By Dr. Salim Rezaie
Recently, I read an article on some very useful chronic kidney disease (CKD) pearls to help
those healthcare providers who are not nephrologists care for their patients and also prepare
for the ABIM Internal Medicine Board exam at the same time. The article was titled “The Top
10 Things Nephrologists Wish Every Primary Care Physician Knew” by Paige NM et al and
basically stated: early recognition of kidney disease is essential in order to begin
measures to prevent progression and complications such as kidney failure,
cardiovascular disease, and premature death. I have decided to break the content into two
parts; the first half will be discussed in this post:
Pearl # 1: A “Normal” Creatinine Level May Not Be Normal
Make sure to take muscle mass, age, sex, height, and limb amputation into account
Consider using MDRD or Cockcroft-Gault equations to calculate glomerular filtration
rate (GFR)
MDRD and Cockcroft-Gault equations are imprecise at high values for GFR (low values
for serum creatinine)
Pearl # 2: Know the Medications That Falsely Elevate Serum Creatinine Levels
Trimethoprim-sulfamethoxazole and cimetidine decrease secretion of creatinine
Both medications can increase creatinine level by as much as 0.4 – 0.5mg/dL
An increase in creatinine level is a true decrease in GFR only if there is also a
corresponding increase in BUN
Pearl # 3: Patients with Decreased GFR or Proteinuria Need to be Evaluated for the