Phosphate-binders Increase Blood Pressure in CKD Patients

Serum phosphate concentrations rise as chronic kidney disease (CKD) progresses and, higher concentrations are associated with vascular calcification, cardiovascular events, and all-cause mortality. The relationship between serum phosphate and BP is less established, but emerging data suggest that higher levels may induce microvascular dysfunction and increase BP. Therefore, Dr Mitra S. Jamshidian, MD, MS and team conducted a study to evaluate the association between phosphate-lowering medications and BP in advanced CKD.

Researchers conducted a post hoc analysis of the COMBINE (CKD Optimal Management with Binders and Nicotinamide) trial, that involved 205 patients, who were randomly assigned to receive either lanthanum carbonate or nicotinamide, an inhibitor of active intestinal phosphate transport, or placebo.

Key findings of the study were:

• At baseline, eGFR was 32±7 ml/min/1.73 m2, serum phosphate was 3.7±0.6 mg/dl, and BP was 129±17/71±12 mmHg. Researchers noted that about 94% of the participants were on antihypertensive medications.

• After12 months of trial, they found that lanthanum carbonate users had a significant 5.52 mm Hg increase in systolic blood pressure compared with nonusers. However, the diastolic blood pressure remained similar between the groups.

• They reported that the effect on SBP was observed by the 3-month follow-up visit. They further added, " The mechanism by which LC is associated with increased SBP may be independent of its effects on phosphate absorption."

• Based on these findings, they suggested that LC may reduce the gastrointestinal absorption of antihypertensive medications.

• They also wrote that the FDA approval for LC warns that it may impair absorption of angiotensin-converting-enzyme inhibitors (ACEI) and recommends against their concurrent use of LC.

The authors concluded, " Given the widespread use of phosphate binders in CKD, the very high prevalence of hypertension, FDA warnings about co-administration of LC with ACEI, and the large magnitude of change in SBP we observed, future studies to confirm these findings and determine the mechanisms should be a high priority."

For further information:

https://www.ajkd.org/article/S0272-6386(21)00009-3/fulltext#%20