Elevated C-Reactive Protein in Patients With Obstructive Sleep Apnea

TLDR

Obstructive sleep apnea is increasingly linked to cardiovascular and cerebrovascular disease, possibly via inflammatory pathways. The study aimed to determine whether OSA patients exhibit higher plasma C‑reactive protein levels. Twenty‑two newly diagnosed, untreated OSA patients were compared to 20 age‑ and BMI‑matched controls, with CRP measured in both groups. OSA patients had significantly higher CRP, which correlated independently with disease severity, indicating that CRP elevation is proportional to OSA severity.

Abstract

Background — Obstructive sleep apnea (OSA) has been increasingly linked to cardiovascular and cerebrovascular disease. Inflammatory processes associated with OSA may contribute to cardiovascular morbidity in these patients. We tested the hypothesis that OSA patients have increased plasma C-reactive protein (CRP). Methods and Results — We studied 22 patients (18 males and 4 females) with newly diagnosed OSA, who were free of other diseases, had never been treated for OSA, and were taking no medications. We compared CRP measurements in these patients to measurements obtained in 20 control subjects (15 males and 5 females) who were matched for age and body mass index, and in whom occult OSA was excluded. Plasma CRP levels were significantly higher in patients with OSA than in controls (median [range] 0.33 [0.09 to 2.73] versus 0.09 [0.02 to 0.9] mg/dL, P <0.0003). In multivariate analysis, CRP levels were independently associated with OSA severity (F=6.8, P =0.032). Conclusions — OSA is associated with elevated levels of CRP, a marker of inflammation and of cardiovascular risk. The severity of OSA is proportional to the CRP level.