Design
A multi-centre randomized, controlled trial (RCT) design was used, enrolling adult patients with OSA and a prescription for CPAP treatment from the Respiratory Medicine Department at La Princesa University Hospital (Madrid, Spain), Joan XXIII University Hospital (Tarragona, Spain) and Central University Hospital of Asturias (Oviedo, Spain), between May 2018 and June 2019. The study protocol was approved by the Clinical Research Ethics Committee at the participating hospitals (N. 3450; N96/19). The clinical trial was registered with www.clinicaltrials.gov (NCT 04691479).
Patients
The subjects enrolled in the study were required to have a diagnosis of OSA confirmed by sleep studies with polygraphy and/or polysomnography (criteria of the Spanish Sleep Society) and be naive to CPAP intervention. The study excluded subjects with obesity-related hypoventilation, severe COPD, cognitive disorders and those unable to understand the consent to participate. Prior to enrolment in the study, all patients were informed in detail about the study and signed the consent form to participate.
Interventions
A process was followed using a random number generator in SPSS to systematically assign patients to one group or another, with allocation concealment. Prescribers were responsible for randomization. See Fig. 1.
The control intervention group patients followed the standard of care. The therapy started in the hospital. The nurse performed training in the use of CPAP equipment, mask adjustment, safety, and maintenance. For follow-up, the patient was always referred to the Hospital, with a frequency established by the Spanish Society of Pulmonology and Thoracic Surgery (Days 30, 90 and 180). The follow-up procedure consisted of reviewing the CPAP hour-meter and resolving any, with the necessary corrective actions.
The intervention group ‘PIMA’ (Spanish acronym: Plan Individualizado de Mejora de la Adherencia; Personalized Adherence Improvement Plan), began the treatment with the educational and training program “MEntA” (Motivational Interview for Adherence) [12]. It consisted of one session with two blocks: educational activity and training activity. Also, the key to all patient interactions was the use of MI. In fact, the nurse used MI not only at the beginning of therapy, but also in every contact that the patient had with the patient throughout the treatment (subsequent follow-up visits, phone calls, etc.).
Subsequently, the nurse performed the stratification process, which determined the personalized intervention plan using two types of variables: personal and modulation. The variables of the stratification established the complexity and intensity of adaptations for the patient's treatment needs. Personal variables consider characteristics of the patient such as: age, level of studies, clinical (somnolence and apnoea-hypopnea index), and psychological (motivation and perceived competence). Modulation variables refer to characteristics ranging from the patient's environment (isochrone, which is the time the patient spends from home to the care center) to service options and preferences (for example, use of electronic applications, email, or visit preferences). The results are patients with the "a" profile (characterized by autonomy and mobility, predisposition to remote-controlled follow-up), patients with the “b” profile (need for more intensity in follow-up), or patients with the "c" profile (more difficulties to move around and require more intensive treatment). Profile "d" was applied to patients who were professional drivers, as they require specific interventions based on their occupation.
Regarding psychological variables for the evaluation of perceived competence, the Perceived Competence Evaluation Questionnaire validated in Adherence to CPAP in OSA (CEPCA) was used [13]. The scores obtained indicated the patient’s feelings for self-effectiveness with the CPAP treatment. Motivation was also assessed, using the methodology defined in the Prochaska and DiClemente transtheoretical model [14], with an open-ended question to the patient which could be classified in five stages: precontemplation (very low motivation), contemplation (low motivation), determination (some motivation), active change (quite motivated) and maintenance (high motivation). Regarding the clinical variables, drowsiness was obtained through the administration of the Epworth Somnolence Test [15], and the apnoea-hypopnea index was taken from the patient's clinical history.
The personal and modulating variables were used to identify the degree of intensity the patient needed (channels and frequency of contact). The psychological and clinical variables obtained in this first visit were used as "predictive" information for patient adherence (either high, moderate or low). Subsequently, the care plan was initiated based on this information. Low or moderate adherence care plans were more intensive than high adherence relative care plans. In Table 1 we can see how the patient's profile (a, b, c or d) and the level of adherence determine the care plan.
