Ethnic differences in the natural progression of nephropathy among diabetes patients in New Zealand: hospital admission rate for renal complications, and incidence of end-stage renal disease and renal death

Abstract

Aims/hypothesis: We estimated the incidence of chronic renal failure, the incidence of end-stage renal disease (ESRD) and renal mortality rates among New Zealand European and Maori patients with diabetes and estimated the ethnic difference in the risk of developing renal failure.

Methods: A renal complication-free cohort of adult diabetes patients registered with Waikato regional diabetes service, diagnosed with diabetes before 2003, were retrospectively followed for 4 years. Events of interest were renal hospital admission, ESRD and death coded with renal disease. Incidences of renal hospital admission, ESRD and death from renal disease were calculated for NZ Europeans and Maori patients with diabetes. Ethnic and sex differences in the risks of these renal outcomes were estimated using a Cox proportional hazards model.

Results: Of the 7,900 patients followed up, 116 (1.5%) had a renal admission, 42 (0.5%) started dialysis/transplantation and 21 (0.27%) died from renal disease. Maori diabetes patients had significantly higher incidences of dialysis or transplantation and rates of renal admission and renal death. Adjusted hazard ratios indicate that, compared with NZ Europeans with diabetes, Maori diabetes patients had a significantly higher risk of ESRD, renal admission and renal death (46-fold, seven-fold and four-fold increases, respectively). Maori patients progressed at a significantly faster rate from first hospital admission for chronic renal disease to ESRD.

Conclusions/interpretation: There were huge ethnic disparities in outcomes from renal disease. Screening for early kidney disease among Maori diabetes patients, intensive management of risk factors and further research on the aetiology of renal disease among Maoris is recommended.