Rethinking Sleep Apnea: Dr. Atul Malhotra on Remote Patient Monitoring, Central Apnea, and the Future of GLP-1 Therapy
Dr. Atul Malhotra discusses why one night of sleep testing can miss night-to-night variability, and what multi-night monitoring adds for central sleep apnea (CSA), hypoxic burden, and GLP-1 therapy.
Why isn’t one night of sleep testing enough?
Dr. Malhotra warns that “single-night polysomnography gives you a snapshot, nothing more.” Sleep varies from night to night due to factors like body position, REM cycles, alcohol intake, or even minor illnesses such as colds. Such variability can lead to significant misclassification. For example, a recent study in Sleep observed night-to-night AHI variability of ≥10 events/hour in over one-third of adults, driven by variations in REM sleep and posture. Large-scale home testing has shown that relying on only the first night misclassifies moderate OSA in about 20% of cases, disproportionately affecting women and REM-predominant OSA patients.
Further, in a separate cohort of more than 12,000 adults monitored over hundreds of nights, individuals with high night-to-night AHI variability exhibited a 50 to 70% higher risk of uncontrolled hypertension, regardless of their average AHI. RPM (by enabling repeated measurements over multiple nights) offers a more accurate assessment of OSA severity and associated vascular risk, reducing the chance of false negatives or inappropriate treatment initiation.
What does “hypoxic burden” mean, and why is it important?
“The AHI is the best we have, but it’s nowhere near perfect,” Dr. Malhotra observes, noting that two patients may show identical event counts yet differ in the depth and duration of hypoxic episodes, arousal frequency, and cardiovascular risk. Metrics like hypoxic burden, which integrates the duration and severity of oxygen desaturations, have demonstrated stronger predictive power for cardiovascular outcomes than AHI alone. Analyses from the Sleep Heart Health and MrOS cohorts showed that higher hypoxic burden independently predicted heart failure risk, with each incremental increase associated with a 45% higher incidence. Since AHI does not capture these dimensions, RPM systems that routinely track hypoxic burden can improve risk stratification and support more targeted interventions.
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How should clinicians evaluate a home sleep testing device?
Dr. Malhotra cautions against overvaluing the number of channels in a home sleep testing device, emphasizing instead the importance of validating against in-lab polysomnography. Many RPM systems use PPG or oximetry, and pulse oximeters have been found to overestimate oxygen saturation in individuals with darker skin, as reported in a 2024 Duke cohort study of critically ill patients. In January 2025, the FDA issued draft guidance recommending that pulse oximeters be validated across different skin tones. Devices with airflow and respiratory effort channels add direct respiratory measurements, which are particularly useful for detecting central apnea. Wesper Lab measures airflow and respiratory effort directly, with two wearable patches on the chest and abdomen and no nasal cannula.
What is Central Sleep Apnea (CSA), and how is it different from Obstructive Sleep Apnea (OSA)?
“If you miss central sleep apnea, you may pick the wrong treatment,” Dr. Malhotra warns, and some patients feel worse on CPAP. Central sleep apnea (CSA) is prevalent among patients with systolic heart failure (affecting up to 40%) and if left untreated, elevated sympathetic tone can exacerbate cardiac dysfunction. Phrenic-nerve stimulation has emerged as a promising therapy: clinical trials demonstrate a halving of AHI and improvements in heart rate variability and sleep architecture over 3 to 12 months. Adaptive servo-ventilation (ASV), once labeled unsafe following SERVE-HF, has been shown to be neutral in cardiovascular outcomes in more recent trials such as ADVENT-HF. RPM systems with airflow and effort channels can help clinicians screen for CSA and guide patients toward appropriate (often non-CPAP) treatments.
How do GLP-1 medications like tirzepatide affect sleep apnea?
Dr. Malhotra highlights a major shift: “Tirzepatide cut AHI almost two-thirds in the SURMOUNT‑OSA trials. But as patients lose weight, their physiology moves, so you need RPM at every major milestone.” The 52-week SURMOUNT-OSA Phase III trials in NEJM showed ≥20 events/hour reductions in AHI with tirzepatide versus ~5 events/hour reduction with placebo. Moreover, there were marked improvements in hypoxic burden, systolic blood pressure, inflammatory markers, and patient-reported outcomes. The FDA’s December 2024 approval of Zepbound (tirzepatide) for moderate-to-severe OSA in adults with obesity further confirms its clinical relevance. Since weight loss alters upper airway dynamics, scheduled RPM at baseline, 3 months, and after each 10% weight loss increment helps re-evaluate disease severity, adjust PAP settings, and detect emergent CSA.
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Integrating RPM with Wesper
| Feature | Supported By |
|---|---|
|
AHI variability and hypertension risk |
|
Mortality/CVD prediction |
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Direct respiratory data, including central events |
|
Guides phrenic-nerve stimulation/ASV |
|
Tracks physiology during weight loss |
Wesper Lab is worn as two patches on the chest and abdomen and captures positional variability, respiratory effort, SpO2, and hypoxic burden over multiple nights. This at-home, multi-night data collection lets clinicians see how a patient’s results change from night to night, a pattern described in sources 1 and 2 below. Hypoxic burden, which the Wesper portal reports alongside AHI and ODI, has been shown in a published cohort study to predict cardiovascular mortality (source 3). For CSA, the airflow and effort channels let clinicians review central events when choosing between treatments such as phrenic-nerve stimulation and ASV. For patients on GLP-1 therapy, serial testing tracks physiologic changes during weight loss, so therapy can be adjusted at each milestone.
Dr. Malhotra’s takeaway is that tailored, dynamic care, enabled by platforms like Wesper, can improve outcomes.
