2019 HSR&D/QUERI National Conference

4025 — Holding Nephrotoxic Medications at Admission and Risk for Hospital-Acquired Acute Kidney Injury in General Medicine Inpatients

Lead/Presenter: Katharyn Smith,  COIN - Iowa City
All Authors: Smith KL (Department of Pharmacy Services, Iowa City VA Healthcare System), Heintz SJ (Department of Pharmacy Services, Iowa City VA Healthcare System), Jacobson MM (Department of Pharmacy Services, Iowa City VA Healthcare System) Mosher HJ (Center for Access & Delivery Research and Evaluation , Iowa City VA Healthcare System) Swee ML (Center for Access & Delivery Research and Evaluation , Iowa City VA Healthcare System) Egge J (Department of Pharmacy Services, Iowa City VA Healthcare System) Lund BC (Center for Access & Delivery Research and Evaluation, Iowa City VA Healthcare System)

Objectives:
Nephrotoxic medication exposure is a major risk factor for hospital-acquired acute kidney injury (HA-AKI). Current literature examining benefits of holding nephrotoxic medications is limited to patients undergoing specific cardiac surgeries or contrast-based diagnostic procedures. The purpose of this study was to determine whether holding nephrotoxic medications at time of admission in a general medicine population is associated with reduced risk for HA-AKI.

Methods:
This retrospective cohort study included 800,918 Veterans Health Administration medical admissions from July 1, 2010 through June 30, 2016. Nephrotoxic medications examined were: angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), diuretics, and nonsteroidal anti-inflammatory drugs (NSAIDs). Four non-nephrotoxic medications (metoprolol, amlodipine, simvastatin, atorvastatin) were included as controls. The primary outcome was development of HA-AKI within 7 days following admission. Multivariable logistic regression was used to examine factors associated with HA-AKI, including adjustment for known confounders.

Results:
HA-AKI risk was significantly lower when holding versus continuing the following nephrotoxic medications (OR, 95% CI): ACE inhibitors (0.83, 0.79-0.87), ARBs (0.87, 0.80-0.95), loop diuretics (0.56, 0.53-0.59), thiazide diuretics (0.64, 0.59-0.68), and potassium-sparing diuretics (0.91, 0.84-0.99). A similar effect size was observed for NSAIDs but did not reach statistical significance (OR = 0.92, 95% CI: 0.84-1.01). HA-AKI risk did not differ between held versus continued status for any of the control medications.

Implications:
Holding nephrotoxic medications in general medicine inpatients was associated with decreased risk for HA-AKI.

Impacts:
Holding nephrotoxic medications on admission could substantially reduce risk for HA-AKI among general medicine inpatients across VHA. Our findings support the need for prospective, controlled trials to confirm these findings, before widespread implementation in clinical practice could be recommended.