Use of Renally Inappropriate Medications in Older Veterans: A National Study.
OBJECTIVE
To determine how many ambulatory older adults with chronic kidney disease receive medications that are contraindicated or dosed excessively given their level of renal function.


METHODS
Cross-sectional retrospective study.


METHODS
U.S. Department of Veterans Affairs (VA) clinics.


METHODS
Individuals aged 65 and older with a creatinine clearance (CrCl) of 15 to 49 mL/min (N = 83,850; mean age 80; 96% male).


METHODS
Forty medications that require dose adjustment or are contraindicated in people with impaired renal function were examined. Medication use and CrCl (calculated using the Cockroft-Gault equation) were assessed using VA pharmacy, laboratory, and other data sources as of October 2007.


RESULTS
Thirteen percent of older veterans with a CrCl of 30 to 49 mL/min and 32% of those with a CrCl of 15 to 29 mL/min received one or more drugs that were contraindicated or prescribed at an excessive dose given the individual's level of renal function. The strongest risk factor for renally inappropriate prescribing was number of medications used; the risk of receiving renally inappropriate medications was 5.5 times as high (95% confidence interval = 5.1-5.9) in older adults taking 10 or more medications as in those taking one to three medications. Ranitidine, allopurinol, and metformin together accounted for 76% of renally misprescribed medications in individuals with a CrCl of 30 to 49 mL/min. Glyburide, ranitidine, gemfibrozil, carvedilol, and allopurinol accounted for 47% of renally misprescribed drugs for individuals with a CrCl of 15 to 29 mL/min.


CONCLUSIONS
Inappropriate prescribing of renally cleared medications is common in ambulatory older veterans, with only a few medications accounting for most of these prescribing problems.
School of Medicine, University of California at Davis, Davis, California.|Division of Geriatrics, University of California San Francisco, San Francisco, California.|San Francisco Veterans Affairs Medical Center, San Francisco, California.
Flora
F
Chang
Division of Nephrology, University of Washington, Seattle, Washington.|Seattle Veterans Affairs Medical Center, Seattle, Washington.
Ann M
AM
O'Hare
Division of Geriatrics, University of California San Francisco, San Francisco, California.|San Francisco Veterans Affairs Medical Center, San Francisco, California.
Yinghui
Y
Miao
Division of Geriatrics, University of California San Francisco, San Francisco, California.|San Francisco Veterans Affairs Medical Center, San Francisco, California.
Michael A
MA
Steinman
D000368:Aged; D000369:Aged, 80 and over; D000493:Allopurinol / Q000008:administration & dosage; D000619:Aminohydrolases; D001835:Body Weight; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D057970:Inappropriate Prescribing / Q000706:statistics & numerical data*; D008297:Male; D008687:Metformin / Q000008:administration & dosage; D011899:Ranitidine / Q000008:administration & dosage; D051436:Renal Insufficiency, Chronic / Q000188:drug therapy*; D012189:Retrospective Studies; D014481:United States; D014728:Veterans
D000493:Allopurinol; D011899:Ranitidine; D008687:Metformin; D000619:Aminohydrolases; C023157:creatinine deiminase
chronic kidney disease; drug use; pharmacoepidemiology; quality of care; veterans