TABLE 1.
Factors potentially associated with the appropriate use of asthma drugs
| Independent variable | Brief description | |
|---|---|---|
|
Predisposing factors | ||
| Age | Date of interview – date of birth; dummy coded (age [years] younger than 20, 20 to 29, or 30 and older) | |
| Sex | Confirmed at interview | |
| Educational level* | Highest completed educational level. Two categories (none, elementary school or high school not completed; high school completed, college or university) | |
| Main occupation* | Two categories (student/worker or other) | |
| Family income* | Low, high or undetermined (defined as low for family with 1 or 2 persons if below $30,000/year, for family with 3 to 4 persons if below $40,000/year, or for family with 5 or more persons if below $60,000/year) | |
| Body mass index (BMI) | Height and weight were asked of participants. BMI calculated by dividing weight in kg by height in metres squared, then dummy coded using WHO categories (28) (24.9 kg/m2 or less, 25.0 kg/m2 to 29.9 kg/m2 or 30 kg/m2 or higher) for individuals 18 to 45 years of age and using CDC BMI charts (29) for individuals 12 to 17 years of age | |
| Perception of health* | Measured by a 5-item question, range: poor to excellent, and then dichotomized (fair or poor; good, very good or excellent) | |
| Perception of asthma severity | Measured by a 5-item question, range: very mild to very severe, and then dichotomized (moderate, severe or very severe; very mild or mild). | |
| Beliefs about asthma† | Six yes/no questions. Number of positive answers per participant computed. Participants then dichotomized using median as cut-off point‡ (median = 4) | |
| Attitudes towards asthma† | Nine yes/no questions. Number of positive answers per participant computed. Participants then dichotomized using median as cut-off point‡ (median = 7) | |
| Self-confidence | Two yes/no questions referring to confidence in personal ability to contribute to the management of illness. Number of positive answers per participant computed. Participants then dichotomized using median as cut-off point§ (median = 2) | |
| Knowledge about: | Scores computed adding 1 point for each good answer. Missing values and “I don’t know” answers coded as incorrect answer. Each variable then dichotomized using median as cut-off point | |
| Asthma physiopathology | Three true/false questions§ (median = 3) | |
| Asthma symptoms | Two true/false questions§ (median = 2) | |
| Asthma triggers | Three true/false questions‡ (median = 2) | |
| Asthma self-management | Six true/false questions‡ (median = 4) | |
| Knowledge about asthma drugs | Four true/false questions for each drug mentioned by participant. Knowledge score for each drug computed on scale of 0 to 4, with 4 a perfect score. A mean asthma drug(s) knowledge score computed for each participant. Participants subsequently dichotomized according to said score using median as cut-off point‡ (median = 2.67) | |
| Number of years with asthma | Age at the interview – age (years) at first diagnosis of asthma; continuous | |
|
Enabling factors | ||
| Perceived effects of treatment | Perception of drug efficacy measured for each drug mentioned by participants using a 4-item question (no effect to a lot of effect). Dichotomized by grouping together those individuals who answered “a lot of effect” for all their drugs | |
| Perception of risk of dying due to asthma if drug is taken as directed by physician | Assessed for each drug mentioned by participant using a 4-item question (range: no risk to very high risk). Dichotomized by grouping individuals who answered “no risk” for all of their drugs | |
| Perception of risk of dying due to asthma if drug is not taken as directed by physician | Assessed for each drug mentioned by participant using a 4-item question (range: no risk to very high risk). Dichotomized by grouping individuals who responded “moderate risk”, “high risk” or “very high risk” for all of their drugs | |
| Self-reported side effects | Assessed for each drug mentioned by participant (yes/no). Dichotomized by grouping individuals not reporting adverse effects for any drugs | |
| Short of drugs due to a lack of money | For each drug mentioned by participant assessed by a yes/no question, as to whether they had been short of drug during preceding year due to a lack of money. Dichotomized by grouping individuals who responded “no” for all of their drugs | |
| Ease in obtaining appointments with physicians | Individuals reporting an appointment with a physician during preceding year asked about ease in obtaining same (4-item question, range: very difficult to very easy), then dichotomized (very easy/easy; difficult, very difficult or physician not seen during preceding year) | |
| Ease in obtaining information on asthma from : | Each item assessed as follows: individuals reporting having seen a health professional the preceding year were asked about ease in obtaining information on asthma from said professional (4-item question, range: very difficult to very easy) and then dichotomized (very easy/easy; very difficult, difficult or professional not seen during preceding year) | |
