SUN-014 EPIDEMIOLOGY OF GLOMERULONEPHRITIS IN SOUTHEAST ASIA: THE GN-SPECIAL (GLOMERULONEPHRITIS – SINGAPORE-PHILIPPINES EPIDEMIOLOGY COHORTS IN ADULTS) STUDY

Abstract

Glomerulonephritides (GN) remain a leading cause of end-stage kidney disease in Southeast Asia and around the world. Studies examining epidemiological trends and clinical differences in GN in this region are lacking. We aim to evaluate the epidemiology, demographic trends and clinical features of renal histopathological frequencies in Singapore and the Philippines. We performed a cross-sectional study, examining all patients (older than 16 years old) with kidney biopsies showing GN diagnoses performed at the National Kidney and Transplant Institute, Philippines (2006-2015) and Tan Tock Seng Hospital, Singapore (2002-2016). We described and compared the frequency and clinical feature of each GN diagnosis, of primary nephrotic/nephritic syndrome subtypes, followed by age and gender stratification in the two countries. 5158 patients are included in the study, of which 4163 are from the Philippines and 995 are from Singapore. The patients in the Philippines are younger [mean age 36.7±13.7 years vs 46.7±17.5 years (p<0.001)]. The proportion of male patients are similar (44.0% vs. 46.0% in the Philippines and Singapore respectively, p= 0.25). In the Philippines, the three most common glomerular diseases are IgA Nephropathy (IgAN) (34.4%); focal segmental glomerulosclerosis (FSGS) (16.0%) followed by lupus nephritis (LN) (9.9%). On the other hand, in Singapore, these were LN (20.4%); IgAN (17.2%) followed by diabetic glomerulosclerosis (DG) (10.9%). Primary nephrotic syndrome [minimal change disease (MCD), FSGS and membranous nephropathy (MN)] is more common in patients from the Philippines (21.5% vs 17.4%, p=0.004), with patients from the Philippines being younger (38.9±14.6 years vs 54.2±17.8 years, p<0.001). In addition, IgAN is more prevalent in patients from the Philippines (34.4% vs 17.3%, p<0.001), with patients from the Philippines being younger (35.0±11.8 years vs 40.0±15.6 years, p<0.001) and having lower serum creatinine at biopsy (174.0±169.1 umol/L vs 226.7±297.9 umol/L, p<0.001). Conversely, LN is more common in patients from Singapore (20.5% vs 9.9%, p<0.001), with patients from the Philippines being younger (30.8±11.0 years vs 36.8±12.1 years, p<0.001) and having lower serum creatinine at biopsy (112.3±97.8 umol/L vs 171.8±178.0 umol/L, p<0.001). Interestingly, biopsy-proven DG is more common in Singapore (10.9% vs 2.0%, p<0.001) and infection-related glomerulonephritis (IRGN) is similar in frequency in both countries (Philippines 0.6% vs Singapore 0.7%, p=0.72). In this study involving two large-scale renal biopsy cohorts, we identified significant epidemiological differences on the distribution of GN in Philippines and Singapore. Patients with IgAN and LN have worse renal function at presentation in Singapore and the Philippines respectively, and could be due to genetic or environmental influences. The differences in DG may reflect biopsy practices and healthcare resourcing disparities. Despite socioeconomics and healthcare infrastructure differences in both countries, the incidence of biopsy-proven IRGN appear to be similar.