L SUKKAR1,2, B SMYTH1,2, A KANG1, M JUN1, C FOOTE3, K ROGERS1, A SCARIA1, B NEUEN1, M GALLAGHER1, A CASS4, D SULLIVAN5, C POLLOCK6, G Wong7, J Knight1, D Peiris1, M Jardine1
1The George Institute For Global Health, , Australia, 2Sydney School of Public Health, The University of Sydney, , Australia, 3Concord Repatriation General Hospital, , Australia, 4Menzies School of Health Research, , Australia, 5NHMRC Clinical Trials Centre, The University of Sydney, , Australia, 6Kolling Institute for Medical Research, , Australia, 7Centre for Kidney Research, The University of Sydney , , Australia
Aim: To examine the relative contributions of myocardial and endoluminal disease to cardiovascular morbidity as kidney function declines.
Background: The pathophysiological process behind cardiovascular morbidity differs between people with Chronic Kidney Disease and the general population.
Methods: Based on data from the EXTEND45 study (the 45 and Up Study linked to hospital and community pathology datasets by the Centre for Health Record and Linkage[CHeReL]), we identified a population-based cohort (2006-2014) of 41,099 people aged ≥45 years who had a measure of kidney function(estimated glomerular filtration rate[eGFR]). Cardiac hospitalisations were identified using ICD-10 codes and classified into endoluminal (all coronary artery disease including complications), myocardial (all cardiac failure and arrhythmias) or other (all valvular disease and infective cardiac processes). We compared the proportion of endoluminal, myocardial and other causes of hospitalisation by KDIGO stage using the Chi-squared test and the trend in proportions between endoluminal and myocardial causes using the Cochran-Armitage trend test.
Results: Of 41,099 participants 3,177 experienced ≥1 hospitalised cardiac event(1901, 837, 439 endoluminal, myocardial and other respectively) over a median follow-up of 1.9 years. Endoluminal causes as a total proportion of cardiac hospitalisation decreased as kidney function declined(64.5%, 61.8%, 57.2%, 53.1%, 50% for Stages 1, 2, 3a, 3b, and 4-5, respectively) while myocardial(26.7%, 25.5%, 27.0%, 28.1%, 29.6% respectively) causes increased(P-value 0.0005) and this trend was significant(P= 0.02). Other causes were also found to increase(8.8%, 12.7%, 15.9%, 18.8%, 20.5% respectively, P-value 0.0005).
Conclusions: The trend towards a decrease in the proportion of endoluminal and an increase in myocardial causes of hospitalisation with kidney function decline was significant. Understanding risk factors that lead to this divergence in cardiovascular morbidity may help reduce the burden.
Dr Louisa Sukkar is a PhD scholar at the George Institute for Global health and a clinical nephrologist. Her research interests is in understanding the progression of chronic kidney disease, its associated co-morbidities and its impact on patients. Her research explores the determinants of progression with a particular focus on processes of care of chronic disease and its relationship to health outcomes and health resource utilization.