High serum potassium levels after using losartan can reflect more severe renal disease

Excerpt

To the Editor: We read with great interest the paper by Miao et al. [1] showing in a post hoc analysis of the Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL) study [2] that increased serum potassium levels affect renal outcomes. The authors’ observations are intriguing as they show that not all the patients in the study benefited from using inhibitors of the renin–angiotensin system (RAS); in fact, some may have suffered adverse events, including an acceleration of renal disease progression, most notably in those with hyperkalaemia. Miao and colleagues argue that the changes in potassium levels are dependent on losartan therapy, but its effect on risk for renal events is independent of the use of losartan (Table 3 in Miao et al. [1]). This is intriguing, as the percentage of patients on potassium-sparing diuretics is quite small and most of the other anti-hypertensive medications are not commonly associated with hyperkalaemia. …