Glomerular Filtration Rate Trends During Follow-up in Children With Steroid-Sensitive Nephrotic Syndrome.

BACKGROUND

Overall prognosis of children with steroid-sensitive nephrotic syndrome (SSNS) is regarded as generally favorable. However, only a few recent studies have evaluated changes in kidney function and blood pressure over time in children with SSNS.

OBJECTIVES

We describe clinical features of SSNS patients and characterize changes in calculated estimated glomerular filtration rate (eGFR) and use of antihypertensive medications during follow-up.

DESIGN

This is a retrospective cohort study.

SETTING

This study was conducted in a Canadian pediatric nephrology center.

PATIENTS: This study included patients aged 1 to 18 years with SSNS.

MEASUREMENTS: eGFR was calculated from recorded serum creatinine and height measurements using the modified Schwartz equation.

METHODS

eGFR was calculated at yearly intervals, and the trend of eGFR was assessed using linear mixed effects model. Patients were also evaluated for use of antihypertensive medications during follow-up.

RESULTS

Seventy-eight patients-median age, 3.2 years (interquartile range [IQR], 2.65) and median follow-up of 4.37 (IQR, 5.6)-were evaluated. Sixty-three (80.8%) had at least 1 relapse. Twenty-two (28.2%) and 20 (25.6%) were steroid dependent and frequently relapsing, respectively. Forty-three patients (55.1%) received at least 1 steroid-sparing agent, and of these, 18 (41.8%) received a calcineurin inhibitor. One patient had eGFR ≤90 mL/min/1.73 m2 during observation. eGFR remained unchanged over the follow-up period in this cohort of patients. Four patients (5.1%) were on antihypertensive medications at the end of follow-up.

LIMITATIONS: Patients who had frequent relapses had more measurements available for serum creatinine and height, creating a sampling bias. The number of eGFR measurements was overall small, making it difficult to ascertain eGFR trend.

CONCLUSION

eGFR remained unchanged over time in this cohort, and a small proportion of patients required antihypertensive therapy at the end of follow-up. Our study highlights the needs for carefully constructed long-term observational studies of children with nephrotic syndrome.