Single-Night Diagnosis of Sleep Apnea Contributes to Inconsistent Cardiovascular Outcome Findings

Background: Single-night disease misclassification of OSA due to night-to-night variability may contribute to inconsistent findings in OSA trials. 

Research Question: Does multinight quantification of OSA severity provide more precise estimates of associations with incident hypertension? 

Study Design and Methods: A total of 3,831 participants without hypertension at baseline were included in simulation analyses. Included participants had ≥ 28 days of nightly apnea-hypopnea index (AHI) recordings via an under-mattress sensor and ≥ three separate BP measurements over a 3-month baseline period followed by ≥ three separate BP measurements 6 to 9 months postbaseline. Incident hypertension was defined as a mean systolic BP ≥ 140 mm Hg or a mean diastolic BP ≥ 90 mm Hg. Simulated trials (1,000) were performed, using bootstrap methods to investigate the effect of variable numbers of nights (x = 1-56 per participant) to quantify AHI and the ability to detect associations between OSA and incident hypertension via logistic regression adjusted for age, sex, and BMI. 

Results: Participants were middle-aged (mean ± SD, 52 ± 12 y), mostly males (91%), and overweight (BMI, 28 ± 5 kg/m²). Single-night quantification of OSA failed to detect an association with hypertension risk in 42% of simulated trials (α = .05). Conversely, 100% of trials detected an association when AHI was quantified over ≥ 28 nights. Point estimates of hypertension risk were also 50% higher and uncertainty was five times lower during multinight vs single-night simulation trials. 

Interpretation: Multinight monitoring of OSA allows for better estimates of hypertension risk and potentially other adverse health outcomes associated with OSA. These findings have important implications for clinical care and OSA trial design.