title: Symmetric dimethylarginine (SDMA) as endogenous marker of renal function--a meta-analysis.
abstract: BACKGROUND
  Dosing of most drugs must be adapted in renal insufficiency, making accurate assessment of renal function essential in clinical medicine. Furthermore, even modest impairment of renal function has been recognized as a cardiovascular risk factor. The purpose of this analysis was to identify the role of symmetric dimethylarginine (SDMA), the structural isomer of the cardiovascular risk marker asymmetric dimethylarginine, as an endogenous marker of renal function.
  
  
  METHODS
  Comprehensive searches of Medline and the Cochrane Library from 1970 to February 2006 were performed to identify studies that evaluated the correlation between SDMA and renal function. The search was augmented by scanning references of identified articles and reviews. The correlation coefficients (R) were recorded from each study for the values of 1/SDMA and clearance estimates and for SDMA and creatinine levels. The summary correlation coefficients with 95% confidence intervals (CIs) were pooled using the random-effects method.
  
  
  RESULTS
  In 18 studies involving 2136 patients systemic SDMA concentrations correlated highly with inulin clearance [R = 0.85 (CI 0.76-0.91, P < 0.0001)], as well as with various clearance estimates combined [R = 0.77 (CI 0.65-0.85, P < 0.0001)] and serum creatinine [R = 0.75 (CI 0.46-089, P < 0.0001)].
  
  
  CONCLUSIONS
  SDMA exhibits some properties of a reliable marker of renal function. Future studies have to clarify whether SDMA is indeed suited to improve diagnosis and eventually optimize care of patients.
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305-5406, USA. Kielstein@yahoo.com.
authors.forename: Jan T
authors.initials: JT
authors.lastname: Kielstein
authors.forename: Shelley R
authors.initials: SR
authors.lastname: Salpeter
authors.forename: Stefanie M
authors.initials: SM
authors.lastname: Bode-Boeger
authors.forename: John P
authors.initials: JP
authors.lastname: Cooke
authors.forename: Danilo
authors.initials: D
authors.lastname: Fliser
mesh_terms: D001120:Arginine / Q000031:analogs & derivatives* / Q000097:blood; D015415:Biomarkers / Q000097:blood; D002318:Cardiovascular Diseases / Q000097:blood / Q000209:etiology; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D007444:Inulin / Q000378:metabolism; D008297:Male; D011379:Prognosis; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000150:complications; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D015415:Biomarkers; C487735:dimethylarginine; D007444:Inulin; D001120:Arginine; D003404:Creatinine