title: Comorbid renal tubular damage and hypoalbuminemia exacerbate cardiac prognosis in patients with chronic heart failure.
abstract: BACKGROUND
  Renal tubular damage (RTD) and hypoalbuminemia are risks for poor prognosis in patients with chronic heart failure (CHF). Renal tubules play a pivotal role in amino acid and albumin reabsorption, which maintain serum albumin levels. The aims of the present study were to (1) examine the association of RTD with hypoalbuminemia, and (2) assess the prognostic importance of comorbid RTD and hypoalbuminemia in patients with CHF.
  
  
  RESULTS
  We measured N-acetyl-β-D-glucosamidase (NAG) levels and the urinary β2-microglobulin to creatinine ratio (UBCR) in 456 patients with CHF. RTD was defined as UBCR ≥ 300 μg/g or NAG ≥ 14.2 U/g. There were moderate correlations between RTD markers and serum albumin (NAG, r = -0.428, P < 0.0001; UBCR, r = -0.399, P < 0.0001). Multivariate logistic analysis showed that RTD was significantly related to hypoalbuminemia in patients with CHF. There were 134 cardiac events during a median period of 808 days. The comorbidity of RTD and hypoalbuminemia was increased with advancing New York Heart Association functional class. Multivariate Cox proportional hazard regression analysis showed that the presence of RTD and hypoalbuminemia was associated with cardiac events. The net reclassification index was significantly improved by adding RTD and hypoalbuminemia to the basic risk factors.
  
  
  CONCLUSIONS
  Comorbid RTD and hypoalbuminemia are frequently observed and increase the risk for extremely poor outcome in patients with CHF.
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, Japan.
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Otaki
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, Japan. tewatana@med.id.yamagata-u.ac.jp.
authors.forename: Tetsu
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Funayama
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kinoshita
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, Japan.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Yokoyama
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Takahashi
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nishiyama
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Arimoto
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Shishido
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Miyamoto
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, Japan.
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Konta
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Kubota
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D002908:Chronic Disease; D003404:Creatinine / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D034141:Hypoalbuminemia / Q000150:complications*; D007674:Kidney Diseases / Q000150:complications* / Q000503:physiopathology; D007684:Kidney Tubules / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors
chemical_list: D015415:Biomarkers; D003404:Creatinine
keywords: Cardiac prognosis; Heart failure; Hypoalbuminemia; Renal tubular damage