Prevalência das alterações do metabolismo mineral e ósseo em pacientes com doença renal crônica em terapia renal substitutiva – um estudo em centros de nefrologia da AMICEN

Abstract

Introduction: The dialytic chronic kidney disease (CKD) is a growing public health problem worldwide, including Brazil, according to Brazilian Chronic Dialysis Survey 2013 it was estimated 100,397 patients on renal replacement therapy (RRT) with the prevalence 499 patients per million. In CKD, there are a complications and comorbidities (anemia, hyperphosphatemia, chronic metabolic acidosis, among others). One of the comorbidities associated to CKD is the mineral and bone disorder (CKD-MBD), a syndrome, which encompasses clinical, biochemical (calcium, phosphate, parathyroid hormone, and vitamin D related) and bone abnormalities (bone remodeling, mineralization, and bone volume related), in addition to the comorbidities associated with extra-skeletal calcification and cardiovascular disturbances. As far, we know there are not national studies assessing changes mineral and bone metabolism, the use of phosphate binders (calcium carbonate, calcium acetate and sevelamer), the use of vitamin D and analogues (calcitriol and alfacalcidol), use vitamin D selective receptor activators (paricalcitol) and the use of calcimimetic (cinacalcet) in individuals with CKD in hemodialysis and peritoneal dialysis. The primary aim of this study was to evaluate the prevalence, biochemical profile, and drugs associated with CKD-MBD in these patients. The secondary aim was to compare the KDIGO targets with our results. Patients and methods: Cross-sectional study between July/November 2013 from 11 nephrology centers of AMICEN, with 1134 patients over 18 years, on dialysis for >3 months, with at least a PTHi dosage in 2013. The population was divided in groups, based on intact parathyroid hormone (PTHi) levels (based KDOQI, KDIGO classification and Douthat et al), and socio-demographic, clinical and laboratorial data was compared between the groups. Linear regression analysis was performed to determine the variables that influence the PTHi level. Results: The mean age was 57.3±14.4 years, 55.6% males, and 48% White. The main etiology was hypertensive nephropathy (40.9%). There were 1071 patients on hemodialysis and 63 on peritoneal dialysis. The prevalence of PTHi<150 pg/mL was 23.4% and PTHi>600pg/mL was 27.1%. Comparison of the PTHi groups showed that PTHi levels decrease with increasing age (60.4±14.9 vs 51.4±13.2, p < 0.0001). Diabetic renal disease patients presented a higher prevalence of PTHi<150 pg/mL (27.6%) and a lower prevalence of PTH > 1000 pg/mL (2.4%). Calcium carbonate was used by 50.5% of the patients, 14.7% used non-calcium-based binders. Over 40% of the patients used vitamin D and 3.5% used calcimimetics. Hyperphosphatemia was observed in 35.8%. Linear regression analysis showed a significant negative association between the PTHi, age and diabetes mellitus and a significant positive association between the therapy duration and the PTHi levels. Conclusion: The prevalence of patients outside the PTHi target, based on KDIGO, was 50.5%. High prevalence of hyperphosphatemia and a low use of vitamin D and selective activators as well as calcimimetics. These data draw attention to the need for a stronger compliance with public policies and guidelines regarding the supply of drugs associated with CKD-MBD.