The Epidemiology of Serious Skin Infections in New Zealand Children: Comparing the Tairawhiti Region with National Trends

Aim: Serious skin infections are an increasing problem for New Zealand children with the highest national incidence in the Gisborne (Tairawhiti) region on the East Coast of New Zealand's North Island. This study aimed to describe the epidemiology of serious skin infections in children in this region, and make comparisons with equivalent national data to identify factors that might be contributing to elevated infection rates.

Methods: Hospitalisation data were reviewed for 0-14 year old children in the Tairawhiti region discharged from hospital with a serious skin infection between 1990 and 2007. A range of demographic variables were compared to equivalent data for New Zealand cases over the same period. The ratio of observed to expected discharges was calculated after indirectly standardising the Tairawhiti population age, ethnicity and deprivation composition to that of the total New Zealand population.

Results: In Tairawhiti the age-adjusted incidence of serious skin infections increased from 641.1/100,000 in 1990-1999 to 988.4/100,000 in 2000-2007, while the New Zealand incidence increased from 354.3/100,000 to 531.7/100,000. Preschool-aged children, Māori children, and those living in deprived neighbourhoods had the highest infection rates in all regions. The disparity between Māori and non-Māori children was significantly greater in Tairawhiti than nationally. The standardised ratio of observed to expected discharges in Tairawhiti compared with New Zealand was 1.42 (95%CI 1.32-1.52) in 1990-1999 and 1.28 (95%CI 1.19-1.36) in 2000-2007.

Conclusions: Serious skin infections are an increasing problem for all New Zealand children, but incidence rates in the Tairawhiti region are consistently greater than average national trends, with significantly larger ethnic disparities. The population composition of this region only partly accounts for the difference, suggesting the involvement of other unknown aetiological factors; these warrant further research.