year prior to recruitment Physician visits and follow up Hospitalizations (number and total days) Emergency room visits Disease characteristics Asthma history Year of first diagnosis of asthma severity Asthma Control Questionnaire score Lung function measures Data Analysis Methods For each participant, the percentage of time missed from work over a year will be calculated. We will use the human capital approach to calculate the costs of asthma due to lost productivity, incorporating both absenteeism and presenteeism in the calculation of the productivity loss. We will calculate the number of work days in which the person was unable to attend the workplace, and the number of days and percentage of time lost during the days the person's work was affected by their asthma. The fraction of time lost from work in the past year will be multiplied by the average income in Quebec. Finally, this value will be multiplied by the coefficient generated by the VOLP, which reflects the relative value of the productivity loss. In addition, we will calculate the VOLP multiplier for each participant which, combined with the percentage of time missed from work, will create a measure of productivity loss adjusted for the relative importance and replace-ability of the participant's profession. Sample Size and Power One hundred subjects will be randomly selected from the BD-Asthma registry. Limitations The study population may not be representative of the general asthma population, as moderate to severe asthma will be over represented in these tertiary centers.

Detailed Description
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Rationale Asthma is a chronic inflammatory disorder of the airways affecting persons of all ages and is recognized as one of the most common chronic diseases. With a continuously increasing prevalence and associated morbidity and mortality, asthma poses a tremendous clinical and economic burden on healthcare systems and on the society as a whole. According to a report published by the Global Initiative for Asthma (GINA) in 2004 an estimated 300 million people in the world have asthma, and more than 2 million Canadians have asthma. Canada has one of the highest asthma prevalence rates in the world (8.5%, aged 12 and over) and it is a major cause of hospitalization. The direct and indirect costs associated with asthma are expected to rank among the highest for chronic diseases due to the high prevalence in conjunction with the significant healthcare utilization associated with the disease and the considerable restrictions asthma imposes on the physical, emotional, social, and professional lives of sufferers. The cost of asthma varies dramatically across disease severity, and it is expected that these costs are greater when the condition is sub-optimally managed and controlled. Although a number of publications have been reported on the economic burden of asthma, there is a lack of information on the cost of asthma based on disease severity and level of disease control in Canada. Moreover, no study has compared the annual cost of uncontrolled and well-controlled asthma patients. Although population-level direct costs have been previously reported through the use of administrative healthcare databases in various provinces, these databases cannot provide clinical data and are limited to subjects who have a public drug insurance plan. The proposed study aims to i) estimate the annual indirect cost of asthma and ii) the impact of asthma on absenteeism, presenteeism and work productivity in Canada. This information is essential to further quantify the burden of asthma on patients and the healthcare system in the Canadian setting. Overall Objectives The overall objective of this study is to describe the impact of asthma on patients with moderate to severe asthma and to estimate the indirect costs of asthma care in asthmatic patients followed in tertiary clinics specialized in the field of asthma in Quebec, Canada. Primary objectives To estimate the annual indirect costs of asthma in asthmatic patients followed in tertiary clinics specialized in the field of asthma in Quebec, Canada To estimate the annual indirect cost of asthma by asthma severity and control status (uncontrolled, partly controlled, well controlled) of asthmatic patients followed in tertiary clinics specialized in the field of asthma in Quebec, Canada Secondary objectives • To determine the impact of asthma on work productivity in asthmatic patients followed in tertiary clinics specialized in the field of asthma in Quebec, Canada. Study Design A prospective cohort study will be conducted to measure the indirect economical burden of asthma on patients. Patients will be selected and recruited from the BD-Asthma registry and followed prospectively for 1 year. Recruited patients will be asked to complete questionnaires at regular intervals for 1 year to measure indirect cost of disease, using the Valuation of lost productivity (VOLP) questionnaire. Recruitment of patients All eligible patients from the BD-asthma will be invited to participate. Patients approached for participation will be provided verbal and written information on the project and, if the patient agrees to participate, they will be asked to sign the participation consent form. The forms will be collected by the research coordination centre (either at the clinic or the physicians' office or directly with the patient). All recruited eligible patients that have provided their consent will be included in this study. Source Population The population is defined as individuals diagnosed with asthma (ICD9 codes 493.x). Study Population The study population is defined as having had at least one diagnosis of asthma (ICD9 codes 493.x) recorded in the BD Asthma database between February 2010 and February 2012. Clinical information Patient characteristics and clinical information on asthma will be obtained from the BD-asthma database. Data Collected For each patient, the following data will be collected Patient demographics Age Sex Income Level of education Smoking Disease management and Treatment utilization in the year prior to recruitment Physician visits and follow up Hospitalizations (number and total days) Emergency room visits Disease characteristics Asthma history Year of first diagnosis of asthma severity Asthma Control Questionnaire score Lung function measures Data Analysis Methods For each participant, the percentage of time missed from work over a year will be calculated. We will use the human capital approach to calculate the costs of asthma due to lost productivity, incorporating both absenteeism and presenteeism in the calculation of the productivity loss. We will calculate the number of work days in which the person was unable to attend the workplace, and the number of days and percentage of time lost during the days the person's work was affected by their asthma. The fraction of time lost from work in the past year will be multiplied by the average income in Quebec. Finally, this value will be multiplied by the coefficient generated by the VOLP, which reflects the relative value of the productivity loss. In addition, we will calculate the VOLP multiplier for each participant which, combined with the percentage of time missed from work, will create a measure of productivity loss adjusted for the relative importance and replace-ability of the participant's profession. Sample Size and Power One hundred subjects will be randomly selected from the BD-Asthma registry. Limitations The study population may not be representative of the general asthma population, as moderate to severe asthma will be over represented in these tertiary centers.

