Kidney Week

Abstract: TH-PO449

Renal Impairment Modifies the Association Between Sodium Intake and Risk of Stroke – An Analysis of INTERSTROKE

Session Information

• Hypertension and CVD: Epidemiology, Risk Factors, Prevention
  October 25, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Hypertension and CVD

• 1401 Hypertension and CVD: Epidemiology, Risk Factors, and Prevention

Authors

• Judge, Conor S., Health Research Board Clinical Research Facility, Galway, Ireland, Ireland

Conor S. Judge,

• Smyth, Andrew, NUI Galway, Galway, Ireland

Andrew Smyth,

• O'donnell, Martin, NUI Galway, Galway, Ireland

Martin O'donnell,

Group or Team Name

• Conor Stephen Judge

Background

Stroke is the second most common cause of death and the third most common cause of disability worldwide (1). Excess sodium intake, and renal impairment, are associated with an increased risk of stroke. We performed an analysis of the INTERSTROKE case-control study to investigate the relationship between estimated urinary sodium excretion (used as a surrogate for intake) and stroke.

Methods

INTERSTROKE was a standardized international case-control study that recruited 26,919 participants in 32 countries (2). We included participants with urine samples collected and measurement of spot urine sodium, potassium, and creatinine. 24-hour urinary sodium excretion was estimated using the Kawasaki, Intersalt, and Tanaka equations (7–9). Multivariable unconditional logistic regression was performed to compare the risk of stroke across four quartiles (<3.2 g/day, 3.2–4.4 g/day, 4.4–5.8 g/day, >5.8 g/day) of estimated 24-hour urinary sodium excretion using 3.2–4.4g/day as the reference quartile, as this was the category with lowest risk.

Results

Of the 26,945 participants, 13,483 were cases and 13,462 were controls. 23,258 participants had urine collected and processed. Mean eGFR (CKD-EPI) was 79.83 (23.49) ml/min/1.73m². Mean 24-hour estimated sodium excretion was 3.56 (1.95) g/day for cases and 3.43 (1.56) g/day for controls (p<0.001). After adjustment for age, sex, hypertension, diabetes, ethnicity, and region, <3.2 g/day (OR 1.38 [1.28-1.48]) and >5.8 g/day (OR 1.67 [1.55-1.79]) of sodium excretion were both associated with increased odds of stroke (ischaemic stroke and intracerebral hemorrhage). 4.4 – 5.8 g/day was not significant (OR 1.05 [0.97-1.13]). The pattern of association across quartiles was consistent with 24-hour sodium excretion estimated with Intersalt and Tanaka equations. The magnitude of association increases across each CKD stage (Table 1).

Conclusion

Our data report that renal function amplifies the association of sodium intake with stroke, and suggest that moderate stroke intake is associated with lowest stroke risk in all stages of renal impairment.