#67: Chronic Kidney Disease Pearls with @kidney_boy, Joel Topf

November 13, 2017 | By Justin Berk

Take control of chronic kidney disease with tools, and tips from @kidney_boy, Joel Topf, MD Salt Whisperer and Chief of Nephrology at Kashlak Memorial Hospital. Learn which equation is best for eGFR, how to counsel patients about progression/prognosis, how to monitor patients in CKD, and who needs a referral to Nephrology. Special thanks to Annie Medina, and Justin Berk for writing/producing this show and to physician-artist, Kate Grant for her lovely and hilarious artwork (more at paintscientific.com).

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Case from Kashlak Memorial: Donald is a 56 year old African American gentleman with heart failure, hypertension, diabetes, and chronic kidney disease been seen as a new patient. He doesn’t take any medications as he just recently got his insurance back. Shoutout to Kashlak social work team! His creatinine today is 1.7, which seems to be his baseline.

Clinical Pearls:

1. What equation should be used to estimate GFR? CKD-Epi. Based on largest population of any calculator. Best for “normal sized people.”
2. 24 hour urine creatinine clearance equation works for all patients regardless of size e.g. bodybuilder, or amputee. Can be corrected for body surface area (click link) [Urine Cr (mg/dl) * Urine volume (ml)] / [Plasma Cr (mg/dl) * Time (min)] = CrCl
3. How does age affect GFR? Controversial – adults are expected to lose approximately 1 ml/year of GFR past age 40.
4. Recommended workup for new diagnosis of CKD:
   • Urinalysis: Quantify proteinuria
   • Diabetic nephropathy gradually increases proteinuria (takes years)
   • Glomerulonephritis rapidly increases proteinuria
   • Urine Albumin-to-creatinine misses multiple myeloma Bence-Jones proteins; instead use protein-to-creatinine ratio.
   • Urine dipstick only tests for albumin, not globulin fraction of protein
   • Consider biopsy if significant proteinuria and no history of diabetes
   • Ultrasound: A low yield test but may catch treatable problems e.g. athlerosclerotic disease, tumor, obstruction
5. Staging of CKD
   •  Kidney Heatmap for Staging
   • Kidney Failure Risk calculator (estimated 2 and 5 year risk of needed dialysis)
      Based on Tangri et al, JAMA 2016
6. Refer patients if:
   • You feel uncomfortable
   • Persistent hematuria
   • eGFR < 30
   • Significant proteinuria (>2gm/day)
   • Uncontrolled hypertension
7. Monitoring of patients w/CKD:
8. CKD 3: Twice yearly visits for urinalysis (UA), urine albumin:creatinine ratio (ACR)
9. CKD 4:  Four times yearly visits for UA, ACR, plus annual hemoglobin, PTH
10. Low protein diet in CKD is controversial: UpToDate suggests possible benefit, but many Nephrologists (like Dr Topf) disagree with this interpretation of the data. Read this for more insight 
11. Most common form of anemia is iron (Fe) deficiency, not Epo deficiency elevated hepcidin → poor iron absorption, patients may need IV iron
12. Treating secondary hyperparathyroidism lacks evidence for clinical outcomes like fracture. Consider therapy w/activated vitamin D if PTH level rising >150-200 consistently due to development of treatment resistance w/symptoms of bone pain, itching, fractures

Goal: Listeners will gain a better understanding of the diagnosis and management of chronic kidney disease and the associated complications

Learning objectives:
After listening to this episode listeners will…

1. Diagnose and risk stratify chronic kidney disease
2. Perform an initial workup and evaluation for new patient with CKD
3. Identify possible interventions (pharmacological, dietary, and other) to slow CKD progression
4. Utilize formulas to estimate GFR and Creatinine Clearance.
5. Explain CKD to patients and counsel them on prognosis
6. Identify the secondary complications caused by CKD and how to address them
7. Identify patients who need a referral to nephrology

Disclosures: Dr Topf lists the following disclosures on his website:

“I am on the speakers bureau for Astute Medical. I have an ownership stake in four Davita run dialysis clinics and one vascular access center. Astellas paid for my trip to Australia (Feb ’15) for me to speak at one meeting and three hospitals. Takeda Oncology made a donation to MM4MM the program that is taking me to Mount Everest in 2018.”

Time Stamps

• 00:00 Intro
• 03:13 Pick of the weeks
• 08:49 Clinical Case
• 09:36 How to explain CKD to patients
• 12:16 Loss of GFR with age
• 13:22 Which equation should be used to estimate GFR
• 18:05 Creatinine clearance from 24 hour urine collection
• 22:25 Initial workup upon diagnosis of CKD
• 25:40 Interpreting tests for proteinuria
• 26:52 Staging and prognosis in CKD
• 32:00 Completing the initial workup for CKD
• 33:52 Who needs a referral to nephrology?
• 35:53 What labs to check in CKD and a discussion of secondary hyperparathyroidism
• 40:32 Take home points
• 42:30 Outro

Links from the show:

1. Follow @kidney_boy on Twitter
2. Check out Dr Topf’s Precious Bodily Fluids blog
3. Mata Tea Gourd
4. Citations Needed Podcast
5. TED Radio Hour: Manipulation episode
6. JAMA Article on oral semaglutide
7. Creatinine Clearance calculator from Cornell Med
8. Low protein diet for CKD probably ineffective https://ajkdblog.org/2017/03/07/nephmadness-2017-nutrition-region/amp/

Other resources:  Check out Joel Topf’s slide deck from a recent Nephrology Update 2017 talk