Chronic kidney disease is associated with increased risk of sudden cardiac death among patients with coronary artery disease

Abstract

Sudden cardiac death is the most common cause of mortality among patients with end-stage kidney disease maintained on hemodialysis. To examine whether this increased risk is also seen with less advanced kidney disease, we studied the relationship between glomerular filtration rate and risk of sudden cardiac death in patients with moderate kidney disease and known coronary artery disease. This retrospective longitudinal study encompassed 19,440 consecutive patients who underwent cardiac catheterization at a single academic institution. There were 522 adjudicated sudden cardiac death events, yielding an overall rate of 4.6 events per 1000 patient years. This figure reflected rates of 3.8 events in 14,652 patients with estimated glomerular filtration rates (eGFR) > or =60 (stage 2 CKD or better) and 7.9 events in 4788 patients with glomerular filtration rates <60 (stage 3-5 CKD), all normalized to 1000 patient-years. After adjusting for differences in known cardiac risk factors and other covariates in a multivariate Cox proportional hazards model, the eGFR was independently associated with sudden cardiac death (hazard ratio (HR)=1.11 per 10 ml/min decline in the eGFR). Our analysis found that reductions in the eGFR in CKD stages 3-5 are associated with a progressive increase in risk of sudden cardiac death in patients with coronary artery disease. Additional studies are needed to better characterize the mechanisms by which reduced kidney function increases this risk.

Figure 1. Study flow diagram illustrating cohort entry criteria and exclusions

A total of 19,440 patients were included from among all patients undergoing cardiac catheterization over the 12-year study period after the exclusions listed above.

Figure 2. Rates of SCD by the baseline eGFR category

Rates shown as events per 1000 patient-years and were as follows: eGFR ≥60 ml/min, 3.8 (95% CI: 0, 8); eGFR 15–59 ml/min, 7.3 (95% CI: 2, 13); eGFR < 15 not on dialysis, 12.5 (95% CI: 5, 20); and dialysis, 24.1 (95% CI: 14, 34). For all subsequent analyses, dialysis and non-dialysis patients with eGFR <15 were combined into a single group (eGFR <15).

Figure 3. Unadjusted SCD risk expressed as logarithm of the hazard ratio across the spectrum of eGFR

Red lines illustrate 95% confidence intervals. eGFR is inversely and linearly related to increased SCD risk. There does not appear to be an increasing benefit for SCD-free survival above GFR values over 90 ml/min/ 1.73m².