Table 1
PIMA Care Plans: profile, level of adherence and general interventions
|
Profile
|
High Adherence
|
Moderate Adherence
|
Low Adherence
|
|
a
|
Channels: Phone-call
Frequencies:
-90 days: moderate
-after 90 days: low
Contents: Positive motivational reinforcement
|
Channels: Phone-call & Care Center
Frequencies:
-90 days: intensive
-after 90 days: moderate
Contents: Motivational interview, functional analysis
|
Channels: Phone-call & Care Center
Frequencies: Intensive
Contents: Motivational interview, training and educational reinforcement
Telemonitoring
|
|
b
|
Channels: Phone-call & Care Center
Frequencies:
-90 days: moderate
-after 90 days: low
Contents: Positive motivational reinforcement
|
Channels: Care Center
Frequencies:
-90 days: intensive
-after 90 days: moderate
Contents: Motivational interview, functional analysis
|
Channels: Care Center
Frequencies: Intensive
Contents: Motivational interview, training and educational reinforcement
Telemonitoring
|
|
c
|
Channels: Home
Frequencies:
-90 days: moderate
-after 90 days: low
Contents: Positive motivational reinforcement
|
Channels: Home
Frequencies:
-90 days: intensive
-after 90 days: moderate
Contents: Motivational interview, functional analysis
|
Channels: Home
Frequencies: Intensive
Contents: Motivational interview, training and educational reinforcement
Telemonitoring
|
|
d
|
Channels: Phone-call
Frequencies:
-90 days: moderate
-after 90 days: low
Contents: Positive motivational reinforcement
Telemonitoring
|
Channels: Phone-call & Care Center
Frequencies:
-90 days: intensive
-after 90 days: moderate
Contents: Motivational interview, functional analysis
Telemonitoring
|
Channels: Care Center & Home
Frequencies: Intensive
Contents: Motivational interview, training and educational reinforcement
Telemonitoring
|
In follow-up visits, psychological and clinical variables were reviewed and the patient's adherence was added (the profile always remains the same, since their personal characteristics are generally stable). Based on the level of adherence, the care plan was adapted if the patient’s situation had changed. For patients with low adherence, telemonitoring was used to measure hours of adherence, AHI and air leaks. Once the follow-up procedure with telemonitoring of 1 month had started, every 10 days, the patient evolution was reviewed. The level of adherence determine the frequencies of interventions, taking into account short term (first 90 days of treatment) and after day 90. This configuration allows, on the one hand, the dedication of resources to patients who need more care, and on the other hand, the long-term management of large volumes of patients.
Several outcomes were included in this study. First, adherence to CPAP therapy after 90, 180 and 365 days of treatment was assessed as the primary outcome. The total number of night-time hours during which the CPAP device was used at a therapeutic pressure was recorded by specific counters within each device and were collected during the study follow-up period. In terms of secondary outcomes, quality of life was assessed using the Visual Analogical Well-being Scale for apnoea [16] and sleepiness was assessed using the Epworth Sleepiness Scale [15]. Motivation was also assessed, as defined in the transtheoretical model [14] using an open-ended question to the patient, which could be classified in the five stages. Moreover, three health related outcomes (mood, activities, social relationships) were also measured using the following ad hoc question "Taking into account your sleep problems, how would you say you are in terms of mood/activities/social relationships?". The answer alternatives were: Good, Normal/no change, Bad.
Statistical analysis
The sample size was determined based on a previous moderate effect size of .06 because there was no prior literature available with similar characteristics to those proposed in this study. As such, with an alpha value of .05 and a maximum beta error of .20, a total number of 70 subjects were established, which was increased considerably in order to compensate for possible experimental mortality in the study and to reduce the variability of the measures being studied.
Statistical analysis is based on intent-to-treat (ITT) analysis of the participants. A descriptive analysis of the demographic and clinical characteristics of all patients enrolled in the study was performed, as well as a baseline analysis comparing both study groups after randomization. The statistical inference analyses were performed using both parametric (t-student for independent groups) and non-parametric (U-Mann Whitney) models for continuous variables, and crosstab analysis for categorical data. The analyses were performed for the comparison of study groups at two cut-off time points (90 and 180 days) and an ad hoc analysis at one year of follow-up for the most important variables. The Chi-square statistic was used for comparing all categories at one year adherence analysis. The alpha value was 0.05 and all analyses were performed on two-tails. The statistical software used was SPSS V26.