CHEST Guidelines-Response_chest

Response_chest_13 (4)

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The document discusses the surprising finding that in patients with obesity hypoventilation syndrome (OHS), those with severe obstructive sleep apnea (OSA) have a lower prevalence of cardiovascular morbidity (CVM). This inverse relationship is suggested to be due to ischemic preconditioning, a potential protective mechanism. The authors used a logistic regression to compare CVM across three tertiles based on the oxygen desaturation index but noted significant phenotypic differences in the most severe group, such as being younger, more active, and including fewer hypertensive or diabetic patients.<br /><br />To further explore this counterintuitive result, the authors propose using biomarkers like high-sensitivity cardiac troponin T (hs-cTnT), which has been linked to OSA severity and the risk of heart failure. Despite first-generation troponin assays initially showing no relationship between circulating troponins and OSA severity, the improved sensitivity of newer assays indicates that hs-cTnT might be relevant in future studies to verify these findings.<br /><br />Responses from other researchers call attention to the need for cautious interpretation, considering the data as hypothesis-generating. They stress that multivariate regression models cannot account for all confounders and that additional research using biomarkers like hs-cTnT could provide insights into whether OSA severity is indeed associated with reduced CVM risk in OHS patients. They also highlight the potential biases present, such as selection biases that may skew the perceived relationship between OSA severity and CVM.<br /><br />Overall, this discussion opens up a novel debate about the potential cardioprotective effects of severe OSA in the context of OHS, suggesting the need for further research to confirm these findings and understand the underlying molecular mechanisms.

Keywords

obesity hypoventilation syndrome

obstructive sleep apnea

cardiovascular morbidity

ischemic preconditioning

oxygen desaturation index

high-sensitivity cardiac troponin T

multivariate regression

biomarkers

cardioprotective effects

molecular mechanisms