Laboratory monitoring of potassium and creatinine in ambulatory patients receiving angiotensin converting enzyme inhibitors and angiotensin receptor blockers.
OBJECTIVE
Serum potassium and creatinine monitoring is recommended for patients prescribed angiotensin converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB). Much has been written about hyperkalemia associated with these drugs; little is known about laboratory monitoring patterns. The purpose of this retrospective cohort study was to assess creatinine and potassium monitoring and characteristics associated with monitoring among patients dispensed ACEi or ARB.


METHODS
This study was conducted in 10 United States health maintenance organizations. Study patients (n = 52 906) were aged 18 or older with dispensings of ACEi or ARB for at least 1 year. Serum potassium and creatinine monitoring were assessed from administrative data and medical records.


RESULTS
More than two-thirds (68.4%) of patients received laboratory monitoring. Likelihood of monitoring increased with age (adjusted odds ratio [OR] 2.10; 95% confidence interval [95%CI] 1.93, 2.28 [individuals >or= 80 compared to <50 years]), >9 outpatient visits (OR 1.46; 95%CI 1.39, 1.54), hospitalization (OR 1.15; 95%CI 1.06, 1.25), concomitant medications (potassium [OR 2.01; 95%CI 1.84, 2.20], diuretics [OR 1.54; 95%CI 1.47, 1.61], digoxin [OR 1.15; 95%CI 1.01, 1.30]), and comorbidities (diabetes [OR 1.68; 95%CI 1.61, 1.75], heart failure [OR 1.73; 95%CI 1.57, 1.90], chronic kidney disease [OR 2.95; 95%CI 2.48. 3.51]).


CONCLUSIONS
Nearly one-third of patients dispensed ACEi or ARB did not undergo laboratory monitoring at least yearly. Though patients at increased risk of hyperkalemia were more likely to be monitored, many remained unmonitored.
Raebel
Marsha A
MA
Kaiser Permanente of Colorado Clinical Research Unit and School of Pharmacy, University of Colorado at Denver and Health Sciences Center, Denver, CO 80237-8066, USA. Marsha.A.Raebel@kp.org
McClure
David L
DL
Simon
Steven R
SR
Chan
K Arnold
KA
Feldstein
Adrianne
A
Andrade
Susan E
SE
Lafata
Jennifer Elston
JE
Roblin
Douglas
D
Davis
Robert L
RL
Gunter
Margaret J
MJ
Platt
Richard
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D047228:Angiotensin II Type 1 Receptor Blockers / Q000009:adverse effects / Q000627:therapeutic use*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood*; D016903:Drug Monitoring / Q000379:methods / Q000706:statistics & numerical data; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D006947:Hyperkalemia / Q000097:blood / Q000139:chemically induced; D008297:Male; D008875:Middle Aged; D010045:Outpatients / Q000706:statistics & numerical data*; D011188:Potassium / Q000097:blood*; D011237:Predictive Value of Tests; D012189:Retrospective Studies
D047228:Angiotensin II Type 1 Receptor Blockers; D000806:Angiotensin-Converting Enzyme Inhibitors; D003404:Creatinine; D011188:Potassium