Kidney Disorders Community

I know that "48" sounds scary, but only if you think in terms of a 0%-100% scale; the problem is that GFR is not actually measured on a scale of percentages. It's measured as ml/min/1.72 m squared. It's just the way that the system has developed and changed over the decades.

So really, anything over 60 is considered negligible and rarely even gets noted on a lab report. And it always declines slowly as we age, even for perfectly healthy folks.

You also need to take into account that most of these tests these days are actually eGFR, e meaning "estimated" and this is calculated only from blood test numbers. The REAL way that the test was originally does took into account the blood numbers, urine output (hence the 'ml/min' part of it, and body surface area (that is the 1.72 meters squared part of it). And the eGFR accounts for neither of these very well. But it is cheap and fast so that's why the eGFR gets used in place of the tedious and expensive way to calculate true GFR.

All that said, 48 probably isn't perfect function, and the 1.2 mg/dL serum creatinine could be better. But it isn't immediately dangerous. What you don't want is for that number to continue sliding steadily over the years and decades. If it is stable at about 1.2 for a few years it is less worrisome; if it is changing a few decimal points every year then that needs attention. These numbers can jump around a bit from one test to the next, so you need to watch the long term trend.

Yes, overweight does tend to stress the kidneys a bit, but the bigger concern is overall cardiovascular health: kidneys are the most blood-hungry organs in the body, and when they sense a threat to their blood supply, they elevate blood pressure, and eventually the tiny nephrons start dying off (and the never will come back).

Use your best judgment, but anything that is heart healthy is kidney healthy in the long run.