Effect of angiotensin converting enzyme inhibitors and angiotensin receptor blockers on serum potassium levels and renal function in ambulatory outpatients: risk factors analysis.

BACKGROUND: Angiotensin II inhibition with angiotensin converting enzyme inhibitors (ACEinh) and angiotensin receptor blockers (ARB) has reno- and cardioprotective effects but can also cause acute renal insufficiency and/or hyperkalemia.

STUDY DESIGN: A retrospective analysis was performed in an ambulatory population, to define the incidence and risk factors for hyperkalemia in ACEinh/ARB naïve patients.

SETTING AND PARTICIPANTS: Records of patients from 10 Oklahoma regional VA outpatient facilities, in whom ACEinh/ARB was initiated from January 2000 to May 2004, were reviewed. Diabetes mellitus, estimated glomerular filtration rate (eGFR), in mL/min/1.73 m, according to the KDOQI guidelines for chronic kidney disease (CKD), and concurrent medications were recorded.

RESULTS: ACEinh/ARB were well tolerated in unselected consecutive ACEinh/ARB naïve patients with baseline serum potassium (sK) < or = 5.0 mEq/L in a general ambulatory population with 2.5% (23) of 931 developing hyperkalemia (sK > or = 5.5 mEq/L). sK > or = 6 mEq/L was seen in <1% (7) of patients. The incidence of hyperkalemia was 1.2% in CKD stage 1(1/86), 1.1% in CKD stage 2 (5/469), 3.1% in CKD stage 3 (10/318), and 13.7% in CKD stage 4 (7/51). ACEinh/ARB naïve patients with baseline sK >5.0 mEq/L also tolerated ACEinh/ARB with 7.5% (3/40) developing sK >6.0 mEq/L. Diabetes mellitus did not affect the incidence of hyperkalemia independent of GFR.

CONCLUSIONS: Although generally safe, ACEinh/ARB poses a small risk for hyperkalemia in patients with reduced GFR. Because the propensity is incremental with declining GFR, these agents should be used with caution in advancing stages of CKD. Presence of diabetes does not affect the development of hyperkalemia.