Bazile.....knowing you, you will obviously "trawl" the websites...;-)
Let me give you it quite simply.
There are five stages of kidney disease 1-5, depending upon your Kidney Filtration rate. called CKD (chronic kidney disease )
https://www.kidney.org/atoz/content/gfr
Stage 1......great kidneys
Stage 5.....2.30 at the crematorium.
Get the picture?
You are stage 3a...CKD......no big deal despite what the website says.
Knowing your history, that result would not be a cause for your persistent hypertension. At a guess I would say that 50% of the population over 70 years of age would have a CKD staging of Stage 3. no big deal.
Is that quite clear Bazile?