Sustained hypoxaemia predicts unprovoked VTE in OSA

In patients with obstructive sleep apnoea (OSA), the number of minutes during a night of sleep where a patient's oxygen saturation is 90% or lower (T90) was associated with the incidence of unprovoked venous thromboembolism (VTE). In contrast, the apnoea hypopnoea index (AHI), reflecting intermittent hypoxaemia in patients with OSA, was not a good predictor for VTE.

Several pathophysiological studies suggest that OSA might be a risk factor for VTE [1]. However, a recent cohort study showed that the AHI may not be as good as a predictor for VTE as for sustained hypoxaemia [2]. Prof. Wojciech Trzepizur (University of Angers, France) and his research team evaluated the relation between several measures of nocturnal hypoxaemia and unprovoked VTE in patients with OSA, to confirm the results of this recent study [3]. Between 2007 and 2018, the disease profile of 7,355 patients with suspected OSA was composed via OSA severity markers, AHI, T90, the oxygen desaturation index (ODI), and the hypoxic burden (total area under the respiratory event-related desaturation curve).

Participants who experienced an unprovoked VTE (n=142) were generally older, had a higher BMI, and were more likely to have comorbidities. The unadjusted analysis showed a significant effect of T90 on the incidence of VTE (log T90; HR 1.10; P<0.0001). Likewise, a higher hypoxic burden was related to an increased occurrence of VTE. AHI and ODI did not demonstrate a link with the incidence of VTE. After adjustment for demographic factors and comorbidities, T90 was still associated with an increased risk of VTE events (log T90; HR 1.06; P=0.0216). Moreover, in participants who had an oxygen saturation below 90% for more than 6% of their total sleep time, the risk of unprovoked VTE was doubled (HR 1.98; P=0.0359). Hypoxic burden was no longer a significant predictor of VTE after controlling for confounding factors. Finally, the authors did not find an association between CPAP adherence and the risk of VTE.

“T90 was the only independent predictor of VTE in this study,” stressed Prof. Trzepizur. “These findings are consistent with the results that were reported by Genuardi et al. [2], confirming that T90 plays an important role in the occurrence of VTE events in patients with OSA.”

1. Alonso-Fernandez A, et al. Sleep Med Rev. 2020;50:101223.
2. Genuardi MV, et al. Chest. 2022;161(4):1073–1082.
3. Trzepizur W, et al. Sleep apnea and incident unprovoked venous thromboembolism: Data from the French Pays de la Loire Sleep Cohort. Obstructive sleep apnea consequences and management, OA2288, ERS International Congress 2022, Barcelona, Spain, 4–6 September.

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Posted on 30 October, 202220 February, 2024