Fabry: Renal Function During Long-term ERT by 51Cr-EDTA Clearance

Nephropathy is common in Fabry disease (FD). Renal function decline is often the first sign of major organ involvement, sometimes progressing to end-stage renal failure. Available studies of renal function during enzyme replacement therapy have shown inconsistent results, and are based on different composition of patient materials and follow-up time.

Most investigations have used estimated glomerular filtration rate (eGFR) for evaluating renal function. GFR is an important indicator of renal function. eGFR based on a serum creatinine measurement is most commonly used in FD. However, this method has been shown to be unreliable, as serum creatinine levels are influenced by other factors than renal function such as ethnic group, muscle mass, age, hydration and diet. Performance of eGFR in detecting minor changes in renal function is poor. A 10 year old review on renal function evaluation in patients with FD recommended the use of GFR based on an exogenous marker, e.g. Cr-EDTA. Nevertheless, only few studies have used mGFR for evaluation of renal function and to our knowledge, the present study is the first to describe the rate of renal function decline with consecutive mGFR values in a nationwide population of patients with FD.

Renal function declines with age in renal healthy individuals. To our knowledge, the present study is the first to age-standardize renal function in patients with FD to adjust for age-dependent renal deterioration.

Inclusion criteria

• Genetically and/or enzymatically verified Fabry disease

Exclusion criteria

• End-stage renal disease prior to baseline (GFR <15 ml/min/1.73m2, dialysis or renal transplant)
• Patient has not received enzyme replacement therapy during follow-up
• Patient has had less than 3 measurement of GFR during follow-up