Frequently Asked Questions (FAQ)
Why isn’t one night of sleep testing enough?
A single-night study can be misleading due to natural fluctuations in sleep patterns caused by posture, REM cycles, environmental factors, and illness. Research has shown significant variability in AHI scores from night to night, which can lead to misdiagnosis or inappropriate treatment plans. Multi-night testing helps create a more reliable average and reduces the risk of false negatives.
What does “hypoxic burden” mean, and why is it important?
Hypoxic burden measures the total amount of oxygen desaturation during sleep. Unlike AHI, which counts breathing interruptions, hypoxic burden accounts for the depth and duration of desaturations. It has been shown to be a stronger predictor of cardiovascular outcomes than AHI alone.
What does Wesper Lab measure?
Wesper Lab is worn as two patches on the chest and abdomen, with no nasal cannula. It measures airflow, thoracic and abdominal effort, body position, SpO2, heart rate, and sleep staging, and multi-night testing comes standard. Wesper devices show over 95% AHI correlation to in-lab PSG (Sleep Medicine 2025; JCSM 2023).
What is Central Sleep Apnea (CSA), and how is it different from Obstructive Sleep Apnea (OSA)?
CSA occurs when the brain temporarily stops sending signals to the muscles that control breathing, as opposed to OSA, where the airway becomes physically blocked. CSA is common in patients with heart failure, opioid use, or stroke, and requires a different treatment strategy. CPAP may not be effective or could worsen symptoms in CSA patients.
What treatments are available for CSA?
CSA can be treated with adaptive servo-ventilation (ASV), phrenic-nerve stimulation, and in some cases, medications that influence respiratory drive. Phrenic-nerve stimulation has shown promise in improving sleep architecture and reducing cardiovascular risk. Wesper Lab measures airflow and respiratory effort, which lets clinicians review central events when planning treatment.
How do GLP-1 medications like tirzepatide affect sleep apnea?
GLP-1 medications lead to significant weight loss, which can reduce or even resolve OSA in some patients. In the SURMOUNT-OSA trials, tirzepatide reduced AHI by up to 63%. However, as patients lose weight, their sleep patterns and physiology shift, so serial monitoring can help guide therapy changes.
When should sleep be retested during GLP-1 therapy?
Dr. Malhotra recommends retesting at baseline, after 3 months, and at each 10% body weight milestone. This ensures therapy is adjusted as the patient's physiology evolves. Wesper supports this with wearable, multi-night, longitudinal monitoring.
Is Wesper suitable for patients on CPAP or other non-PAP therapies?
Yes. Wesper's multi-night data collection allows clinicians to evaluate how well a treatment is working and make adjustments over time. It also helps detect residual events or emerging issues, such as central apneas, that may not have been present during initial diagnosis.
Why is racial equity an issue in sleep diagnostics?
Pulse oximeters have been shown to overestimate oxygen levels in people with darker skin tones, as reported in a 2024 study of critically ill patients. This can lead to underdiagnosis of sleep apnea. In January 2025, the FDA issued draft guidance recommending that pulse oximeters be validated across skin tones.
How can I integrate Wesper into my sleep practice?
Wesper is designed to fit into both primary care and specialist workflows. A medical provider orders the test, and the portal offers automatic scoring and full access to raw data for clinician review, with easy setup and ongoing support for patients.
Sources
- Hynes DJ, et al. Night-to-night variability in obstructive sleep apnea severity. Sleep. 2025. pubmed.ncbi.nlm.nih.gov
- Punjabi NM, et al. Variability and Misclassification of Sleep Apnea Severity Based on Multi-Night Testing. Chest. 2020. pmc.ncbi.nlm.nih.gov
- Azarbarzin A, et al. Hypoxic burden predicts cardiovascular mortality. Eur Heart J. 2019. pubmed.ncbi.nlm.nih.gov
- Hao S, et al. Utility of Skin Tone on Pulse Oximetry in Critically Ill Patients. Crit Care Explor. 2024. pmc.ncbi.nlm.nih.gov
- U.S. FDA. Draft Guidance on Pulse-Oximeter Performance Across Skin Tones. Press release, 6 Jan 2025. fda.gov
- Hodossy K, et al. Central Sleep Apnea Syndrome in Chronic Heart Failure. Cardiol Rev. 2023. pubmed.ncbi.nlm.nih.gov
- Costanzo MR, et al. Phrenic-Nerve Stimulation for Central Sleep Apnea. Eur J Heart Fail. 2018. pubmed.ncbi.nlm.nih.gov
- Perger E, et al. ADVENT-HF: Adaptive Servo-Ventilation in Heart Failure: Outcome Analysis. J Card Fail. 2024. pubmed.ncbi.nlm.nih.gov
- Eli Lilly & Co. Tirzepatide Reduced OSA Severity by up to 62.8 % in SURMOUNT-OSA. Press release, 2024. prnewswire.com
- PR Newswire. FDA Approves Zepbound® (tirzepatide) for Moderate-to-Severe OSA in Adults with Obesity. December 2024.
Related reading
- Changing Central Apnea Detection with Wesper
- OSA and GLP-1's
- What you need to know about GLP-1's for Obstructive Sleep Apnea
Article by Brett Figliozzi
Brett Figliozzi is the Marketing Manager at Wesper, where he leads brand strategy, content development, and digital communications. With a background in visual design and a focus on clinical storytelling, Brett oversees social strategy, conference branding, and blog development. He works with Wesper’s clinical team on campaigns that are engaging and clinically meaningful.
This article is for general information and is not medical advice. Talk to a healthcare provider about your sleep health.
