Elsevier

Sleep Medicine

Volume 10, Issue 9, October 2009, Pages 993-999
Sleep Medicine

Original Article
Psychological variables as predictors of adherence to treatment by continuous positive airway pressure

https://doi.org/10.1016/j.sleep.2009.01.007Get rights and content

Abstract

Study objectives

We examined whether psychological variables enable us to predict adherence to CPAP in order to construct a predictive model to identify patients at risk of abandoning treatment.

Method

One hundred and twenty-two Obstructive Sleep Apnoea (OSA) patients were studied before and one month after beginning CPAP treatment. All patients completed four psychological evaluation instruments before CPAP treatment: a health perception questionnaire (Nottingham Health Profile: NHP), a mental health rating scale (Hospital Anxiety and Depression Scale: HADS) and two disease-specific questionnaires that measure the patient’s understanding of OSA and its treatment (Apnea Knowledge Test: AKT) and his attitudes to OSA and CPAP (Apnea Beliefs Scale: ABS).

Results

Thirty percent of the participants were non-adherent at one month. Decision-tree analysis indicated that it was possible to correctly classify 85.7% of non-adherent patients using three baseline factors (Emotional reactions score [NHP], age, and total score on ABS). Logistic regression analyses confirmed these two psychological variables as independent predictors of adherence.

Conclusion

Assessing psychological well-being and subjective health status at onset of CPAP enables the identification of patients at risk of abandoning CPAP treatment. This subgroup could then be targeted early to receive supportive and educational measures to improve adherence rates.

Introduction

Obstructive sleep apnoea syndrome (OSAS) is a common condition [1] with symptoms of daytime somnolence, fatigue, irritability [2], depression and impaired cognitive function [3]. OSA is associated with high cardiovascular risks [4] and increased risk of road traffic accidents [5]. Continuous Positive Airway Pressure (CPAP) is an effective treatment for OSA, improving symptoms, reducing accidents and improving quality of life [6], [7].

Patients have variable responses and adaptations to CPAP treatment and thus require different medical and paramedical input. Some individuals find immediate improvement in symptoms and a renewed dynamism that makes acceptance of the treatment relatively easy [8]. However, if the patient has difficulty in accepting the diagnosis [9], suffers unpleasant side effects of the treatment, or experiences no obvious improvement in health status or quality of life, then there may be difficulties in adaptation to the treatment regime [10].

It would be useful if evaluations made at the point of diagnosis or at initiation of treatment could identify patients liable to have little problem with their CPAP or, in contrast, those who are likely to experience difficulties with adaptation. If patients could be stratified early on during their treatment, then strategies of adapted professional input could be applied to correct problems and use patient contact time to the greatest effect.

Apart from technical problems associated with the equipment, factors potentially influencing the level of CPAP compliance include measures of the initial severity of OSAS, such as the Respiratory Disturbance Index (RDI) or daytime somnolence at the time of diagnosis, as well as subjective improvement under treatment [11]. One factor affecting adherence to this demanding treatment is the level of involvement and education by healthcare professionals at the time of initiation of treatment [12]. Several studies have demonstrated improved adherence with increased patient-education input [13]. An important factor in the adherence to any long-term treatment is the beliefs the patient holds about his health, his illness and its treatment. These ideas, known in psychology as “health beliefs,” are thought to affect the patient’s “health behaviours” [14]. Health behaviours refer to the actions, habits and activities adopted by the patient, including his attempts to seek remedies for his illness and his willingness to adhere to medical advice.

The extent to which patients’ adaptation to treatment is influenced by psychological factors remains unclear. The idea that subjective health measures predict patient behaviours implies that psychological evaluations might aid in identifying the patients likely to be non-adherent.

The current investigation aimed to explore the beliefs and measure the subjective health of OSA patients embarking on CPAP treatment to see what factors influenced adherence levels with CPAP therapy. Specifically, we examined to what extent psychological variables help predict patient adherence to CPAP. These factors included quality of life and psychopathology, as well as patients’ understanding of and attitude to their illness and CPAP treatment.

Section snippets

Participants

All newly-diagnosed OSA patients were assessed, excepting those participating in other research protocols. The only exclusion criterion concerned the patients who were unable to answer the questionnaire. Polysomnography continuous recordings were taken with electrode positions C3/A2-C4/A1-Cz/01 of the international 10–20 Electrode Placement System, eye movements, chin electromyogram and ECG with modified V2 lead. Sleep was scored manually according to standard criteria [16]. Airflow was

Participants

One hundred twenty-two patients were recruited (Table 1), including 99 men. These patients suffered from sleepiness (mean Epworth Sleepiness Scale = 10.5 ± 5.3) with a mean age of 56 ± 11 yrs, mean Body Mass Index of 28.3 ± 4.4 kg/m2, mean nocturnal SpO2 of 94 ± 2.2% and mean RDI (Respiratory Disturbance Index) of 38.4 ± 19.9/h indicating moderate to severe sleep apnea. Two-thirds of the patients regularly used CPAP (⩾4 h/night) and one-third were non-adherent (<4 h/night). No significant differences were

Discussion

This study investigates the possibility of stratifying CPAP patients early in their experience of this demanding treatment. It is a preliminary study and our results help to identify the most useful variables extracted from these tools that could be applied in future tailored strategies for management of CPAP patients. If one could predict those patients who are most likely to have difficulty with CPAP, one could then develop individualised management strategies. To categorize the patients as

Acknowledgements

The authors thank COMARES (Comité des Maladies Respiratoires de l’Isère) and Agir à Dom for financial support for the study. They acknowledge the invaluable assistance of Philippe Roussel (Director of Agir à Dom, Grenoble) for his help in facilitating the data collection. They also thank the patients for accepting to participate in the study and the staff of the CPAP Department of Agir à Dom.

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