Low Serum Phosphate Linked to Risk of Heart Attack

Cardiovascular disease is a leading cause of mortality and morbidity worldwide, and high serum phosphate is an established risk factor for coronary artery disease, particularly in patients with chronic kidney disease.

Phosphate is an important mineral in the body and helps to regulate blood biochemistry, which can impact on the working of the heart. It plays a crucial role in enabling red blood cells to deliver oxygen to the body's tissues, and can be found in protein rich foods such as meat, poultry and fish.

Scientists at the University of Surrey (Guildford, UK) used data from the Royal College of General Practitioners (RCGP) Research and Surveillance Centre, and examined phosphate levels of more than 100,000 patients, over five and nine-year intervals, and the impact on their cardiac health. Patients aged between 18 and 90 years were included in the study. Influential demographic and physiological variables were identified for each patient as close as possible to time zero and before any cardiac event.

The physiological variables included systolic blood pressure, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, renal function (eGFR), diabetes status and blood markers HbA1c, corrected calcium, sodium, potassium, and albumin. In all cases, single measurements were used except for corrected calcium, which was recorded in a similar manner to serum phosphate with extraction of values recorded on the same dates as serum phosphate.

The investigators found that those with low levels (less than 0.75 mmol/L) of the mineral in their blood were at a similar risk of developing coronary problems as those with elevated levels (above 1.5 mmol/L). Instances of both conditions were high amongst those with low and excessive levels of phosphate in the blood; however cardiac events in those with mid-range (1-1.25 mmol/L) levels were significantly less. The present demonstrated that low, high-normal, and high serum phosphate were associated with primary cardiac disease events in a U-shaped relationship within a general UK population.

Andrew McGovern, MD, a co-author of the study, said, “Our findings shed new light on the role of phosphate in the body and its relationship to cardiovascular health. In light of our findings we would suggest that clinicians consider people with low phosphate levels to be at higher cardiovascular risk and assess ways in which this can be reduced for each patient.” The study was published on November 8, 2017, in the journal Public Library of Science ONE.

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