332 The Journal of Rheumatology 2007; 34:2 Personal non-commercial use only. The Journal of Rheumatology Copyright © 2007. All rights reserved. Renal Biopsy in Lupus Patients with Low Levels of Proteinuria LISACHRISTOPHER-STINE, MARK SIEDNER, JANICE LIN, MARK HAAS, HEMALPAREKH, MICHELLE PETRI, andDEREKM.FINE ABSTRACT. Objective. Early and accurate detection of kidney involvement in systemic lupus erythematosus (SLE) improves outcomes. Renal biopsy is required for definitive diagnosis of lupus nephritis (LN). In the absence of acute renal failure (ARF), moderate levels of proteinuria (> 1000 mg/24 h) have been rec- ommendedbysometojustifybiopsy.Weinvestigatedwhetherpatientswithlowerlevelsofproteinuria without ARF have significant renal disease and should be routinely biopsied. Methods. Weretrospectivelyevaluated21SLEpatientswith24-hurineprotein<1000mgwhounder- went kidney biopsies. Indications for biopsy included new-onset proteinuria, increasing proteinuria, or hematuria(>5redbloodcellsperhighpowerfield).NopatienthadARF. Results. Sixteen of 21 (77%) biopsies were diagnostic of LN: 3 class II, 10 class III (5 superimposed class V), 2 class IV (one superimposed class V), and one with class V. One patient had thrombotic microangiopathy. The remaining 4 (23%) patients had non-lupus renal disease. Thirteen patients with class III or greater LN required alterations in therapeutic regimen because of biopsy findings. Of 7 patientswithouthematuriaatthetimeofbiopsy,4(57%)hadclassIII,IV,orVLN.Onepatientwith- outhematuriaand<500mg/24hproteinuriahadclassIIILN. Conclusion. We found significant renal involvement (Class III, IV, or V LN) in SLE patients with <1000mgproteinuriawithorwithouthematuria.Ourfindingssuggestthatbiopsybestronglyconsid- ered in this patient population. (First Release Dec 15 2006; J Rheumatol 2007;34:332–5) Key Indexing Terms: SYSTEMICLUPUSERYTHEMATOSUS RENAL LUPUS NEPHRITIS PROTEINURIA BIOPSY From the Divisions of Nephrology and Rheumatology, Johns Hopkins University Department of Medicine, Baltimore, Maryland, USA. Dr. Christopher-Stine is supported by the Arthritis Foundation Postdoctoral Fellowship Award and The Johns Hopkins Clinician Scientist Career Development Award. The Johns Hopkins Lupus Cohort is supported by NIH AR43727 and the Johns Hopkins Clinical Research Center M-1-RR00052. L. Christopher-Stine, MD, MPH, Assistant Professor of Medicine; M. Siedner, MPH; J. C. Lin, BS; M. Haas, MD, Professor of Pathology; H.J. Parekh, MD; M. Petri, MD, MPH, Professor of Medicine; D.M. Fine, MD, Assistant Professor of Medicine. Address reprint requests to Dr. D.M. Fine, 1830 East Monument Street, Suite 416, Baltimore, MD 21205. E-mail: dfine1@jhmi.edu Accepted for publication August 23, 2006. Lupus nephritis (LN) is a common complication of systemic lupus erythematosus (SLE), occurring in up to 60% of affect- edadultsduringthecourseoftheirdisease 1 .Boththeclinical presentation and histopathological forms of kidney involve- ment are highly variable. The focal and diffuse forms of LN (classIIIandIV,respectively)generallypresentwithnephrit- ic urine sediments and may have progressive renal failure. In contrast, membranous nephritis (class V) typically presents with nephrotic-range proteinuria. Several studies, however, have illustrated the poor reliability of diagnoses rendered on thebasisofclinicalfeaturesalone 2-5 .Thus,renalbiopsyisan important tool in assessing patients with LN, and is often required for a definitive diagnosis of histopathological sub- type and direction of proper treatment. The decision to recommend renal biopsy can be complex. In the absence of acute renal failure, some physicians recom- mendbiopsyinthosewithproteinuria>500mg/24h 6 .Others have recommended biopsy only in patients with higher levels of proteinuria (> 1000 mg/24 h) and abnormal urine sedi- ment 7 . However, several case series have suggested that sig- nificantkidneydamagemayoccurinthesettingofactivepro- liferative LN without clinical signs of renal involvement 8,9 . Because early intervention is crucial to prevent poor out- comes 10,11 ,itisimperativethatkidneybiopsiesbeperformed so that diagnoses can be made and appropriate treatment initiated. We investigated whether SLE patients with levels of pro- teinuria<1000mg/24hshouldberoutinelybiopsiedtoaidin achieving earlier diagnoses and treatment of LN. MATERIALS AND METHODS Patients with SLE who underwent kidney biopsy after 1995 were included if at the time of biopsy they had a 24-h urine protein < 1000 mg or spot pro- tein:creatinine ratio < 1.0 (when 24-h collection had not been performed). Patients with a rise in creatinine > 0.2 mg/dl from baseline to biopsy date wereexcluded.ThebiopsieswereclassifiedaccordingtotheISN/RPSguide- lines 12 andwerescoredforactivityandchronicity 11 .Significantrenaldisease was defined as any classification of class III, IV, or V lupus nephritis or thrombotic microangiopathy. These diagnoses were thought likely to prompt www.jrheum.org Downloaded on April 20, 2021 from