Subjects and Procedure
Inclusion criteria were as follows: outpatients coming to the hospital for pulmonary consultation, aged between 18 and 65 years, with asthma diagnosis made according to Global Initiative for Asthma guidelines at least 6 months before recruitment. Exclusion criteria were comorbidity (somatic and psychiatric diseases), non-Dutch speaking, brittle asthma, occupational asthma, and previous participation in an asthma education program. One of the researchers (V.L.) addressed the patients before their visit to the physician and invited them to take part in a study on participation in an asthma program. Patients gave their oral informed consent to receive information about the program and to be questioned about their opinion on the program. While showing the workbook used in the education sessions, we gave the patients a standard description of our asthma program:
We would like to invite you to an asthma program set up for patients with asthma who wish to learn more about their asthma, who wish to be more involved in their asthma treatment, or whose asthma is uncontrolled despite optimal treatment. By means of education, exercises, and interactive discussions, we teach participants ways to improve their self-care. The program takes place in the late afternoon over a period of one and a half months and includes 3 sessions: 2 group sessions of 2 hours and 1 individual session of 1 hour. Participation is free. We asked the participants to fill in questionaires at several fixed time points to evaluate the effects of the program.
We told the patients that they would be informed about the exact time and date of the sessions 3 weeks ahead of the program start. A structured interview, as described below, was administered to the patient. Subsequently, we handed questionnaires to the patients. These had to be filled in at home and sent back with a prestamped envelope to save time on the day of the study. We told the patients the interview and the questionnaires were meant to get a better understanding of their reasons to participate or not in our program. Finally, the patients indicated on a form their intention to participate. To avoid socially desirable answers, the researcher made sure respondents noted that she did not look at the answer they filled in on the form. This study was part of a larger effectiveness study of our asthma program and was approved by the local Ethical Committee.
Measures
The intention to participate in the program was measured as a desire to participate. Patients indicated with yes or no whether they wanted to participate. Patients who declined participation mentioned on the answering form the main reason for their decision.
Interview: A structured interview was set up to measure the proximal factors put forward in the ASE model (Appendix). When developing the interview, 15 pilot patients were probed for their beliefs about the program by means of open questions. The open questions addressed possible advantages of and barriers to participating. The answers were used to compose the final structured interview, consisting of 17 questions as described in the Appendix.
Of these, nine questions were developed to assess the patient’s attitude toward the program in terms of perceived benefits (1, 2, 5, 7, 11, 13, 14, 15, and 16); and seven questions assessing beliefs about barriers to participate were set up as a self-efficacy measure (3, 4, 6, 8, 9, 10, and 12). These 16 questions had an answering format on a 5-point Likert scale ranging from “I do not agree at all” (score = 1 for attitude questions; score = 5 for self-efficacy questions) to “I totally agree” (score = 5 for attitude questions; score = 1 for self-efficacy questions). A higher score reflects a more positive attitude. Self-efficacy scores were reversed for convenience sake; higher scores reflect fewer barriers and therefore higher self-efficacy.
The 17th and last section of the interview assessed social influence by asking 10 subquestions evaluating (1) social norms the patients experience to take better care of their asthma, such as “do(es) your partner/children/parents/best friend/others think you should take better care of your asthma?” (17A, 17B, 17C, 17D, and 17E); and (2) the patients’ motivation to comply with these social norms, such as “do you agree with him/her/them?” (17Ai, 17Bi, 17Ci, 17Di, and 17Ei). All 10 questions were answered with yes (score = 1) or no (score = 0). When the answer to questions 17A, 17B, 17C, 17D, or 17E was no (score = 0), the score stayed 0 no matter whether or not the patients were motivated to comply, because in that case no social influence was experienced to take better care of the asthma. When the answer to the questions 17A, 17B, 17C, 17D, or 17E was yes (score = 1), the score of the answer to the questions 17Ai, 17Bi, 17Ci, 17Di, or 17Ei was added. Thus, for every referent (partner, children), a minimum score of 0 and a maximum score of 2 could be obtained. Scores for the five referents were added to obtain a final social influence score, ranging from 0 to 10. All patients were required to find five referents who had an opinion on the way patients handled their asthma.
Questionnaires: Some additional issues were evaluated with the following questionnaires:
The McMaster Asthma Quality of Life Questionnaire: The McMaster Asthma Quality of Life Questionnaire (AQLQ) measures health-related limitations in quality of life experienced by patients with asthma during the past 2 weeks. Thirty-two items assess four domains: symptoms (12 items), emotions (5 items), exposure to environmental stimuli (4 items), and activity limitations (11 items), and have to be rated on a scale from 1 (low quality of life) to 7 (high quality of life).
The Asthma Symptom Checklist: The Asthma Symptom Checklist (ASC) is a 36-item questionnaire developed to assess subjective symptomatology in asthma. It consists of six symptom scales: symptoms of airway obstruction (five items), dyspnea (three items), fatigue (six items), anxiety (eight items), irritation (six items), and symptoms suggestive of hyperventilation (six items). The subjects rate on an 11-point scale the intensity with which they experienced a symptom the past 2 weeks (0 = no symptom, 10 = symptom as bad as possible).
The Knowledge, Attitude and Self-Efficacy Asthma Questionnaire: The Knowledge, Attitude and Self-Efficacy Asthma Questionnaire (KASE-AQ) consists of three subscales of 20-items each and assesses the following: (1) patients’ knowledge regarding asthma (every item rated 0 or 1, total scores ranging from 0 to 20); (2) patients’ attitude toward the illness; and (3) self-efficacy regarding the perceived ability to control the disorder (every item rated on a 5-point scale, total scores ranging from 20 to 100 per subscale).
The Positive and Negative Affect Schedule: The Positive and Negative Affect Schedule (PANAS) consists of two subscales (10 items per scale), assessing positive and negative affectivity as a personality trait. On a list of 20 adjectives (eg, sad, enthusiastic, nervous), the subjects indicate the degree to which the adjective is applicable to him/her, from “very little or not at all” (score = 1) to “very much” (score = 5).
In addition to the questionnaires, the highest level of education obtained and marital status were questioned.
Clinical Characteristics: The following clinical characteristics were collected from the medical files: pulmonary function performed on the day of the visit: FEV1, FVC, peak expiratory flow (PEF), number of years with asthma, and previous hospitalizations due to an asthma exacerbation (0 = none, 1 = one or more hospitalizations in the past).
Statistical Analysis
Statistical analyses were performed on data obtained from the 107 patients who returned the questionnaires. Missing values in the questionnaire data were replaced by individual scale means when at least 50% of the scale items were filled in, to guarantee representative results. All statistical analysis was performed after the distributions had been checked for normality. A principal component analysis with varimax rotation was performed on the attitude, self-efficacy, and social influence interview questions to evaluate their psychometric characteristics.
Group means of the questionnaire data assessed in the participant and nonparticipant groups were compared with one-way analysis of variance tests, x2 tests, or Mann-Whitney U tests when appropriate. The characteristics that were significantly different in the two groups were included in the regression model as distal factors.
We performed a series of logistic regressions on the distal and proximal factors included in the model and evaluated the predictive power of the factors on the intention to participate in the program. Statistical analyses were computed with the statistical program (SPSS version 11.0; SPSS; Chicago, IL).