Impact of CPAP on cardiac endpoints in OSA

Prof. Anita Simonds (National Heart & Lung Institute, UK) critically reviewed the available data on the link between continuous positive airway pressure (CPAP) therapy and cardiovascular outcomes in patients with obstructive sleep apnoea (OSA). Also, she painted a picture of how to synchronise randomised-controlled trial (RCT) data with clinical practice.

Evidence from RCTs

Nocturnal heart rate changes, sleep arousal burden, hypoxic burden, total sleep time with oxygen saturation <90%, and duration of obstructive events are established risk factors for cardiovascular diseases (CVD) in patients with OSA [1]. “But what is the impact of CPAP therapy on cardiac outcomes in these patients?” asked Prof. Simonds. To answer this question, she discussed data from important trials that investigated the use of CPAP for the secondary prevention of CVD in patients with OSA [2].

The SAVE trial (NCT00738179) randomised 2,717 patients with OSA and prevalent CVD to CPAP therapy or the control group. After a follow-up of 43 months, there was no benefit for the participants who had received CPAP compared with those who had not received this therapy (HR 1.10; 95% CI 0.91­–1.32). However, there was an effect for participants who had a higher adherence to CPAP therapy (>4 hours per night; HR 0.52; 95% CI 0.30–0.90) [3]. Interestingly, the RICCADSA trial (NCT00519597) and the ISAACC trial (NCT01335087) demonstrated a similar pattern: participants with a better adherence to CPAP therapy appeared to have a benefit in terms of cardiovascular outcomes [4,5]. “Thus, the consensus from clinical trials is that the use of CPAP is not associated with a reduction in cardiovascular events, except for patients who use CPAP therapy >4 hours per night,” summarised Prof. Simonds.

The way forward

“This is however not the end of the story,” commented Prof. Simonds. A post-hoc analysis of the SAVE trial demonstrated that participants with cerebrovascular disease and diabetes mellitus were more likely to benefit from CPAP therapy in terms of stroke reduction than participants with cerebrovascular disease alone, participants with CVD and diabetes mellitus, or participants with CVD alone [6]. Also, younger participants, participants with greater desaturation, or participants with increased obesity were more likely to achieve cardiovascular benefits from CPAP therapy [7]. “These results indicate that phenotyping and clustering is important,” stressed Prof. Simonds.

Next, it has been shown that hypoxic burden and T90 are more closely linked to cardiovascular outcomes than the apnoea hypopnoea index (AHI) or the oxygen desaturation index (ODI), notwithstanding that these last 2 measures have been used to stratify participants in clinical trials [8]. Furthermore, less than 20% of the patients in the clinic meet the criteria for randomised-controlled trials, displaying a large discrepancy between trial results and clinical practice [9]. “Therefore, we need to incorporate new evidence, preferably real-world evidence,” argued Prof. Simonds. “These studies should also include more women and patients from various ethnic backgrounds and report on patient-related outcome measures. In this way, we can start to synchronise the results from randomised clinical trials with everyday clinical practice.”

1. Yasir M, et al. Front Neurol. 2022;13:801167.
2. Simonds AK. Appraisal and critical review of the effects of PAP treatment on cardiovascular endpoints. Session 407, Abstract 3634, ERS International Congress 2022, Barcelona, Spain, 4–6 September.
3. McEvoy RD, et al. N Engl J Med. 2016;375:919–931.
4. Peker Y, et al. Am J Respir Crit Care Med. 2016;194(5):613–620.
5. Sánchez-de-la-Torre M, et al. Lancet Respir Med. 2020;8(4):359–367.
6. Quan W, et al. EClinical Med. 2018;2-3:59–65.
7. Xu P-H, et al. Thorax. 2022:217714. DOI: 10.1136/thoraxjnl-2021-217714.
8. Trzepizur W, et al. Am J Respir Crit Care Med. 2022;205(1):108–117.
9. Reynor A, et al. Sleep. 2022;45(4):zsab264.

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Posted on 30 October, 202220 February, 2024