N DE LA MATA1, G MACLEOD2,3, P KELLY1, B ROSALES1, P MASSON4, R MORTON5, K WYBURN3,6, A WEBSTER1,7
1The University Of Sydney, Sydney School Of Public Health, 2University of Notre Dame, School of Medicine, 3The University of Sydney, Sydney Medical School, 4Department of Renal Medicine, Royal Free London NHS Foundation Trust, 5The University of Sydney, NHMRC Clinical Trials Centre, 6Royal Prince Alfred Hospital, Renal Department, 7Westmead Hospital, Centre for Renal and Transplant Research
Aim: To evaluate sex differences in mortality among people receiving kidney replacement therapy in Australia and New Zealand using relative measures of survival to adjust for expected survival.
Background: Chronic kidney disease manifests differently between sexes. Systematic differences in care for kidney failure (KF) may lead to females having comparatively poorer outcomes compared with males, and hence loss of the female survival advantage.
Methods: We included the entire population receiving kidney replacement therapy in Australia, 1980-2013, and New Zealand, 1988-2012, from ANZDATA. Data were linked to national death registers to ascertain deaths. We estimated standardized mortality ratios (SMR), relative survival and years life lost (YLL) using general population data to account for background mortality, adjusting for country, age, sex, and year.
Results: We included 25,042 females (41%) and 35,781 males (59%). While mortality sex differences were minor within the population with KF, once compared with the general population, females with KF had more excess deaths, worse relative survival and greater YLL compared to males with KF. Females had 11.5 times (95%CI:11.3-11.7) and males had 6.7 times (95%CI:6.7-6.8) the expected deaths, with greatest sex disparity among the young and from cardiovascular disease. Relative survival was consistently lower in females with 9% higher excess mortality (95%CI:7-12%). Females had 4-5 YLL more than males across all ages. Kidney transplantation reduced sex differences in excess mortality, with similar relative survival (p=0.42) and smaller difference in YLL.
Conclusions: The impact of KF is more profound for women than men with greater excess mortality, however kidney transplantation reduced these differences. Future research should explore whether systematic differences in access to care exist and possible strategies to mitigate excess mortality among females.
Nicole De La Mata is an early career researcher and biostatistician working with Sydney School of Public Health. Her current research focuses on health outcomes in people with end-stage kidney disease (ESKD), living kidney donors and organ transplant recipients. She has experience in managing and utilizing large observational cohorts and linked health data to evaluate patient outcomes and drive change in health policy. Her interests include cohort studies, data linkage and survival analysis.