title: Variability in CKD stage in outpatients followed in two large renal clinics.
abstract: OBJECTIVE
  Chronic kidney disease (CKD) is staged by glomerular filtration rate (GFR). CKD stages sometimes vary between routine office visits, and it is unknown if this impacts renal and patient survival separately from a cross-sectional CKD stage value. We quantified and categorized CKD stage variability in a large group of outpatients and correlated this with clinical and demographic features and with renal and patient survival.
  
  
  METHODS
  All estimated GFRs were staged in the first observation period. CKD stages were then categorized as static, improving, worsening, or fluctuating. Logistic regression analysis was performed to identify clinical variables associated with CKD stage variability. Death and dialysis progression rates were then collected and analyzed using Cox proportional regression.
  
  
  RESULTS
  During a 1.1-year observation period, 1,262 patients (mean age 71.25 years) had a mean 5 eGFR's. CKD stages were static in 60.4%, worsened in 14.4%, improved in 7.4%, and fluctuated in 17.2% of patients. Secondary analysis revealed heavy proteinuria and East Asian ethnicity to be negatively, and diabetes mellitus and previous acute kidney injury to be positively associated with improving CKD stages. Cox proportional regression of 902 patients analyzed 2.3 years later revealed a negative association with improving CKD stage and subsequent need for dialysis.
  
  
  CONCLUSIONS
  CKD stage changed in 40% of 1,262 elderly patients when determined 5 times in just over 1 year. Improving CKD stage was the only variability pattern significantly associated with any of the clinical outcomes when assessed 2.3 years later, being unlikely to be linked with subsequent need for dialysis.
authors.affiliation: Renal Division, Scarborough Hospital, Scarborough, ON, Canada. tabosikaneta@yahoo.ca
authors.forename: Tabo
authors.initials: T
authors.lastname: Sikaneta
authors.forename: Mohamed
authors.initials: M
authors.lastname: Abdolell
authors.forename: Hulya
authors.initials: H
authors.lastname: Taskapan
authors.forename: Janet
authors.initials: J
authors.lastname: Roscoe
authors.forename: Jason
authors.initials: J
authors.lastname: Fung
authors.forename: Gordon
authors.initials: G
authors.lastname: Nagai
authors.forename: Robert H
authors.initials: RH
authors.lastname: Ting
authors.forename: Paul
authors.initials: P
authors.lastname: Ng
authors.forename: George
authors.initials: G
authors.lastname: Wu
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Oreopoulos
authors.forename: Paul Y
authors.initials: PY
authors.lastname: Tam
mesh_terms: D058186:Acute Kidney Injury / Q000503:physiopathology; D000368:Aged; D000554:Ambulatory Care Facilities; D044466:Asian People; D003928:Diabetic Nephropathies / Q000503:physiopathology; D005919:Glomerular Filtration Rate; D006801:Humans; D016015:Logistic Models; D016017:Odds Ratio; D009864:Ontario; D016016:Proportional Hazards Models; D011507:Proteinuria / Q000503:physiopathology; D051436:Renal Insufficiency, Chronic / Q000145:classification* / Q000503:physiopathology*; D012189:Retrospective Studies