Post-streptococcal glomerulonephritis: Some reduction in a disease of disparities.

AIM: A retrospective Auckland-wide (total population approximately 1.4 million) study of hospital admissions from 2007 to 2015 was conducted to assess trends in admissions for acute post-streptococcal glomerulonephritis (APSGN) in children aged 0-14 years.

METHODS: International Statistical Classification of Diseases (ICD10) discharge codes were used to identify potential cases of APSGN, and electronic clinical records and laboratory data were compared with established case definitions for definite or probable APSGN.

RESULTS: A total of 430 cases of APSGN were identified (definite n = 337, probable n = 93), with a mean annual incidence of 15.2/100 000 (95% confidence interval (CI) 14.9-15.6). Incidence (0-14 years) was 17 times higher in Pacific peoples (50.2/100 000, 95% CI 48.6-51.8) and almost 7 times higher in Māori (19.6/100 000, 95% CI 18.6-20.7) than European/other populations (2.9/100 000, 95% CI 2.7-3.1). Multivariate analysis found ethnicity, deprivation, male gender, age (peak 3-8 years) and season (summer/autumn) to be associated with admission risk. Admission rates showed a significant change of -9.0% (95% CI -10.4, 7.4%) per year, with 2011 being an exception. Low C3 complement, hypertension, elevated streptococcal titres, oedema and heavy proteinuria were present in 94, 65, 67, 52 and 49% of cases, respectively. Relying on ICD10 codes without further review of clinical notes would result in an overcount of cases by 25%.

CONCLUSIONS: There is severe disparity in APSGN admission rates, with a disproportionate burden of disease for Pacific and Māori children and those living in deprived circumstances. Rates trended downward from 2007 to 2015.