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 Maori (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 Maori children and those living in deprived circumstances. Rates trended downward from 2007 to 2015.

Prospective population-based study on the burden of disease from post-streptococcal glomerulonephritis of hospitalised children in New Zealand: epidemiology, clinical features and complications.

AIM: A nationwide 24-month study was conducted (2007-2009), via the New Zealand Paediatric Surveillance Unit to define epidemiology and clinical features of acute poststreptococcal glomerulonephritis (APSGN) in children hospitalised with the illness. METHODS: Paediatricians (n = 215) were requested to report new hospitalised cases fulfilling a case definition of definite (haematuria with low C3 and high streptococcal titres or biopsy proven APSGN) or probable (haematuria with low C3 or high streptococcal titres). RESULTS: A total of 176 cases were identified (definite: n = 138, probable: n = 38) with 63% residing in the Auckland metropolitan region. Sixty-seven percent were in the most deprived quintile. Annual incidence (0-14 years) was 9.7/100,000 (Pacific 45.5, Maori 15.7, European/other 2.6 and Asian 2.1/100,000). Annual incidence was highest in the South Auckland Metropolitan region (31/100,000), Central Auckland 14.9, West/North Auckland metropolitan region 5.9 and for the remainder of New Zealand 5.5/100,000. Age-specific incidence was highest in age 5-9 years (15.1/100,000). Reduced serum complement C3, gross haematuria, hypertension, impairment of renal function and heavy proteinuria were present in 93%, 87%, 72%, 67% and 44% of patients, respectively. Severe hypertension was closely associated with either symptoms of an acute encephalopathy or congestive heart failure. CONCLUSIONS: New Zealand children carry a significant disease burden of hospitalised APSGN with socio-economically deprived; Pacific and Maori children are being over-represented. Significant short-term complications were observed in hospitalised children with APSGN. Persistently very low rates in European/other suggest a preventable disease.