Hyperuricemia may be a contributing factor to secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease (CKD), possibly independent of renal function, investigators suggest.
Among 922 patients with stages 3 or higher CKD not on dialysis, SHPT and hyperuricemia occurred in 70% and 62.4%, respectively. The group with vs without SHPT had significantly higher mean levels of serum uric acid (7.2 vs 6.6 mg/dL) and a significantly higher prevalance of hyperuricemia (66% vs 33%), Rosilene M. Elias, MD, and colleagues from Hospital das Clinicas HCFMUSP in Sao Paulo, Brazil, reported in International Urology and Nephrology. In multivariable analyses, hyperuricemia remained independently associated with SHPT even after adjustments for estimated glomerular filtration rate, serum calcium, serum phosphate, low vitamin D, and relevant medications, including allopurinol, furosemide, calcitriol, and cholecalciferol.
Other research suggests hyperuricemia suppresses 1-α-hydroxylase leading to lower 1,25-hydroxyvitamin D2 and higher PTH levels. Deficiency of 25-hydroxyvitamin D [25(OH)D] was observed in 64.7% of the study population. Mean levels of 25(OH)D were significantly lower in patients with than without SHPT (26.6 vs 29.9 ng/mL).
The study lacked data on calcitriol and fibroblast growth factor 23 levels, which is a study limitation.
“Taken together, our findings suggested that the relationship between uric acid, hypovitaminosis D, and SHPT (or even increase in PTH levels) might not be explained only because of a decreased renal function,” Dr Elias’ team stated.
Costa TEM, Lauar JC, Innecchi MLR, Coelho VA, Moysés RMA, Elias RM. Hyperuricemia is associated with secondary hyperparathyroidism in patients with chronic kidney disease. Int Urol Nephrol. Published online January 31, 2022. doi:10.1007/s11255-022-03116-5