Continental variations in IgA nephropathy among Asians.

BACKGROUND/AIMS: Local variations in patient demographics and medical practice can contribute to differences in renal outcomes in patients with IgA nephropathy. We report the experiences of two groups of Asians with IgA nephropathy across continents.

MATERIALS AND METHODS: We retrospectively examined two cohorts of Asian patients with IgA nephropathy from The King Chulalongkorn Memorial Hospital registry, Thailand (1994 - 2005), and The Metropolitan Toronto Glomerulonephritis registry, Canada (1975 - 2006), and compared their baseline characteristics. Slope of estimated glomerular filtration rate (eGFR) in each group was approximated using separate repeated measures regression models for each country.

RESULTS: There were 152 Canadian and 76 Thai patients. At the time of first presentation, Thai patients were more likely to be female (63.2 vs. 44.1%, p = 0.01), have less baseline proteinuria (1.2 vs. 1.7 g/d, p = 0.08) and more likely to receive angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin receptor blockers (ARB) (64.0 vs. 15.2%, p < 0.01), or prednisone (41.3 vs. 4.6%, p < 0.01). The annual change in estimated glomerular filtration rate (eGFR) for the Thai and Canadian groups were -0.82 ml/min/1.73 m2/year and -3.35 ml/min/1.73 m2/year, respectively, after adjustment for age, sex, mean arterial pressure (MAP), proteinuria, body mass index, Haas histological grade, chronicity scores and baseline medications.

CONCLUSIONS: Although disease severity was similar among IgA nephropathy patients in Canada and Thailand, more Thai patients were on ACE-I/ARB or prednisone therapy at baseline. Further prospective research is needed to explore international differences in demographic and environmental factors, health resources, and disease management to determine how they may impact long-term outcomes in Asians with IgA nephropathy.