Mortality and hospitalisation costs of rheumatic fever and rheumatic heart disease in New Zealand

Abstract

Aims: To estimate the annual mortality and the cost of hospital admissions for acute rheumatic fever (ARF) and rheumatic heart disease (RHD) for New Zealand residents.

Methods: Hospital admissions in 2000-2009 with a principal diagnosis of ARF or RHD (ICD9_AM 390-398; ICD10-AM I00-I099) and deaths in 2000-2007 with RHD as the underlying cause were obtained from routine statistics. The cost of each admission was estimated by multiplying its diagnosis-related group (DRG) cost weight by the national price for financial year 2009/2010.

Results: There were on average 159 RHD deaths each year with a mean annual mortality rate of 4.4 per 100, 000 (95% confidence limit 4.2, 4.7). Age-adjusted mortality was five- to 10-fold higher for Māori and Pacific peoples than for non-Māori/Pacific. The mean age at RHD death (male/female) was 56.4/58.4 for Māori, 50.9/59.8 for Pacific and 78.2/80.6 for non-Māori, non-Pacific men and women. The average annual DRG-based cost of hospital admissions in 2000-2009 for ARF and RHD across all age groups was $12.0 million (95% confidence limit $11.1 million, $12.8 million). Heart valve surgery accounted for 28% of admissions and 71% of the cost. For children 5-14 years of age, valve surgery accounted for 7% of admissions and 27% of the cost. Two-thirds of the cost occurs after the age of 30.

Conclusions: ARF and RHD comprise a burden of mortality and hospital cost concentrated largely in middle age. Māori and Pacific RHD mortality rates are substantially higher than those of non-Māori/Pacific.