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Your Good Health: Drop in patient's kidney function score not a concern

It is normal for the eGFR or estimated glomerular filtration rate to decrease slowly after the age of 18
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Dr. Keith Roach

Dear Dr. Roach: I am a 73-year-old female. A recent blood test returned an eGFR (estimated glomerular filtration rate) of 59. My physician’s nurse told me that the test was normal. When I asked her about the eGFR, she said that she didn’t know what that was, but the doctor said that the results were normal. The score last year was 67. Should I follow up on this?

C.C.

The eGFR is a reflection of kidney function. The higher the number, the more effective the kidney is at removing waste products from the blood. The normal range is different for men compared to women and depends strongly on age, with the eGFR normally decreasing slowly after the age of 18. The median result for a 73-year-old woman without kidney disease is 64, with 90% of healthy women falling somewhere between an eGFR of 49 and 85.

An eGFR is estimated by the creatinine level in the blood. Creatinine can go up and down a little bit depending on diet, activity and fluid intake, so a single reading shouldn’t be used to make final decisions. Since you are right about being in the normal range, I’m not too concerned. The drop might just be the result of normal variability, but periodically checking is appropriate here.

Many of my patients got very concerned when the lab started reporting any result below 60 as chronic kidney failure, but interpreting the results requires the consideration of age and sex.

Dear Dr. Roach: Regarding the recent letter from the man with benign prostatic hyperplasia (BPH), who does not like the side effects of his prescribed drugs, you could suggest that he try tadalafil. Like him, I could not tolerate the side effects of drugs like tamsulosin, but I don’t get any side effects with 5 mg of tadalafil. It has reduced my urination frequency by at least half. Tadalafil is now available as a generic brand, which costs less.

A.M.

I appreciate your writing. Tadalafil, designed for use as an erectile dysfunction drug, is effective for many men with enlarged prostate symptoms. I was surprised to see that the generic brand only costs about $10 per month in my area using GoodRx.com, and it is covered by many insurances for use in the treatment of BPH.

Dear Dr. Roach: I have received sacroiliac joint injections for about four years, following a modification of my lumbar fusion. I now have a blood clot in my right calf, so I was wondering if this is related to the procedure or if it is just coincidental.

One of the doctors made a statement that this injection can sometimes cause a blood clot to form below the knee at the rear of the calf, but after speaking to two other doctors, they said that they never heard of this happening. What is your opinion?

J.L.T.

I reviewed a lot of studies on sacroiliac joint injections, and although some mention blood clotting as a risk, I was unable to find any evidence of an increased risk of blood clotting. However, people who aren’t getting up and walking for any reason, including after a medical procedure, are at a higher risk for blood clotting, so it’s important to move right away following the injection. Your doctor can also consider medication to reduce the risk of blood clots.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu