The frequency of hyperkalemia and its significance in chronic kidney disease.
BACKGROUND
Hyperkalemia is a potential threat to patient safety in chronic kidney disease (CKD). This study determined the incidence of hyperkalemia in CKD and whether it is associated with excess mortality.


METHODS
This retrospective analysis of a national cohort comprised 2 103 422 records from 245 808 veterans with at least 1 hospitalization and at least 1 inpatient or outpatient serum potassium record during the fiscal year 2005. Chronic kidney disease and treatment with angiotensin-converting enzyme inhibitors and/or angiotensin II receptor blockers (blockers of the renin-angiotensin-aldosterone system [RAAS]) were the key predictors of hyperkalemia. Death within 1 day of a hyperkalemic event was the principal outcome.


RESULTS
Of the 66 259 hyperkalemic events (3.2% of records), more occurred as inpatient events (n = 34 937 [52.7%]) than as outpatient events (n = 31 322 [47.3%]). The adjusted rate of hyperkalemia was higher in patients with CKD than in those without CKD among individuals treated with RAAS blockers (7.67 vs 2.30 per 100 patient-months; P < .001) and those without RAAS blocker treatment (8.22 vs 1.77 per 100 patient-months; P < .001). The adjusted odds ratio (OR) of death with a moderate (potassium, >or=5.5 and <6.0 mEq/L [to convert to mmol/L, multiply by 1.0]) and severe (potassium, >or=6.0 mEq/L) hyperkalemic event was highest with no CKD (OR, 10.32 and 31.64, respectively) vs stage 3 (OR, 5.35 and 19.52, respectively), stage 4 (OR, 5.73 and 11.56, respectively), or stage 5 (OR, 2.31 and 8.02, respectively) CKD, with all P < .001 vs normokalemia and no CKD.


CONCLUSIONS
The risk of hyperkalemia is increased with CKD, and its occurrence increases the odds of mortality within 1 day of the event. These findings underscore the importance of this metabolic disturbance as a threat to patient safety in CKD.
Einhorn
Lisa M
LM
Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
Zhan
Min
M
Hsu
Van Doren
VD
Walker
Lori D
LD
Moen
Maureen F
MF
Seliger
Stephen L
SL
Weir
Matthew R
MR
Fink
Jeffrey C
JC
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006947:Hyperkalemia / Q000097:blood / Q000453:epidemiology* / Q000209:etiology; D015994:Incidence; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000097:blood*; D011379:Prognosis; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology; D014728:Veterans / Q000706:statistics & numerical data; D055815:Young Adult
D011188:Potassium