Cause of death in patients with end-stage renal disease: assessing concordance of death certificates with registry reports

Objectives: To assess concordance in reporting, in two Australian national datasets, of cause of death of patients with end-stage renal disease (ESRD). Methods: For deaths in 1997-99, we compared 'cause of death' and 'primary renal disease', as coded in the Australian and New Zealand Dialysis and Transplant Registry (ANZDATA), with 'underlying' and 'associated' causes of death (based on death certificates), as coded by the Australian Bureau of Statistics (ABS). Dates of birth and death and sex identified the same individuals in the two datasets. Deaths from the three States for which date of birth was not available from death certificates were excluded. Cause of death was compared at the ICD-10 chapter level. Results: Of 1,728 ANZDATA patients from NSW, SA, WA, NT and ACT who died during 1997-99, 1,117 (65%) could be matched to a record in the ABS dataset for the corresponding jurisdictions. The death certificates of 219 (20%) of these 1,117 patients made no mention of chronic renal failure. Overall, agreement on cause of death was poor (kappa=0.22). Using ANZDATA information on cause of death and ABS underlying cause of death, only 38% of patients had the same cause (at the ICD-10 chapter level) recorded in both datasets. Additional information on primary renal disease (ANZDATA) and up to 12 associated causes of death (ABS) was required to obtain substantial agreement. Conclusion and implications: Death certificates and ANZDATA records provide differing causes of death for ESRD patients. Information from these sources was not directly comparable. Neither dataset provided a complete picture of renal disease as a cause of death in Australia.