Among 178 heart failure patients not receiving airway pressure therapy — followed for a median 3.7 years after acute HF hospitalization — sleep apnea-specific hypoxic burden (SASHB) independently predicted the composite endpoint of cardiovascular death or HF rehospitalization, improving discrimination beyond established clinical risk factors (bootstrap ΔC-index 0.020; ΔBrier score −0.007). The standard apnea-hypopnea index (AHI) did not add statistically consistent prognostic value. In the full 230-patient cohort, both SASHB and AHI interacted with PAP therapy response, suggesting SASHB could guide treatment selection.
This finding matters because roughly 50–75% of heart failure patients have significant sleep-disordered breathing, yet trials like SERVE-HF and ISAACC have failed to show benefit from treating sleep apnea in HF, partly because AHI is a blunt instrument — it counts events without capturing oxygen debt. SASHB integrates desaturation depth and duration, arguably a more physiologically relevant insult to the failing heart. If SASHB can identify a hypoxia-burdened subgroup that genuinely benefits from PAP therapy, it could reframe negative trial results as population-misselection problems rather than treatment failures. Limitations are substantial: this is a single-center, post hoc observational analysis of only 230 patients, making causal inference impossible. Residual confounding is plausible, and follow-up loss could bias survival estimates. Critically, this is a preprint not yet peer-reviewed, so results and interpretations may change. Confirmatory prospective trials stratifying by SASHB are needed before clinical adoption.