title: Sodium-lithium countertransport activity as a determinant of deterioration of glomerular function in IgA nephropathy.
abstract: We measured Na+/Li+ CT in 16 IgA nephropathy patients. Records were reviewed (mean observation period 5.5 years) for serial measurements of blood pressure (BP), urinary protein excretion, GFR (51Cr-EDTA) and plasma creatinine. Na+/Li+ CT correlated with the slope of the plot of GFR versus time (rs = -0.66, p = 0.005) systolic BP at diagnosis (rs = 0.62, p = 0.011) and both systolic and diastolic BP at the end of follow-up (rs = 0.69, p = 0.003, and rs = 0.56, p = 0.023). A diastolic blood pressure (DBP) > or = 95 mm Hg was associated with a faster rate of GFR decline (rate of change of GFR: -0.40 vs. -0.14 ml/min/month, p = 0.07; for DBP > or = 95 vs. < 95 mm Hg, respectively). In a multiple regression analysis with the rate of decline of GFR as dependent variable, Na+/Li+ CT emerged as a significant and independent determinant of the rate of fall of GFR (beta coefficient -1.56, SE beta 0.49, p = 0.006) and explained 52.7% of the variation in the GFR fall. Higher activities of Na+/Li+ CT are significantly associated with an increased rate of deterioration of renal function in IgA nephropathy; part of this effect could be mediated by higher blood pressure values.
authors.affiliation: Unit for Metabolic Medicine, Guy's Hospital, UMDS, London, UK.
authors.forename: P S
authors.initials: PS
authors.lastname: Kontessis
authors.forename: R
authors.initials: R
authors.lastname: Friedman
authors.forename: T
authors.initials: T
authors.lastname: Tariq
authors.forename: F
authors.initials: F
authors.lastname: Moro
authors.forename: D G
authors.initials: DG
authors.lastname: Williams
authors.forename: R B
authors.initials: RB
authors.lastname: Hartley
authors.forename: G C
authors.initials: GC
authors.lastname: Viberti
mesh_terms: D000293:Adolescent; D000328:Adult; D001693:Biological Transport, Active; D001794:Blood Pressure; D003404:Creatinine / Q000097:blood; D005260:Female; D005919:Glomerular Filtration Rate; D005922:Glomerulonephritis, IGA / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D007678:Kidney Glomerulus / Q000378:metabolism*; D008094:Lithium / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011507:Proteinuria / Q000503:physiopathology; D012189:Retrospective Studies; D012964:Sodium / Q000378:metabolism*
chemical_list: D008094:Lithium; D012964:Sodium; D003404:Creatinine