From the Guidelines
An 18% change in kidney function is not considered normal and may indicate an underlying kidney problem. This level of change is significant, especially if it occurs over a short period, as kidney function naturally declines with age at a rate of about 0.5-1% per year after age 40 1. According to the 2014 study published in the American Journal of Kidney Diseases, the mean annual decline in eGFR found in individuals with CKD was less than 5 mL/min/1.73 m2 per year, which is equivalent to a percentage change of less than 10% per year for someone with a baseline GFR of 50 mL/min/1.73 m2 1. The commentary work group agrees that a definition based on percentage reduction of eGFR will differ across starting levels of eGFR and the duration of time over which the changes occur, and a 25% reduction in eGFR is considered a substantial loss of kidney function if it occurred over a relatively short time 1. Some key points to consider include:
- The rate of decline in kidney function can vary depending on the underlying cause and individual factors, such as age, baseline kidney function, and presence of comorbidities like hypertension or diabetes 1.
- Certain medications, dehydration, infections, and uncontrolled high blood pressure or diabetes can also impact kidney function, and early intervention is important to prevent permanent kidney damage 1.
- If you've had a test showing an 18% decline in kidney function, you should consult with your healthcare provider promptly to determine the cause and appropriate course of action, which may include follow-up testing, medication adjustments, or lifestyle changes 1.
From the Research
Kidney Function Change
- The provided studies do not directly address the normal range of kidney function change, but they do discuss the potential nephrotoxic effects of certain medications on kidney function 2, 3, 4.
- A study published in 2021 found that patients exposed to at least one potential nephrotoxin experienced a higher incidence of renal replacement therapy and acute kidney injury 2.
- Another study from 1990 found that concomitant therapy with ACE inhibitors and NSAIDs can synergistically compromise renal function, leading to reversible renal failure in some cases 3.
- A 2002 study discussed the adverse changes in renal function associated with NSAID therapy, including changes in electrolyte homeostasis and impaired renal perfusion 4.
Normal Kidney Function Change
- There is no direct evidence in the provided studies to determine if an 18% change in kidney function is normal.
- The studies focus on the potential nephrotoxic effects of certain medications rather than establishing a normal range for kidney function change.
- Further research would be needed to determine the normal range of kidney function change and whether an 18% change is within that range.