Behaviours predicting CPAP adherence in OSA: a modelling analysis
Research type
Research Study
Full title
Early behaviour predicting adherence to Continuous Positive Airway Pressure therapy in patients with Obstructive Sleep Apnoea: a growth mixture modelling analysis
IRAS ID
321680
Contact name
S. Amanda Sathyapala
Contact email
Sponsor organisation
Imperial College London
Duration of Study in the UK
1 years, 2 months, 29 days
Research summary
It has been reported that non-adherence to Continuous Positive Airway Pressure (CPAP) in patients with Obstructive Sleep Apnoea (OSA) is high from trials but data from patients in clinical services is lacking because the studies have been flawed. We collected data from five UK sleep centres demonstrating that 66% of patients were not adherent to CPAP in 2019 (defined as a minimum of four hours a night for at least 70% of nights) and this figure was not significantly different at 58% (range 49-71%) in 2020, just three months after starting treatment. This a major issue because patients who are not adherent to CPAP are effectively untreated, continuing to experience symptoms of sleepiness, tiredness, poor concentration, memory, depression and anxiety and the significantly increased risk of heart attacks, strokes, type 2 diabetes, high blood pressure, and death. It is also a major problem for health services as CPAP is not cost-effective for the NHS to provide (at £20,000 per quality-adjusted life year) unless used for one year and CPAP non-adherence at current levels would be costing the economy around 147 million yearly.
CPAP adherence and non-adherence have also been reported to develop from treatment onset but studies have included less than 150 patients. When we plotted our data from 1000 patients, this appears to contradict these early studies with patients appearing to fall into at least four groups with two changing their CPAP use in the early period e.g having good use that falls or low use that increases. To identify these patterns are genuinely different, we would need to perform statistical modelling and regression, which is what we are requesting to do in this study. If we confirm these behaviours are distinct, practice can be changed so tailored support is given according to behaviour which should improve CPAP adherence.
Lay summary of study results: Background There are high rates of poor usage (non-adherence) to continuous positive airway pressure (CPAP), which is first line therapy, patients in obstructive sleep apnoea. The result is poor outcomes for these patients. There are a lack of studies investigating behaviours that may help understand non-adherence and help treat it.
Methods: We conducted a special form of statistics (growth mixture modelling (GMM)) on data already collected from 1000 patients at 5 UK sleep centres over the first three months of their treatment. Patients were defined as being adherent to treatment according to accepted criteria -if their mean CPAP-usage was ≥4 hours/night for ≥70% of nights.
Results: GMM identified six distinct CPAP-usage behaviour patterns over month 1. In four (54% of patients), CPAP-usage increased or decreased, in two (remaining 46%), CPAP-usage/non-usage was consistent. 62% of the cohort were non-adherent by Month 3, despite pathways following current recommendations for gold-standard practice. 98% of patients who were non-adherent by month 3 were already non-adherent by month 1. We completed a separate regression analysis with a separate dataset demonstrated that early CPAP-usage behaviour explained the majority of variation between patients' CPAP use (86% of the variance) at month 3 meaning that these CPAP usage behaviours were meaningful and important to identify.
Conclusions: These data, supported by previous work, indicate that current recommendations of follow-up at day 30-90 are too late to prevent CPAP non-adherence. Determining CPAP-usage behavioural pattern in week 2 identifies risk of CPAP non-adherence at month 3 and permits the possibility of interventions tailored to usage pattern.
REC name
London - Queen Square Research Ethics Committee
REC reference
23/LO/0142
Date of REC Opinion
28 Feb 2023
REC opinion
Favourable Opinion