Abstract & Commentary

Risks of ICU Admission Include Unintentional Discontinuation of Medications

By Leslie A. Hoffman, RN, PhD, Department of Acute/Tertiary Care, School of Nursing, University of Pittsburgh, is Associate Editor for Critical Care Alert.

Synopsis: Admission to an ICU increased risk for unintentional medication discontinuation in four of five medication groups commonly used to manage a chronic illness.

Source: Bell CM, et al. Association of ICU or hospital admission with unintentional discontinuation of medications for chronic diseases. JAMA 2011;306:840-847.

To determine the risk of potentially unintended discontinuation of common, evidence-based medications for chronic disease, Bell and colleagues examined administrative records for 12 years (1997–2009) for all hospitalized patients and all outpatient prescriptions in Ontario, Canada. Patients were included if they were ≥ 66 years of age and continuously prescribed one of five medications for at least 12 months: 1) statins, 2) antiplatelet/anticoagulants, 3) levothyroxine, 4) an inhaled respiratory drug (anticholinergic, beta-agonist, steroid), or 5) a gastric acid-suppressing drug. Three cohorts were formed: 1) patients discharged after an admission that included an ICU stay (n = 16,474), 2) patients discharged after an admission that did not include an ICU admission (n = 171,438), and 3) patients not hospitalized (controls; n = 208,468). The study controlled for a number of potential confounding variables, including age, sex, income, length of stay, and disease burden (number of medications prescribed). Separate analyses were performed for each of the five medication groups.

Patients admitted to a hospital were more likely to experience a potentially unintentional discontinuation of a medication compared to controls across all medication groups examined. The adjusted odds ratio (AOR) ranged from 1.18 (95% confidence interval [CI], 1.14-1.23) for discontinuing levothyroxine in 12.3% of hospitalized patients vs 11.0% of controls to an AOR of 1.86 (95% CI, 1.77-1.97) for discontinuing antiplatelet/anticoagulant agents in 19.4% of hospitalized patients vs 11.8% of controls. With ICU exposure, the AOR ranged from 1.48 (95% CI, 1.39-1.57) for discontinuing statins in 14.6% of ICU patients to an AOR of 2.31 (95% CI, 2.07-2.57) for discontinuing antiplatelet/anticoagulant agents in 22.8% of ICU patients vs the control group. Admission to an ICU was associated with an additional risk of medication discontinuation in four of five medication groups compared to hospitalizations without an ICU admission. A 1-year follow-up of patients with discontinued medications showed an elevated AOR for the secondary composite outcome of death, emergency department visit, or emergent hospitalization of 1.07 (95% CI, 1.03-1.11) for statins and of 1.10 (95% CI, 1.03-1.16) in the antiplatelet/anticoagulant agents group.


This study highlights a serious risk factor common to all care transitions. When patients change care providers, critical information may be omitted or not clearly communicated, resulting in an increased risk for adverse events. In this study, hospitalized patients experienced an increased risk for unintentional discontinuation of a medication at discharge. Admission to an ICU was associated with a higher risk for this outcome. At 1 year, there was an increased risk of death, an emergency department visit, or emergent hospitalization when two groups of medications — statins and antiplatelet/anticoagulant agents — were not continued after hospitalization.

Given the retrospective design, it is possible that decisions to discontinue medications may have been intentional. However, the authors took multiple steps to minimize this potential. All of the selected medications had well-established long-term efficacy for the management of a chronic disease. Only patients who had taken the medication continuously for 1 year were included. Unintentional discontinuation was defined as no renewal within 90 days plus a grace period to allow for medications remaining from past prescriptions. New prescriptions within the same drug classification were not categorized as a discontinuation. Given these constraints, the percentage of patients who experienced unintentional medication discontinuation is very alarming. For hospitalized patients, antiplatelets/anticoagulants (19.1%) led, followed by statins (13.5%), gastric acid suppressors (12.7%), levothyroxine (12.1%), and respiratory inhalers (4.4%). For ICU patients, the sequence was the same but the percentage was higher, e.g., antiplatelets/anticoagulants (22.8%), followed by statins (14.6), gastric acid suppressors (15.4%), levothyroxine (15%), and respiratory inhalers (5.4%). The authors posed several explanations for a higher risk in ICU patients. ICU patients likely experience more transitions. Care is focused on the critical episode, not an underlying chronic illness. Some medications get discontinued and this increases the risk that they will be forgotten at ICU discharge.

Given these findings, what can be done to improve patient safety? Enhanced awareness of the potential for unintentional discontinuation on the part of all providers is one option. However, the hectic nature of critical care makes it doubtful that omissions will not occur, despite good intentions. The best solution is likely electronic medical records that list prior medications and, therefore, make it easier to recall what needs to be continued or reordered during each care transition.