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Open Access Highly Accessed Research article

Antiproteinuric effect of add-on paricalcitol in CKD patients under maximal tolerated inhibition of renin-angiotensin system: a prospective observational study

Luca De Nicola14*, Giuseppe Conte1, Domenico Russo2, Antonio Gorini3 and Roberto Minutolo1

Author affiliations

1 Nephrology Departments at Second University, Napoli, Italia

2 University Federico II, Napoli, Italia

3 S. Giovanni Evangelista Hospital, Tivoli, Italy

4 Cattedra di Nefrologia - Dip. Gerontologia, Geriatria, Mal. Metabolismo, Seconda Università di Napoli, Facoltà di Medicina, Piazza Miraglia, 80131, Napoli, Italia

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Citation and License

BMC Nephrology 2012, 13:150  doi:10.1186/1471-2369-13-150

Published: 20 November 2012

Abstract

Background

Whether paricalcitol (PCT) reduces proteinuria in the presence of intensified inhibition of Renin-Angiotensin-System (RAS) is poorly studied. We evaluated the antiproteinuric effect of PCT in non-dialysis chronic kidney disease (CKD) patients with proteinuria greater than 0.5 g/24 h persisting despite anti-RAS therapy titrated to minimize proteinuria in the absence of adverse effects.

Methods

Forty-eight CKD patients were studied in the first six months of add-on oral PCT (1 mcg/day) and three months after drug withdrawal.

Results

Males were 87.5%, age 63 ± 14 yrs, systolic/diastolic blood pressure (BP) 143 ± 22/78 ± 11 mmHg, eGFR 29.7 ± 14.5 mL/min/1.73 m2, diabetes 40%, and cardiovascular disease 38%. At referral in the center (28 months prior to study baseline), proteinuria was 2.44 (95% CI 1.80-3.04) g/24 h with 6 patients not receiving any anti-RAS and 42 treated with a single agent, at low dosage in most cases. At study baseline, twenty patients were under 2–3 anti-RAS drugs while twenty-eight received 1 agent at full dose and proteinuria resulted to be reduced versus referral to 1.23 g/24 h (95%CI 1.00-1.51). Six months of add-on PCT significantly decreased proteinuria to 0.61 g/24 h (95%CI 0.40-0.93), with levels less than 0.5 g/24 h achieved in 37.5% patients, in the absence of changes of BP and GFR. Proteinuria recovered to basal value after drug withdrawal. The extent of antiproteinuric response to PCT was positively associated with diabetes, eGFR and daily Na excretion (R2 = 0.459, P < 0.0001). PTH decreased from 201 (IQR 92–273) to 83 (IQR 50–189) pg/mL.

Conclusions

In CKD patients, add-on PCT induces a significant reduction of proteinuria that is evident despite intensified anti-RAS therapy and larger in the presence of diabetes, higher GFR and unrestricted salt intake.

Keywords:
Angiotensin converting enzyme inhibitor; Angiotensin II receptor blocker; Renin inhibitor; Paricalcitol; Chronic kidney disease; Proteinuria