Antihypertensive Medications and the Prevalence of Hyperkalemia in a Large Health System

Little is known about the frequency and patterns of hyperkalemia in clinical settings. We evaluated the association between baseline antihypertensive medications that may affect potassium levels (angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, β-blockers, loop/thiazide diuretics, and potassium-sparing diuretics) and hyperkalemia, defined by potassium >5 mEq/L and >5.5 mEq/L, over a 3-year time period in 194 456 outpatients in the Geisinger Health System, as well as actions taken after an episode of hyperkalemia. The proportions of patients with 0, <2, 2 to 4, and ≥4 potassium measurements per year were 20%, 58%, 16%, and 6%. Potassium levels >5 mEq/L and >5.5 mEq/L occurred in 10.8% and 2.3% of all patients over the 3-year period; among patients with ≥4 measurements per year, corresponding values were 39.4% and 14.6%. Most cases of hyperkalemia occurred only once during follow-up. The antihypertensive medication class most strongly associated with hyperkalemia was angiotensin-converting enzyme inhibitors. Among patients with a measurement of potassium >5.5 mEq/L, only 24% were seen by a nephrologist and 5.2% were seen by a dietician during the 3-year period. Short-term actions after a potassium measurement >5.5 mEq/L included emergency room visit (3.1% within 7 days), remeasurement of potassium (44.3% with 14 days), and change in a potassium-altering medication (26.4% within 60 days). The most common medication changes were discontinuation/dose reduction of an angiotensin-converting enzyme inhibitor/angiotensin receptor blocker or potassium-sparing diuretic, which occurred in 29.1% and 49.6% of people taking these medications, respectively. In conclusion, hyperkalemia is common. Future research may enable optimal renin-angiotensin-aldosterone system inhibitor use with improved management of hyperkalemia.

GFR decline and mortality risk among patients with chronic kidney disease

BACKGROUND AND OBJECTIVES

Estimates of the effect of estimated GFR (eGFR) decline on mortality have focused on populations with normal kidney function, or have included limited information on factors previously shown to influence the risk of death among patients with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We retrospectively assessed the effect of rate of eGFR decline on survival of patients with CKD receiving primary care through a large integrated health care system in central Pennsylvania between January 1, 2004, and December 31, 2009.

RESULTS

A total of 15,465 patients were followed for a median of 3.4 years. Median rates of eGFR change by those in the lower, middle, and upper tertiles of eGFR slope were -4.8, -0.6, and 3.5 ml/min per 1.73 m(2)/yr, respectively. In Cox proportional hazard modeling for time to death, adjusted for baseline proteinuria, changes in nutritional parameters, and episodes of acute kidney injury during follow-up (among other covariates), the hazard ratio for those in the lower (declining) and upper (increasing) eGFR tertiles (relative to the middle, or stable, tertile) was 1.84 and 1.42, respectively. Longitudinal changes in nutritional status as well as episodes of acute kidney injury attenuated the risk only modestly. These findings were consistent across subgroups.

CONCLUSIONS

eGFR change over time adds prognostic information to traditional mortality risk predictors among patients with CKD. The utility of incorporating eGFR trends into patient-risk assessment should be further investigated.