Oral Calcitriol for the Treatment of Persistent Proteinuria in Immunoglobulin A Nephropathy: An Uncontrolled Trial
Received 20 August 2007; accepted 12 December 2007. published online 04 April 2008.
Refers to article:
Targeting Proteinuria as a Valid Surrogate for Individualized Kidney Protective Therapy
Dick de Zeeuw
American Journal of Kidney Diseases
May 2008 (Vol. 51, Issue 5, Pages 713-716) Full Text |
Full-Text PDF (94 KB)
Background
Laboratory research and previous retrospective study suggest that vitamin D and its analogues have profound effects on immune system function and glomerular mesangial cell proliferation. We conducted an open-label study to evaluate the antiproteinuric effect of calcitriol on proteinuria in patients with immunoglobulin A (IgA) nephropathy.
Study Design
Open-label prospective uncontrolled trial.
Setting & Participants
10 patients (3 men) with biopsy-proven IgA nephropathy and persistent proteinuria despite angiotensin-converting enzyme–inhibitor or angiotensin receptor blocker therapy in a tertiary referral center.
Intervention
Calcitriol, 0.5 μg, twice weekly for 12 weeks.
Outcome Measures
Changes in proteinuria, renal function, serum transforming growth factor β (TGF-β) and angiotensin II levels.
Results
After calcitriol treatment, there was a significant overall decrease in proteinuria with time by using a general linear model with repeated measures (P = 0.03). There was a progressive decrease in urine protein-creatinine ratio from 1.98 ± 0.74 to 1.48 ± 0.81 g/g (P = 0.007) during the first 6 weeks that persisted throughout the study period. No significant change in blood pressure or renal function was noted. There was a simultaneous decrease in serum TGF-β level, and percentage of decrease in serum TGF-β level significantly correlated with percentage of change in proteinuria (Spearman r = 0.643; P = 0.02). Serum angiotensin II level did not change throughout the study. One patient experienced transient hypercalcemia that normalized after a dosage decrease. No other major adverse effect was reported.
Limitations
This small study is uncontrolled and does not examine the long-term effect of calcitriol therapy.
Conclusion
Twice-weekly oral calcitriol has a modest antiproteinuric effect in patients with IgA nephropathy and persistent proteinuria despite angiotensin-converting enzyme–inhibitor or angiotensin receptor blocker therapy. Additional studies are needed to confirm the renal protecting effect of calcitriol in patients with chronic proteinuric kidney diseases.
Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
Address correspondence to Cheuk-Chun Szeto, MD, FRCP(Edin), Department of Medicine & Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
ABSTRACT