There has been a relative paucity of studies on patient safety issues in neurological patients. Neurological conditions that require hospitalization have a number of features that predispose to a variety of potential adverse events. For example, many are associated with neurogenic bladder dysfunction that may be a factor in high rates of catheter-associated urinary tract infections (CAUTI’s). Many of the conditions are associated with reduced mobility, increasing the risk for pressure ulcers and DVT and venous thromboembolism. Some (eg. stroke, Parkinson’s) may be associated with disordered swallowing that predisposes to aspiration and pneumonia. Impairment of balance and/or righting reflexes may lead to falls. Those neurological conditions that impair cognition my also predispose to delirium when other medical insults occur. And several neurological conditions may be associated with obstructive sleep apnea, which may increase the risk of respiratory depression in relation to opioids or other drugs that depress respiration. So we would expect neurological inpatients would have relatively high rates of adverse events while hospitalized.
A new Canadian study provides some perspective on adverse events in this population. Sauro and colleagues (Sauro 2017) did a retrospective cohort study of over 175,000 children and adults admitted to Alberta hospitals from 2009 to 2015 with 1 of 9 neurologic conditions (Alzheimer disease and related dementia, brain tumor, epilepsy, motor neuron disease, multiple sclerosis, parkinsonism/Parkinson disease, spinal cord injury, traumatic brain injury, and stroke).
The mean age of the admitted neurologic patients was 66.5 years and, as you’d expect, multiple comorbid conditions were common. It’s not surprising that age and the presence of comorbidities increased the odds of having an adverse event. The overall proportion of admissions associated with an adverse events among those with a neurologic condition was 11 per 100 admissions and, of those cases with adverse events, 16.1% had more than one. The occurrence of adverse events did vary by diagnosis, being highest for those patients with spinal cord injuries (39.4 per 100 admissions). The most common adverse events were infections and respiratory complications (32.0% and 16.7%, respectively). But for those conditions where surgery was likely (eg. brain tumor, spinal cord injury), surgery-related complications were more common.
As in most studies on adverse events, having an adverse event was associated with increased mortality and increased length of hospital stay. Those experiencing an adverse event had 2.4 times the odds of mortality.
Length of stay was 35.4 days longer for those who had an adverse event compared to those who did not. At first glance, we wondered whether that reported extremely large increase in LOS was a typo because most studies on adverse events in hospitalized patient reveal a more moderate increase in LOS related to adverse events. But we must remember that the relationship between LOS and adverse events is complicated. Not only do adverse events cause longer hospital stays, but the chance of having an adverse event increases with each day of hospitalization.
The most common adverse events in this study were those related to infections and respiratory-related adverse events, anesthesia-related adverse events, CNS-related adverse events, and delirium accounted for a small proportion of adverse events. The authors were somewhat surprised that falls did not rise to a higher level in their ranking of adverse event rates, given that patients with many of the neurological conditions studied are prone to falls. However, the authors explain that this may be related to the difficulties in documenting falls by using ICD-10 codes, which is how they identified most of the adverse events.
We’re also somewhat surprised that adverse drug events were not more frequent in this population. They found only 1.46% of the adverse events related to drugs, a proportion we would have expected to be much higher in a population with this age and comorbidity distribution.
Many of the adverse events seen in neurological inpatients may be preventable. We’ve done numerous columns on CAUTI prevention, swallowing assessment in stroke patients prior to initiating oral feeding, frequent turning of immobile patients, fall prevention strategies, risk assessment for obstructive sleep apnea, delirium prevention strategies, and VTE prophylaxis.
We’re glad to see this study by Sauro and colleagues and hope this stimulates an interest by our neurological colleagues to undertake more patient safety initiatives.
Sauro KM, Quan H, Sikdar KC, et al. Hospital safety among neurologic patients. A population-based cohort study of adverse events. Neurology 2017; 89(3): 284-290