Effect on Attendance if Including Focused Information of Spirometry in Preventive Health Checks
Condition: Spirometry; Patient Participation; Health Literacy; Lung Diseases
MeSH terms: Lung Diseases
Study type: Interventional

Summary: 
      The purpose of this study is to investigate if focused information of spirometry in the
      invitation to preventive health checks will increase the attendance compared with a standard
      invitation to preventive health checks.
    

Detailed description: 
      Background:

      Lung diseases are among the most frequent and most serious ailments in Denmark. Chronic
      obstructive pulmonary disease (COPD) is the fourth most frequent cause of death and
      represents a significant burden on the health care system, the patients and their relatives.
      The National Board of Health in Denmark recommends spirometry to all individuals over 35
      years who present at least one respiratory symptom (dyspnea, cough, wheeze or sputum
      production) or risk factors (prior or current smoking or relevant occupational exposure) in
      order to facilitate early detection of COPD. However approximately 200,000 citizens with COPD
      remain undiagnosed and unknown to the health care system.

      Preventive health checks including spirometry can be used to detect lung diseases earlier. In
      a Danish municipality, the Check your Health Preventive Programme (CHPP) was initiated,
      offering preventive health checks to all 30 to 49 year-old citizens. This health promotion
      program provides the unique opportunity to evaluate single components of preventive health
      check in a real-life setting. Only a few previous studies have included spirometry in a
      preventive health check.

      Over time the attendance at preventive health checks has decreased and at present the
      response rate is approximately 50%. Little is known about initiatives that can influence the
      attendance rate according to preventive health checks.

      The aim of the study is to examine whether focused information on spirometry in the
      invitation material will influence the attendance in preventive health checks. The
      investigators hypothesize that spirometry as part of the preventive health check will
      increase the attendance in CHPP from 53% to 58% and the increase will be among prior and
      current smokers.

      Materiel/Methods:

      Check your health preventive program (CHPP):

      The present study is embedded in the fourth year of the above mentioned CHPP. In CHPP, all
      citizens living in the municipality of Randers aged 30-49 years per 1st of January 2012 were
      identified in the Danish Civil Registration System. CHPP is a house-hold cluster randomized
      controlled trial offering a preventive health check to all 30 to 49 year old citizens in a
      Danish municipality during the years 2012 to 2017 (n= 26,216). The citizens were randomized
      by household into 5 groups of equal size, each corresponding to a specific year where they
      would be invited to a health check. Invitations with a prefixed appointment for the health
      check and information about the health check were dispatched continuously

      Setting:

      The health checks and the subsequent health behavioral courses are performed at a local
      health care center. The subsequent health interview takes place at the participants own
      general practitioner. The health checks will be conducted by health professionals who have
      experience with all measurement procedures as well as in risk communication to ensure
      standardization and quality.

      The health check:

      Prior to the health check the participants are asked to answer a web-based questionnaire
      regarding physical activity, self-rated health, mental health, smoking and alcohol. The
      clinical examination include following measures: biochemical (total cholesterol, lower
      density lipoprotein (LDL), glycated hemoglobin (HbA1c)), systolic and diastolic blood
      pressure, bodyweight, height, spirometry and Aastrands submaximal bike-test
      (cardiorespiratory fitness). At the end of the health check, the results are presented in a
      profile pamphlet including recommendations for follow up according to their risk-profile.

      Execution of the health check is standardized by a written protocol and adherence is checked
      continuously.

      Questionnaire:

      Based on questionnaire data the following categorical variables will be described for all
      attendees:

        -  Age will be divided into four groups; 30-35, 36-40, 41-45 and 46-50

        -  Smoking status will be classified as smoker, ex-smoker, or never smoker and supplied
           with information about pack years.

        -  Airway symptoms (dyspnoea, wheezing or coughing) during the last four weeks will be
           divided into

        -  All of the time

        -  Most of the time

        -  Now and then

        -  Rarely

        -  Not at all

      The present study:

      This is a randomized controlled trial on attendance in preventive health check. From November
      2015 until November 2016, 4,356 CHPP-citizens will be randomized further to either
      intervention or control in the present trial: The intervention group receives an invitation
      which highlights the value of spirometry as part of a health check. The invitation is made in
      collaboration with the Danish Lung Association and has been tested on a focus group before
      the invitations are dispatched. The control group will receive a standard invitation. Primary
      outcome measure is effect on attendance. Secondary outcome is the percentage of participants
      with abnormal spirometry assessed at the preventive health check. The characteristics of the
      2 groups will be described according to sex, age, smoking history, spirometry values and lung
      symptoms. The intervention, the outcome and the group assignment in this trial are not
      revealed in the invitation for the citizens. Randomization is handled by an independent
      statistician.

