0495 Sex-Specific Delta Heart Rate Variation Across Age and BMI in Obstructive Sleep Apnea Among Hispanic/Latino Individuals

Abstract Introduction Introduction: Delta Heart Rate (ΔHR) reflects autonomic changes during respiratory events and may provide complementary physiological information beyond traditional obstructive sleep apnea (OSA) metrics. We examined sex-specific patterns of ΔHR and its associations with event frequency, age, and Body Mass Index (BMI) -defined strata. Methods Methods: We analyzed 913 adults (463 women). ΔHR was defined as the difference between the maximum pulse rate within a subject-specific search window spanning from a pre-event minimum to a post-event minimum and the minimum pulse rate during apneas or hypopneas, emphasizing ensemble-averaged, time-averaged changes over 10–30 seconds. OSA severity was assessed using the apnea–hypopnea index (AHI), oxygen desaturation index (ODI), and percentage of sleep time with SpO₂ < 90% (CT90). Group comparisons used t-tests and chi-square tests. Associations between age, BMI categories, and severity metrics were examined through sex-stratified linear models. Results Results: Mean age was 55.3±13.1 years and BMI 35.6±8.4 kg/m2. Men showed higher AHI (40.5±28.4 vs. 29.0±26.8 events/h), ODI (40.4±27.7 vs. 30.7±27.3 events/h), CT90 (35.4±30.8% vs. 31.9±32.4%), and ΔHR (5.54±2.93 vs. 4.18±1.97 bpm) compared with women (all p< 0.001). ΔHR varied across age and BMI strata in both sexes. In women, ΔHR showed a graded decline with age (β for 45–59 = –0.34; β for ≥60 = –1.10; p< 0.001 for trend), while AHI, CT90 and ODI increased across age and BMI categories. In men, ΔHR also decreased with age (β for 45–59 = –0.80; β for ≥60 = –1.50; p< 0.001 for trend) and increased among those with BMI ≥40 (β = +1.79; p=0.001). Conclusion Conclusion: ΔHR displays distinct sex-specific patterns, characterized by an age-related decline in both sexes and a BMI-related increase restricted to men. ΔHR provides complementary physiological information that enhances the characterization of autonomic responses to respiratory events. These findings support incorporating ΔHR alongside traditional metrics in population-level assessments. Support (if any) GL was supported by Fondecyt grant (Chile) number 11240972