| Pharmacist | ||
| Nurse | ||
| Respiratory therapist | ||
| Other health professionals | ||
| Possession of a written action plan | Assessed using 5 yes/no questions: ever received written instructions from a physician, nurse, pharmacist, respiratory therapist or other health professional? Dichotomized by grouping those responding “yes” to any of these questions | |
| Daily or weekly use of peak flow meter | Two questions: Participant uses a peak flow meter (yes/no). If “yes”, participant assessed for peak flow meter use: every day/approximately once a week/once a month/less than once a month. Dichotomized by grouping individuals responding “yes” to the first question and “every day” or “approximately once a week” to the second question | |
| Vaccination against influenza in past 12 months | One yes/no question | |
| Vaccination against pneumonia in past 12 months | One yes/no question | |
| Ever tested for allergies | One yes/no question | |
| Lung function test | Two questions: Did you have a lung function test during the past 12 months? (yes/no). If “no”, assessed for ever having lung function test (yes/no). Dichotomized by grouping those responding “yes” to either question | |
| Ever obtained written information on asthma from health professionals | Five yes/no questions: Have you ever received written information on asthma from: a physician, a nurse, a pharmacist, a respiratory therapist or other health professional? Dichotomized by grouping individuals responding “yes” to any question | |
| Ever had inhalation technique verified by health professional | Five yes/no questions: Has your inhalation technique ever been checked by: a physician, a nurse, a pharmacist, a respiratory therapist or other health professional? Dichotomized by grouping individuals responding “yes” to any question | |
| Attended an asthma education clinic | Three yes/no questions: At any time last year, did a doctor or other health professional suggest you meet with an asthma educator? If yes, did you do so? At any time in the past year did you attend an asthma education clinic run by a doctor or other health professional? Dichotomized by grouping individuals responding “yes” to the first two questions or “yes” to the third | |
| Consulted general practitioner during preceding year for asthma-related problems | Two questions: During the past year, did you consult a physician about your asthma or an asthma-related problem, in a clinic, at a CLSC¶, at an emergency room or during a hospitalization? If answer “yes”, physician type assessed using 3-item question (general practitioner, specialist or both). Participants responding “yes” to first question and “general practitioner” or “both” to second question, were considered to have consulted a general practitioner during the previous year for asthma-related problems | |
| Consulted specialist during the preceding year for asthma-related problems | Two questions: During the past year, did you consult a physician about your asthma or an asthma-related problem, in a clinic, a CLSC¶, at an emergency room or during a hospitalization? If answer “yes”, physician-type assessed using 3-item question (general practitioner, specialist or both types of physician). Participants responding “yes” to first question and “specialist” or “both types of physicians” to second question, were considered to have consulted a specialist during the previous year for asthma-related problems | |
|
Reinforcing factors | ||
| Coherence of information | Coherence of the information provided by health professionals measured by two yes/no questions: Do health professionals seem to agree about your asthma treatment? Do health professionals seem to agree about things to do concerning your asthma? “Yes” answer to both questions considered to be coherence | |
| Satisfaction with physician care | Two 4-item questions on satisfaction with information given by physician and satisfaction with attention given by physician, range: very satisfied to very dissatisfied. Participants answering “satisfied” or “very satisfied” to both questions were considered satisfied with their patient-physician relationship | |
| Social support | Perceived social support measured using 6 questions. Score constructed and discrete version of the variable composed using median as cut-off point‡ (median = 5) | |
*
Questions used in 1998 in l’Enquête de Santé Québec sur les habitudes de vie et la santé des québécois (an enquiry into lifestyle and health of Quebec residents);
†
Questions that are usually the object of interventions in asthma education clinics;
‡
The median value was put in the lower group;
§
The median value was put in the higher group;
¶
A provincially run local community centre offering basic primary health care and social services of preventive or curative nature and rehabilitation or integration services to the population it serves. CDC Centers for Disease Control and Prevention