Official Title
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Indirect Cost of Illness Study of Moderate and Severe Asthma in Quebec

Conditions
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Asthma

Intervention / Treatment
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* Other: Valuation of lost productivity questionnaire
* Other: Work productivity and activity impairment questionnaire


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Part of the BD-Asthma registry Age 18 years and older Patients who signed consent for research with the BD-Asthma registry and signed consent to participate in the indirect cost study. Must be alive at the time of recruitment Exclusion Criteria: • Patients with a diagnosis of COPD recorded in BD-Asthma at the time of enrolment.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Arm 1<br>Intervention 1 & 2 are associated with Arm 1. All patients enrolled in the study will possibly receive both the valuation of lost productivity and work productivity and activity impairment questionnaires, which are outside of the patient's usual care. | Other: Valuation of lost productivity questionnaire<br>* A new, composite questionnaire that can be used to assess the impact of health conditions on lost productivity in monetary units. It measures absenteeism, presenteeism, and non work activities.<br>Other: Work productivity and activity impairment questionnaire<br>* A six item questionnaire used as a patient-reported quantitative assessment of the amount of absenteeism, presenteeism, and daily activity impairment attributable to a specific health problem.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Indirect Cost of Asthma Per Participant Per 3 Months at Baseline (BL) and 12-month Follow-up (FUP) | Participants completed questionnaires within 2 weeks post-recruitment, 4, 8 and 12 months to measure indirect cost of disease, specifically related to productivity. The following questionnaires were used: WPAI helps to determine presenteeism, absenteeism, and total cost calculation (TCC) possible (number of days during the year of study), while VOLP is used to assess the impact of health conditions on lost productivity in monetary units (United states dollars). The following parameters were calculated: Cost of absenteeism due to asthma (CAA), cost of presenteeism due to asthma (CPA), cost of absenteeism due to asthma in whom TCC was possible (CAA TCC), cost of presenteeism due to asthma in whom TCC was possible (CPA TCC), and total indirect cost due to asthma (TICA). | BL and at 12-month FUP | 
| Indirect Cost of Asthma by Level of Asthma Control Per Participant Per 3 Months at BL and 12-month FUP | Costs of asthma are greater when the asthma is sub-optimally managed and controlled and varies depending on the par. asthma control. Asthma control was assessed using the Asthma Control Questionnaire (ACQ) and par. were asked to recall their experiences during the previous week and respond to the 6 specified questions on a 7-point Likert scale (0=well-controlled; 6=maximum impairment [poorly controlled]; a score of ≤0.75 indicates well controlled symptoms. The following parameters were presented: Cost of absenteeism due to asthma (CAA), cost of presenteeism due to asthma (CPA), cost of absenteeism due to asthma in whom TCC was possible (CAA TCC), cost of presenteeism due to asthma in whom TCC was possible (CPA TCC), and total indirect cost due to asthma (TICA). Only 59 par. were active workers. When stratified by asthma control and severity each stratum had a sample less than 59. Although results are presented. data may not be reliable due to the low number of par. in each stratum. | BL and 12-month FUP | 
| Indirect Cost of Asthma by Level of Asthma Severity Per Participant Per 3 Months at BL and 12-month FUP | Costs of asthma may vary depending on the participant's asthma severity. Asthma severity was based on the standard definitions for severity and ACQ scores: Mild (<0.75), Moderate (>0.75) and Severe (any ACQ score). The following parameters were presented: Cost of absenteeism due to asthma (CAA), cost of presenteeism due to asthma (CPA), cost of absenteeism due to asthma in whom TCC was possible (CAA TCC), cost of presenteeism due to asthma in whom TCC was possible (CPA TCC), and total indirect cost due to asthma (TICA). | BL and 12-month FUP | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Work Productivity Loss as Assessed in Hours Using Work Productivity and Activity Impairment (WPAI) During the Specified Time Points | WPAI is a self-administered instrument to determine the degree to which asthma affected work productivity while at work and affected activities outside of work in the last 7 days and yields 4 types of scores: Absenteeism (work time missed/missed due to other reasons); Presenteeism (actual time worked); Work Productivity Loss (affected productivity while working); and Activity Impairment (affected regular activities). The following parameters were presented: Hours (Hrs) missed due to asthma (HMA), Hrs missed due to other reasons (HMO), and Hrs actually worked (HAW); all in the last 7 days. | At BL, 4-Month, 8-Month and 12-Month FUP | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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asthma, indirect cost