title: Effect of primary care physicians' use of estimated glomerular filtration rate on the timing of their subspecialty referral decisions.
abstract: BACKGROUND
  Primary care providers' suboptimal recognition of the severity of chronic kidney disease (CKD) may contribute to untimely referrals of patients with CKD to subspecialty care. It is unknown whether U.S. primary care physicians' use of estimated glomerular filtration rate (eGFR) rather than serum creatinine to estimate CKD severity could improve the timeliness of their subspecialty referral decisions.
  
  
  METHODS
  We conducted a cross-sectional study of 154 United States primary care physicians to assess the effect of use of eGFR (versus creatinine) on the timing of their subspecialty referrals. Primary care physicians completed a questionnaire featuring questions regarding a hypothetical White or African American patient with progressing CKD. We asked primary care physicians to identify the serum creatinine and eGFR levels at which they would recommend patients like the hypothetical patient be referred for subspecialty evaluation. We assessed significant improvement in the timing [from eGFR < 30 to ≥ 30 mL/min/1.73m(2)) of their recommended referrals based on their use of creatinine versus eGFR.
  
  
  RESULTS
  Primary care physicians recommended subspecialty referrals later (CKD more advanced) when using creatinine versus eGFR to assess kidney function [median eGFR 32 versus 55 mL/min/1.73m(2), p < 0.001]. Forty percent of primary care physicians significantly improved the timing of their referrals when basing their recommendations on eGFR. Improved timing occurred more frequently among primary care physicians practicing in academic (versus non-academic) practices or presented with White (versus African American) hypothetical patients [adjusted percentage(95% CI): 70% (45-87) versus 37% (reference) and 57% (39-73) versus 25% (reference), respectively, both p ≤ 0.01).
  
  
  CONCLUSIONS
  Primary care physicians recommended subspecialty referrals earlier when using eGFR (versus creatinine) to assess kidney function. Enhanced use of eGFR by primary care physicians' could lead to more timely subspecialty care and improved clinical outcomes for patients with CKD.
authors.affiliation: Division of General Internal Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA. rfcharle@jhmi.edu
authors.forename: Raquel C
authors.initials: RC
authors.lastname: Greer
authors.forename: Neil R
authors.initials: NR
authors.lastname: Powe
authors.forename: Bernard G
authors.initials: BG
authors.lastname: Jaar
authors.forename: Misty U
authors.initials: MU
authors.lastname: Troll
authors.forename: L Ebony
authors.initials: LE
authors.lastname: Boulware
mesh_terms: D003404:Creatinine / Q000097:blood*; D005919:Glomerular Filtration Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*; D058007:Physicians, Primary Care / Q000706:statistics & numerical data*; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D012017:Referral and Consultation / Q000706:statistics & numerical data*; D013997:Time Factors; D014481:United States / Q000453:epidemiology
chemical_list: D003404:Creatinine