Nocturnal hypoxemic burden is associated with incident major adverse cardiovascular events in patients with type 2 diabetes.

Aims: Type 2 diabetes (T2D) prevalence is globally increasing and associated with cardiovascular disease. Whether oximetry-derived nocturnal hypoxemic burden (NHB) parameters are associated with incident major adverse cardiovascular events (MACE) in a population with T2D is not known.

Methods: Overnight oximetry data from patients enrolled in the DIACORE (DIAbetes COhoRtE) sleep-disordered breathing sub-study, a prospective German cohort study of patients with T2D, was analyzed. NHB as cumulative time spent below 90% oxygen saturation (T90) as well as its composition of T90 attributed to acute desaturations (T90desaturation) and non-specific drifts in oxygen saturation (T90non-specific) was assessed. MACE was defined as a composite outcome of myocardial infarction, stroke, and cardiovascular death. Cox hazard regression analyses adjusted for potential known risk factors for atherosclerosis were conducted.

Results: The analysis population consisted of 1255 participants (41% female, mean age 67 years, mean diabetes duration 9.6 years). After a median follow-up of 6.5 years, a MACE occurred in 149 (12%) patients. T90, but not apnea-hypopnea index, was significantly associated with an increased risk of incident MACE by 48% independently of other known risk factors for atherosclerosis (Quartile 4 vs. Q1-3 adjusted HR 1.48, 95% CI [1.04; 2.12], p=0.032). In particular, T90non-specific contributed to the elevated risk for incident MACE (Q4 vs. Q1-3 adjusted HR 1.62, 95% CI [1.14-2.30], p=0.007).

Conclusion: In the present study, NHB was associated with MACE in patients with T2D and can be easily measured using oximetry. Further investigations are warranted to establish T90 reduction as a clinically meaningful treatment target.