High prevalence of secondary hyperparathyroidism in chronic kidney disease patients on dialysis in Argentina

Background: There are few data in Argentina on the prevalence and management of bone and mineral metabolism (BMM) in patients with chronic kidney disease (CKD). Objectives and methods: A survey was carried out in dialysis units in 2010 to measure the prevalence of and types of treatments for BMM disorders in Argentina. The data obtained was then compared to the published results from other large population studies. We recorded characteristics of dialysis centres and participating patients, the frequency of measurements and individual results for BMM biochemical markers, as well as the type of management used to control hyperphosphataemia and secondary hyperparathyroidism. Results: 1210 patients from 25 dialysis centres in Argentina participated in the study (representing 4.7% of the country's prevalent dialysis population in 2010). The mean patient age was 55.3 +/- 17.6 years, 60.8% were male, 3.3% were on peritoneal dialysis and 29.1% suffered diabetes. In all centres, phosphataemia and calcaemia were measured on a monthly basis, 60% of centres measured intact parathyroid hormone (iPTH) every 6 months, 36% every 3 to 4 months, and 4% annually. As recommended by K/DOQI, 51.6% of patients had adequate levels of calcium (8.4-9.5mg/dl), 51.6% had adequate phosphorus (3.5-5.5mg/dl) and 21.1% displayed acceptable iPTH levels (150-300pg/ml). 24% had iPTH <150pg/ml and 54.5% >300pg/ml. iPTH >600pg/ml was present in 28.3%, and 13.3% had values >1000pg/ml. These figures differed from those published by the DOPPS II study, in which 51.1% of patients had iPTH <150pg/ml, and only 26.7% had iPTH >300pg/ml. Calcium-based phosphate binders were used in 83.6% of the patients, 5.6% used sevelamer and 4.0% used aluminium-containing compounds. To achieve control of hyperparathyroidism, oral or intravenous calcitriol was predominantly used (50.5%) with a small percentage of patients receiving paricalcitol or doxercalciferol. Conclusions: The present study shows a high prevalence of secondary hyperparathyroidism, which differs from that published by other large population studies. There was a high proportion of patients with BMM markers outside the ranges suggested by K/DOQI. Mainly phosphate binders based on calcium and calcitriol continue to be used for the management of hyperphosphatemia and hyperparathyroidism respectively.