 Atul Malhotra, MD

Weight Loss May Be Key to Resolving OHS, Says Atul Malhotra, MD 

, the 39th annual meeting of the Associated Professional Sleep Societies in Seattle, Atul Malhotra, PhD, a sleep medicine specialist at UC San Diego Health, presented “Obesity Hypoventilation Syndrome - Updates in Diagnosis, PAP, and Weight Management” on June 10th in Seattle. HCPLive sat down with Malhotra at the meeting to discuss updates in weight management for 

In the first half of the interview, Malhotra shared OHS updates regarding diagnosis and positive airway pressure (PAP), which can be viewed

. He discussed how, despite OHS being a common issue, arterial blood gases are not checked as often as they used to be.

However, examining serum bicarbonate is helpful for identifying OHS, a disorder that often worsens the prognosis of obstructive sleep apnea (OSA). OHS and OSA tend to occur at the same time with a raised bicarbonate level.

Many patients with OHS do not find relief with PAP. Even though Malhotra offered suggestions to improve PAP adherence—patient education, intensive support, maintaining nasal pain—he said weight management is the most helpful.

“Data suggest you need to lose about 25 or 30% [of] your body weight to resolve obesity hypoventilation syndrome,” Malhotra said.

Malhotra conducted a big clinical trial recently that showed appetite therapy was helpful in improving OSA and cardiovascular symptoms, such as systolic blood pressure, reactive protein sleep apnea, and hypoxic burden. In that study, weight loss of 18 to 20% was substantial.

“So, if I started 200 pounds, 20% weight loss would be 40 pounds, or bring me 260 pounds, quite a game changer for those patients,” Malhotra said. “But given the need [of] 25% - 30% weight loss to resolve obesity hypoventilation syndrome... current data suggests that your tirzepatide may not be enough to get you to resolution of that subset of patients.”

Malhotra highlighted another drug in the pipeline—retatrutide (Triple G), a GLP-1 with a glucagon agonist. He said that retatrutide looks promising in preliminary studies, providing up to 25% of weight loss.

“That might be what we need to see [for] resolution of obesity hypervalent syndrome, but bottom line is, we need more data,” he said.

Relevant disclosures for Malhotra include Eli Lilly and Company, LivaNova, Itamar, ZOLL Respicardia, Impulse Dynamics, Jazz Pharmaceuticals, and Eisai Inc.

Nowalk N, Malhotra A, Mokhlesi B, et al. Obesity Hypoventilation Syndrome - Updates in Diagnosis, PAP, and Weight Management. Presented at SLEEP 2025, the 39th annual meeting of the Associated Professional Sleep Societies, on Tuesday, June 10 in Seattle.

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At SLEEP 2025, Malhotra emphasized the need for weight loss to resolve obesity hypoventilation syndrome and highlighted limitations of current therapies.


Updates in Obesity Hypoventilation Syndrome Diagnosis, with Atul Malhotra, MD

Atul Malhotra, MD, a sleep medicine specialist at UC San Diego Health, presented “Obesity Hypoventilation Syndrome - Updates in Diagnosis, PAP, and Weight Management” at 

SLEEP 2025, the 39th annual meeting of the Associated Professional Sleep Societies

HCPLive sat down with Malhotra at the meeting to discuss these new updates and what they mean for 

 care. He talked about the most important updates in the diagnostic criteria or clinical approach to identify OHS in 2025 and what’s new in the management of OHS with positive airway pressure (PAP) therapy.

“We don't check as many arterial blood gases as we used to, and I think there's increasing awareness that obesity hypoventilation syndrome is a common problem, particularly [in] the sleep clinic,” Malhotra said. “Body Mass Index is 40, about a 30% prevalence of obesity. [With] obesity hypoventilation syndrome, if your body mass index is 50, it's about a 50% prevalence of obesity. Looking at the serum bicarbonate can be quite helpful, and high clinical suspicion can be quite helpful as well.”

He explained that when the bicarbonate level is elevated, obstructive sleep apnea (OSA) and OHS often coexist. OHS worsens the prognosis of OSA, leading to poor outcomes.

“[Assessing] blood gas during the daytime can be quite helpful because it's elevated in patients with obesity hypoventilation syndrome and typically not elevated in obstructive sleep,” Malhotra said.

Capnometry via an app can also be helpful. In clinical settings, experts have used polysomnography to measure carbon dioxide levels transcutaneously, but now patients have begun at-home capnometry through apps.

When bicarbonate rises, Malhotra said hypercapnia could be a cause, but also other influences such as steroids and diuretics. Glucocorticoids or thiazide diuretics can elevate bicarbonates via metabolic alkalosis.

“it's really not diagnostic of hypercapnia if you have a high bicarbonate, but should raise your clinical suspicion,” Malhotra said. “Especially if a bicarbonate is normal, it's less likely to be hypoventilation.”

When it comes to PAP, many patients have high adherence to this treatment, but do not feel any better.

“See, the usual things that we do in terms of PAP troubleshooting…You need to lose about 25 or 30% of your body weight to resolve hypoventilation syndrome,” Malhotra said. “Let's resolve the hypercapnia.”

At SLEEP 2025, Malhotra shared updates on diagnosing and managing OHS, including the role of bicarbonate, PAP use, and weight loss.

Atul Malhotra, MD

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