Uric acid and Sleep related hypoxemia in a Tunisian population with atrial fibrillation: What kind of association?

Introduction Intermittent hypoxia is the most prominent characteristic of sleep disordered breathing. This leads through several metabolic processes, to the release of ATP catabolic end product, uric acid. These findings make us wonder if the elevated levels of serum uric acid can be suggested to be a good index of tissue hypoxia. Purpose The aim of this study was to verify whether the nocturnal hypoxia was associated with an increased level of serum uric acid in a Tunisian population with atrial fibrillation (AF), which would be a biological marker of sleep disordered breathing in this population. Methods It was a descriptive study which included 100 patients followed for non-valvular AF. They were all referred for overnight polygraphy. Fasting blood samples were obtained to dose serum uric acid. Non inclusion criteria were patients followed for gout and/or being on allopurinol treatment, renal failure (clearance of creatinine  Results The average age was 66 ± 9 years. Hypertension was the most prevalent risk factor present in 72% of patients. The mean value of serum uric acid was 61.05 ± 19.4 mg/l. Hyperuricemia was found in 31 patients. The average value of mean desaturation and minimal desaturation were respectively 93 ± 2% and 83 ± 7%. There were no significant association between these 2 parameters and uric acid levels with p values respectively of 0.19 and 0.33. The desaturation index mean value was 18.8 ± 13.4. A significant correlation was found between the serum uric acid values and the desaturation index (P = 0.02). Total desaturation time under 90% was of 21 ± 44 minutes but wasn’t correlated with uric acid values (P = 0.39). Conclusion The relationship between desaturation index and serum uric acid found in our study conducted in a Tunisian population with AF, suggests that sleep apnea in these patients is severe enough to cause tissue hypoxia, which is marked by increased levels of serum uric acid.