      Sample size:

      The sample size is estimated to 4,356 participants in total and is calculated on the basis of
      the following assumptions: 1:1 randomization, two-sided significance level of 0.05, power of
      0.9, intracluster correlation coefficient of 0.01 and with an average of 1.5 citizens in each
      household, we calculated the design effect to be 1.05. Calculations are further based on the
      objective of being able to detect a difference of 5% in effect size of attendance. The
      investigators determined this 5% difference to be clinically meaningful based on expert
      opinions and criteria employed in other research. The intracluster correlation coefficient
      was included to reflect a possible clustering effect of the general practitioners (n = 46),
      which is seldom greater than 0.01 in primary care settings.

      Statistic analysis plan:

      -The main outcomes Effect of the intervention on attendance will be estimated by differences
      in the proportion of citizens attending the health check in each of the groups. Crude and
      adjusted estimates of the difference in proportion will be based on binominal regression.
      Also these estimates will be compared with estimates based on propensity scores.

      Furthermore, a descriptive analysis of attendees and non-attendees will be performed
      regarding sex, age, smoking history, self-reported lung symptoms and spirometry measurements.
      The analysis will follow the intention to treat principle.

      For each of the endpoints, the number and percentage of individuals experiencing the endpoint
      will be presented, by randomisation group. Binominal regression will be used to estimate the
      difference in proportion between the two groups, and 95% confidence interval, comparing the
      intervention group with the comparison group. The baseline measure of the outcome will be
      included as a covariate in the model. If the distribution of the outcome is skewed, a log
      transformation will be used.

      -Analysis of the baseline characteristics For the descriptive part of this study, bivariate
      and multivariate analysis will be performed. Continuous variables e.g. height and weight are
      presented as mean ± standard deviation, unless the variable has a highly skewed distribution,
      in which case, medians, 25th and 75th percentiles will be presented. For categorical
      variables, e.g. smoking status, civil status, and sex, the number and percentage of
      individuals within each category will be presented as absolute numbers and relative (%)
      frequencies. Anova will be used when comparing means or changes in means of numerical
      variables; and Chi2-test will be used when comparing proportions for categorical variables.
      Categorical outcomes will be analysed with logistic regression. The statistical significance
      level is set at p < 0.05. Statistical analysis will be performed using STATA 14.0 software.

      Prevention of missing data :

      The primary trial analysis will use an Intention To Treat (ITT) population, which includes
      all participants in the group to which they were randomised, regardless of the amount of
      intervention actually received. The only exclusion criterion is terminal illness as reported
      by the general practitioner.

      To prevent attendees refusing to participate, households are invited together and two
      reminders are sent out. Furthermore, appointments are scheduled outside of work hours.
      Finally, we have the unique opportunity to use the Danish registers as a population-based
      health care database with information about the non-attendees, described below.

      Treatment of missing data:

        -  Missing values due to incomplete clinical measurements or questionnaires Records with
           missing data due to incomplete questionnaires and incomplete spirometry measurements
           will be excluded. Sensitivity analysis will be performed and it will be considered if
           data are missing at random or not at random. Afterwards complete case analysis will be
           performed.

        -  Missing values of non-attendees As we have no clinical measurements or any answered
           questionnaires on the non-attendees, these data will be obtained from the Danish
           national registers. Sensitivity analysis will be performed and it will be considered if
           data are missing at random or not at random. Afterwards complete case analysis will be
           performed.

        -  Non-attendees will be described on following parameters:

             -  Sociodemographic: Education level, sex, age, ethnicity and civil status from 2016
                using Danish Civil Registration System(CRS)

             -  Socioeconomics: income and transfer payments from 2016 using the Danish Civil
                Registration System(CRS) .

             -  Contacts to their general practitioner from 2014-16 using reimbursement to the
                general practitioner from the Danish National Health Service Register.

             -  Prescriptions of respiratory medicine from 2014-16 using the information about
                redeemed medication from the Danish National Prescription Register by using the ATC
                group R03 from 1995-2013. We categorized the drugs into rescue drugs against airway
                symptoms e.g. SABA / SAMA and chronic drugs against airway symptoms e.g. SABA/
                SAMA, LABA/LAMA, leukotriene inhibitors, theophylline and inhaled corticosteroids.

      Hypothesis:

      The results from the present study are expected to contribute with important knowledge about
      the value of information on spirometry in invitations to health checks measured at different
      levels of attendance - as described above.

      Legal and ethical aspects:

      The study has been presented to The Scientific Ethics Committee and it is considered as
      routine data and thus ethical approval is not needed for the trial.

      The study will comply with the declaration of Helsinki and according to the Danish Health Law
      each of the participants will provide written informed consent for data to be used for
      research. Approval by The Danish Data Protection Agency is obtained (2014-54-0704).
    

Intervention name(s): focused information of spirometry in the invitation; standard invitation
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Focused information of spirometry in the invitation to the preventive health check compose the intervention in this trial.; The active comparator will receive a standard invitation to the preventive health checks. The preventive health checks in the active comparator group and the intervention group are identical.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Prevention