Enzyme replacement therapy together with renin-angiotensin system inhibition seems to prevent kidney function decrease in most Finnish Fabry patients treated either for 5 or 10 years

Enzyme replacement therapy (ERT) has stabilized renal function but its effect on proteinuria is inconsistent. Also nephroprotective renin-angiotensin-aldosterone system (RAAS) inhibition is warranted. We calculated eGFR using CKD-EPI formula and albuminuria using urine albumin/creatinine ratio (ACR) once a year in 12 Fabry patients with ERT for 10 years (8 females, 4 males, age 53.6 (15.0) years) and in 24 patients with ERT for 5 years (11 females, 13 males, 53.3 (17.2) years). In the 10-year group 5 patients and in the 5-year group 12 patients used RAAS inhibition at the end of follow-up. General linear model for repeated measures and Pearson correlation were used. Two patients who got renal transplantation were excluded. EGFR decreased 5.0 (SD 15.3, median 5.0) ml/min/1.73 m2, slope -0.5/year in the 10-year group and increased 0.7 (SD 9.2, median -2.2), slope +0.14/year in the 5-year group. No statistically significant change was seen in either group. ACR increased 2.5 (SD 6.7, median 0.07) mg/mmol, slope 0.25/year in the 10-year group and 1.3 (SD 4.6, median 2.2) mg/mmol, slope 0.26/year in the 5-year group. No statistically significant change was seen in either group. In the 10-year group eGFR decreased more than 15 ml/min/1.73 m² in 4 patients and in the 5-year group in one patient. ACR increased over 5 mg/mmol in 2 patients both in the 10-year and in the 5-year group. Neither age, age at the initiation of ERT, gender, use of agalsidase alfa versus beta nor use of RAAS inhibitor correlated to change in eGFR or ACR in the 10-year group. In the 5-year group, higher age correlated to higher change in eGFR (p=0.024). According to our results, ERT for five years regardless of RAAS inhibition prevented decline in kidney function. This finding was more consistent with younger age, suggesting earlier initiation of ERT.