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Abstract: PO2072

Serum Magnesium, Blood Pressure, and Risk of Hypertension: Insights from the Chronic Renal Insufficiency Cohort (CRIC) Study

Session Information

Category: Hypertension and CVD

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

Authors

  • Correa, Simon, Brigham and Women's Hospital, Boston, Massachusetts, United States
  • Guerra Torres, Xavier E., Hospital Universitario Principe de Asturias, Alcala de Henares, Madrid, Spain
  • Waikar, Sushrut S., Boston Medical Center, Boston, Massachusetts, United States
  • McCausland, Finnian R., Brigham and Women's Hospital, Boston, Massachusetts, United States
Background

Magnesium (Mg) has been implicated in regulation of blood pressure (BP). Abnormalities in serum Mg (sMg) are common in CKD and ESRD due to decreased intestinal absorption, impaired renal handling and diuretics use. Studies assessing the association of sMg and BP are scarce, and the association of sMg with the risk of developing hypertension (HTN) is unknown.

Methods

We analyzed data from 3,866 participants from CRIC. Adjusted linear regression models assessed the association of sMg with SBP and DBP at baseline and adjusted smoothing splines were fit. Adjusted logistic regression models explored the association of baseline sMg with baseline HTN (CRIC-defined HTN: SBP ≥140 or DBP ≥90 or anti-HTN drug use; AHA-defined HTN: SBP ≥130 or DBP ≥80 or anti-HTN drug use) and sub optimally controlled blood pressure (SBP ≥120 or DBP ≥80). Adjusted cox-proportional hazard models stratified by clinical site explored the association of baseline sMg with incident HTN. All models were adjusted for demographics, CV comorbidities, eGFR, proteinuria, serum albumin, FGF-23, calcium, phosphate, total PTH, Na, K, urine Na, and urine K.

Results

Median sMg was 2.0 mEq/L (25th-75th percentile 1.9 to 2.1 mEq/L). Higher sMg at baseline was associated with lower SBP (-2.63 mmHg, 95% CI-5.01 to -0.25, per 1 mEq/L) and lower DBP (-2.75 mmHg, 95% CI -4.16 to -1.34, per 1 mEq/L) (Fig 1A, 1B). Higher sMg was associated with a lower risk of AHA-defined HTN at baseline (aOR 0.25, 95% CI 0.12-0.55, per 1 mEq/L), a lower risk of sub optimally controlled BP (aOR 0.22, 95% CI 0.10-0.53, per 1 mEq/L) but not with a higher risk of CRIC-defined HTN (aOR 0.77, 95% CI 0.50-1.20, per 1 mEq/L). In time-to-event analyses, higher baseline sMg was associated with a numerically lower risk of incident CRIC-defined HTN (aHR 0.68, 95% CI 0.40-1.13, per 1 mEq/L).

Conclusion

Higher sMg is associated with lower SBP, lower DBP and a nominally lower risk of incident HTN. Monitoring and optimal control of sMg should be considered in patients with CKD for improved BP control.