Azarbarzin, Ali

Objective: To determine whether sleep apnea–specific hypoxic burden (SASHB) is associated with self-reported hypertension beyond conventional obstructive sleep apnea metrics in rail workers. Methods: Cross-sectional study of 84 Argentine rail workers undergoing home sleep apnea testing. Associations between SASHB and hypertension were evaluated using adjusted logistic regression. Drowsy driving was examined as an unadjusted exploratory secondary outcome. Results: Higher SASHB was independently associated with hypertension in the fully adjusted model (OR per SD 2.42; 95% CI 1.24–5.29; p=0.015). Higher SASHB was also associated with more severe self-reported drowsy driving in unadjusted exploratory ordinal analyses (OR per SD 1.78; 95% CI 1.09–3.28; p=0.035). Conclusions: SASHB may provide complementary information beyond conventional OSA metrics for cardiovascular risk assessment in occupational populations.

AbstractNocturnal hypoxemia is a prevalent feature of various respiratory diseases, significantly impacting patient outcomes and therapeutic strategies. Oximetry, a noninvasive and widely accessible tool, enables the measurement of nocturnal hypoxemia through oxyhemoglobin saturation (SpO2)-derived metrics such as the oxygen desaturation index, percentage of sleep time with SpO2 below 90%, mean SpO2, and measures of the area under the desaturation curve (e.g., sleep apnea-specific hypoxic burden). While these metrics are well established in obstructive sleep apnea (OSA), their application in other respiratory conditions, including chronic obstructive pulmonary disease, pulmonary hypertension, obesity hypoventilation syndrome, heart failure, neuromuscular disorders, pregnancy, and high-altitude residents, remains an area of active investigation. This review explores the pathophysiology of hypoxemia in these conditions and evaluates the role of SpO2-derived metrics in risk stratification beyond OSA. We also discuss the challenges of interpreting SpO2 data, particularly the difficulty differentiating disease-related hypoxemia from comorbid OSA. Additionally, we examine the limitations of oximetry, including sensor inaccuracies, motion artifacts, and skin pigmentation. Finally, we emphasize the need for further research to standardize these metrics across diverse conditions and advocate for their integration into clinical practice to enhance patient management and outcomes.

Abstract Background: Obstructive sleep apnea (OSA) is associated with obesity and cardiovascular risk. Results from the SURMOUNT-OSA studies demonstrated significant reduction of a number of cardiometabolic risk measures in participants with OSA and obesity following treatment with tirzepatide. Objectives: Systematically analyze all tirzepatide treatment related changes of cardiometabolic risk measures in SURMOUNT-OSA studies and investigate to what extent these changes were mediated by reductions in weight and/or OSA-related measures. Methods: The SURMOUNT-OSA master protocol comprised two 52-week, randomized, double-blind, placebo-controlled Phase 3 studies. Study 1 (N=234) and 2 (N=235) included participants with moderate-to-severe OSA and obesity, who at screening reported not using, or using positive airway pressure (PAP) therapy, respectively. The design and rationale of the studies have been published previously (1). The current analysis investigated the association of treatment with tirzepatide or placebo with SURMOUNT-OSA pre-specified cardiometabolic risk measures including blood pressure, and levels of high-sensitivity C-reactive protein (hsCRP), HDL-C, non-HDL-C, triglycerides, fasting insulin. Further analyses included change in HOMA-IR with tirzepatide compared to placebo, and mediation analysis to determine the proportion of observed changes attributable to reductions in body weight, apnea-hypopnea index (AHI) and sleep apnea-specific hypoxic burden (SASHB). Results: In Study 1, participants experienced greater difference in change from baseline with tirzepatide compared to placebo in SBP (-7.9 mmHg; 95% CI -11.0 to -4.9; p<0.001), and DBP (-3.2 mmHg; 95% CI -5.4 to -1.0; p=0.005) at 48 weeks, and hsCRP (-28.9±8.2%; p=0.003), HDL-C (7.2±2.1%; p<0.001), non-HDL-C (-13.0±3.1%; p<0.001), triglycerides (-32.2±3.7%; p<0.001), fasting insulin (-41.4±5.0%; p<0.001), and HOMA-IR (-48.0±4.9%; p<0.001) at 52 weeks. In Study 2, participants experienced greater differences in change from baseline following tirzepatide compared to placebo in SBP (-4.3 mmHg; 95% CI -7.3 to -1.2; p=0.007) at 48 weeks, and hsCRP (-45.1±8.0%; p<0.001), HDL-C (10.0±2.8%; p<0.001), non-HDL-C (-14.3±2.5%; p<0.001), triglycerides (-31.5±3.7%; p<0.001), fasting insulin (-45.4±5.4%; p<0.001), and HOMA-IR (-54.8±5.0%; p<0.001) at 52 weeks. Statistically significant independent mediation effect of changes in OSA metrics was observed on hsCRP, HOMA-IR and triglycerides. In addition, the combination of changes in weight and OSA metrics, but not weight or OSA improvements alone, had a significant mediation effect on non-HDL-C. There was no significant mediation effect of weight or OSA metrics observed on DBP. Conclusions: In the SURMOUNT-OSA program trials, tirzepatide appeared to have significant cardiometabolic benefits for patients with moderate-to-severe OSA and obesity. Based on the mediation analysis, treating both sleep-disordered breathing and obesity is likely required to optimize cardiometabolic benefits for patients with OSA and obesity.