Which nocturnal hypoxemia parameters are associated with ambulatory blood pressure monitoring in adults with obstructive sleep apnea? A systematic review.

Clinical Snapshot

Key Findings

• P Value: Not reported at the review level; individual study p-values not synthesised

• Effect Size: No pooled effect size calculated; narrative synthesis only. ODI3% demonstrated the most consistent positive association with elevated BP across included studies. Minimum SpO2, mean SpO2, and T90% yielded variable and inconsistent findings across studies.

• Primary Outcome: Association between nocturnal hypoxemia parameters and elevated blood pressure measured by ABPM in adults with OSA

• Nnt Or Sensitivity: Not applicable; no quantitative synthesis. Hypoxic burden (HB) was evaluated in one study only, suggesting a potential role in BP reduction following CPAP therapy, but no effect size or NNT can be derived from the available evidence.

• Confidence Interval: Not reported; no meta-analysis performed

Clinical Application

ODI measurement is routinely available from standard polysomnography and home sleep testing devices, making it a feasible clinical marker without additional cost. ABPM is widely available in primary care and specialist settings. Hypoxic burden calculation requires specialised software and is not yet routinely available in clinical practice, limiting its immediate applicability. In Australia, OSA is highly prevalent, with an estimated 5–10% of adults affected. ABPM is a Medicare Benefits Schedule (MBS) item (MBS item 11707) for the investigation of hypertension, and its use in OSA patients with suspected hypertension is consistent with RACGP hypertension guidelines. CPAP therapy is the first-line treatment for moderate-to-severe OSA and is available through private health insurance and public hospital sleep services; however, it is not PBS-subsidised as a device. The TGA has approved multiple CPAP devices and pulse oximetry systems used to derive ODI. The finding that ODI3% is the most consistent hypoxemia marker associated with elevated BP supports its use as a cardiovascular risk stratification tool in Australian sleep clinics, though clinicians should note the absence of quantified effect sizes. RACGP guidelines recommend screening for hypertension in OSA patients, and this review supports the clinical rationale for ABPM in this population. The preliminary evidence for hypoxic burden is not yet actionable in Australian clinical practice. Adults with confirmed OSA (by polysomnography or home sleep testing) who are being evaluated for cardiovascular risk, particularly systemic hypertension. Most applicable to patients with moderate-to-severe OSA in whom nocturnal hypoxemia is a prominent feature. Patients with resistant hypertension undergoing ABPM workup represent a high-priority subgroup.

Abstract

OBJECTIVE: Systemic arterial hypertension affects up to 50% of patients with obstructive sleep apnea (OSA) and represents one of the main modifiable cardiovascular risk factors. Hypoxemia is a recognized marker of OSA severity; however, it remains unclear which specific desaturation parameters during sleep, such as oxygen desaturation index (ODI), mean and minimum oxygen saturation (SpO2), percentage of sleep time with peripheral oxygen saturation < 90% (T90%) or hypoxic burden (HB) are most consistently associated with elevated blood pressure (BP). This systematic review aims to evaluate, in patients with OSA, the impact between nocturnal desaturation parameters and elevated BP as measured by ambulatory blood pressure monitoring (ABPM). METHODS: A literature search was performed in PubMed, Web of Science, Scopus and Embase databases, covering all records available up to June 2025. RESULTS: A total of 5,587 records were identified through database searches, and 24 studies met the inclusion criteria. The studies revealed heterogeneous results, with some showing significant associations between hypoxemia indices and hypertension, while others did not. Evidence suggests that ODI3% is commonly related to increased BP, whereas minimum SpO2, mean SpO2 and T90% yielded variable findings. HB was evaluated in only one study, suggesting a potential role in BP reduction after CPAP; however, the available evidence remains preliminary. CONCLUSION: ODI3% showed the most consistent association with increased BP across studies, whereas other hypoxemia indices yielded more variable results. Evidence regarding HB remains preliminary and warrants further investigation. These findings suggest that although ODI currently appears to be the most reliable marker, evidence from a single study indicates that composite indices such as HB may represent more informative predictors of BP outcomes and deserve further investigation in future studies.

References

1. 1.Rosa, C. F. A., de Paula Soares, C. F., & Cahali, M. B. (2026). Which nocturnal hypoxemia parameters are associated with ambulatory blood pressure monitoring in adults with obstructive sleep apnea? A systematic review. Sleep & Breathing. https://doi.org/10.1016/j.arbres.2022.08.005