title: Kidney volume and function in autosomal dominant polycystic kidney disease.
abstract: BACKGROUND
  The significance of total kidney volume (TKV) as a biomarker of kidney function in autosomal dominant polycystic kidney disease (ADPKD) is controversial and has been reappraised.
  
  
  METHODS
  Between 2007 and 2012, 64 patients were followed with a mean 39.7-month observation period. TKV measurements by magnetic resonance imaging and estimation of renal function with estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease equation and 24-h urine creatinine clearance were repeated annually.
  
  
  RESULTS
  TKV and its adjusted parameters (height-adjusted, body surface area-adjusted and log-converted TKV [log-TKV]) correlated with eGFR significantly. Among them, the correlation coefficient of log-TKV was most significant (r = -0.6688, p < 0.001). The eGFR slope correlated negatively with TKV slope (p < 0.05). TKV increased faster and became larger as chronic kidney disease (CKD) stage advanced. As age advanced, eGFR declined significantly (p < 0.001), but the eGFR slope remained constant. There was no significant correlation between TKV and age, but the log-TKV slope became smaller as age advanced. If baseline TKV was large, the eGFR slope was steeper (p < 0.05), which suggests that eGFR declines faster in patients with larger kidney volume.
  
  
  CONCLUSIONS
  TKV is confirmed as a clinically meaningful surrogate marker in ADPKD. Log-TKV correlates with eGFR most significantly. Higher rates of kidney enlargement and larger kidney volume are associated with a more rapid decrease in kidney function. Kidney function decreased faster as CKD stage advanced, but its declining slope did not change significantly by age, at least after ~30 years of age.
authors.affiliation: Department of ADPKD Research, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan, ehigashi@ks.kyorin-u.ac.jp.
authors.forename: Eiji
authors.initials: E
authors.lastname: Higashihara
authors.forename: Kikuo
authors.initials: K
authors.lastname: Nutahara
authors.forename: Takatsugu
authors.initials: T
authors.lastname: Okegawa
authors.forename: Toshihide
authors.initials: T
authors.lastname: Shishido
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Tanbo
authors.forename: Kuninori
authors.initials: K
authors.lastname: Kobayasi
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Nitadori
mesh_terms: D000328:Adult; D000367:Age Factors; D015415:Biomarkers / Q000652:urine; D003404:Creatinine / Q000652:urine; D018450:Disease Progression; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000473:pathology* / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009929:Organ Size; D016891:Polycystic Kidney, Autosomal Dominant / Q000150:complications* / Q000473:pathology / Q000503:physiopathology / Q000652:urine; D011237:Predictive Value of Tests; D011379:Prognosis; D051436:Renal Insufficiency, Chronic / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology / Q000652:urine; D013997:Time Factors
chemical_list: D015415:Biomarkers; D003404:Creatinine