Saturday, June 26, 2010
Reverse epidemiology in ESRD: Digoxin
Conventional risk factors of cardiovascular disease and mortality in the general population such as obesity, hypercholesterolemia, and hypertension appear to be paradoxically protective and are associated with increased survival among dialysis patients (Kalantar-Zadeh et al, Kidney Int. 2003). Also, it was reported recently that there is paradoxical increase in the risk of stroke among dialysis patients receiving warfarin therapy for atrial fibrillation (Chan et al, JASN Oct 2009). Now there is an addition to the list of reverse epidemiology in ESRD. In the current issue of JASN, Chan and colleagues report increased mortality with digoxin use in ESRD patients (Chan et al, JASN, June 2010). In this study, authors compared 4549 dialysis patients on digoxin with 116,315 dialysis patients who were not on digoxin. This is a retrospective study. However, authors did propensity score analysis to match patients with similar comorbidities in both groups. It was found that digoxin use was associated with 28% increased risk of death. This was most pronounced in patients with lower predialysis serum potassium of less than 4.3 mEq/L. It is likely that hypokalemia, which frequently occurs immediately post dialysis in our ESRD patients, enhances the toxicity of digoxin. In conclusion, we all apply same principles of medicine learnt from general population to our dialysis patients. It seems we have to re-examine everything in our ESRD population.