u/Snaphappy3

I just want to share how important proper hydration is to getting an accurate eGFR test result. It took me by surprise even though I already thought I knew all about the importance of drinking lots of water and flushing the kidneys.

My eGFR had remained stable for years despite persistent proteinuria and hematuria, however it recently dropped from 88 in Aug 2025 to 69 in April of 2026, which was a bit of a surprise but not super concerning, however it was the first time I had ever seen a fluctuation that large.

A subsequent test in July 2026 saw it rebound back up to 77 for which I experienced relief, but it wasn't in the 80's anymore and I thought "well I guess I've having some decline, but nothing serious and for my age at 62 not too bad." I was prepared to accept that my eGFR would not stay high permanently with my condition, but the decline was slow enough to make me feel that I was one of the lucky ones.

But then another test in September in association with me feeling ill having low energy, weight loss and various other symptoms provided a new result of an eGFR of 61. Now I was getting a bit more concerned but rationalized that it's still in the normal range and it's still not too bad. But I still had a niggling worry at seeing my numbers drop from from 88 o 61 in one year.

Because I had come in with the concern about my feeling of malaise, the doctor wanted to recheck my blood work in a couple of weeks and recommended I drink plenty of water and stay hydrated before the test. He suspected I may have been dehydrated from whatever was making me feel so bad, and wanted to follow up.

Well to my surprise and to his credit, he was right. I drank around a liter and a half of water in the 2 hours leading up to my bloodwork and the result was a new eGFR number of 82. My creatinine number also dropped significantly as well, back into the normal range from 113 umol/L to 88.

It turns out that the most likely explanation may have been when I switched to chlorthalidone from hydrochlorothiazide about a year ago. Apparently chlorthalidone is a more powerful diuretic than HCTZ and my hydration habits under HCTZ were obviously insufficient under chlorthalidone.

In any case this was a huge learning by experience moment for me, and I hope you all drink lots of water in general, but particularly before you get any bloodwork. Sometimes a major drop in eGFR can be from something as simple as that and nothing to worry about.

Curious if anyone has any experience with using chlorthalidone to treat proteinuria? My doctor took me off Farxiga today as it had no impact on the protein spillage after an 8 month trial. In fact my eGFR fell from 88 to 69 during this period. My ACR didn't move and urine protein increased, so she changed my meds to Chlorthalidone and cancelled me taking Hydrochlorothiazide. In addition to this, I am also on Ramipril and Amlodipine for hypertension.

I had high hopes for Farxiga but it looks like it isn't helping me. Just curious if anyone has had positive results on chlorthalidone?