Evaluation of urinary na levels as a risk factor in patients with coronary artery disease

INTRODUCTION: Restriction of salt intake is advised in the general population to reduce cardiovascular risk. Daily higher salt intake may contribute to high coronary artery disease (CAD) prevalence in the Turkish population, although there is limited data regarding salt intake and urinary sodium (Na) extraction in patients with CAD. In this study, we aimed to assess the relationship between urine Na, potassium (K), protein and creatine levels in patients with CAD. METHODS: One hundred participants, aged 30-65, who underwent coronary angiography under elective conditions were enrolled in this study between May 2019 and August 2019. Patients who had known CAD before, acute coronary syndrome, hypertension, congestive heart failure, diabetes mellitus (DM), structural heart disease, malignancy, renal failure, and severe comorbid states were excluded from the study. Coronary angiograpy revealed CAD in 61 patients and normal coronary arteries in 39 patients who were classified as the control group. Morning urine samples were collected for analysis. The 24-hour urine sodium was calculated using the KAWASAKI method. RESULTS: Spot urinary protein extraction and spot urinary micro-protein/creatinine ratio were significantly higher in the CAD group than in the control group (p=0.035, p=0.031, respectively). Also, serum creatinine (Cr) was found to be higher while glomerular filtration rate (GFR) and Na levels were found to be lower in the CAD group than in the control group (p=0.014, p = 0.012, p=0.016 respectively). The logistic regression model was statistically significant, chi(2)(25)=41.45. p =0.021 and GFR, Na levels, spot urinary micro-protein/ creatinine, and HDL levels were assessed as predictive factors for CAD. CONCLUSION: Urinary Na and K extraction is not affected by the presence of CAD. Also, spot urinary Na/ K ratio and 24-hour sodium extraction were similar between patients with and without CAD. However, decreased GFR and increased urinary micro-protein/creatinine ratio could be risk factors for CAD. Furter studies with large samples are needed to assess this relationship.