Chapter 12: Patient Safety in the Ambulatory Setting

GENERAL CONCEPTS AND EPIDEMIOLOGY

The point has been well made that while most of the patient safety literature focuses on the inpatient setting, the majority of healthcare encounters occur in the clinic. Consider this: for each inpatient hospitalization, approximately 28 outpatient medical visits take place each year—a ratio that has remained relatively stable over the last 20 years.¹ Indeed, ambulatory visits now account for over one-third of all healthcare spending in the United States.² Nevertheless, early emphasis on patient safety in the hospital was a natural first step. Inpatients are sicker, making the stakes higher. Hospital errors are often more visible. Additionally, when compared to most community-based physician practices, hospitals have greater resources to research and address safety challenges.

The landscape is shifting. With the passage of the Affordable Care Act, millions of Americans previously uninsured are now covered and able to access outpatient care more easily. According to the Agency for Healthcare Research and Quality, 30% of previously uninsured adults under 65 became insured between 2013 and 2014.³ Moreover, new payment models – including readmission penalties, bundled payments, and Accountable Care Organizations—place greater emphasis on maintaining the health of patients across the continuum, and patient safety is an important component of population health. All of these factors are prompting increased focus on ambulatory safety, and healthcare delivery organizations and researchers (and research funders) are responding accordingly.

While some of the key principles of safety are the same regardless of setting, ambulatory safety does present some new challenges and opportunities. The scope of potential errors may be larger in the hospital. For example, major hospital safety targets, including healthcare-associated infections, pressure ulcers, and blood clots, are less relevant in the clinic. But both settings are plagued by medication and laboratory errors as well as transitions of care and communication problems. And although the ambulatory setting has historically seen fewer surgical errors, the rapid growth in outpatient surgery makes this an increasingly significant problem.

Recent research has helped to better characterize the frequency and types of safety issues associated with outpatient medicine, as well as potential solutions for them. One study estimated that approximately 75,000 hospitalizations per year in the United States are due to preventable adverse events that occur in the ambulatory setting.⁴ In the clinic, adverse drug events and diagnostic errors are particularly common, with some estimates suggesting that about 5% of all U.S. adults experience a diagnostic error in outpatient medicine every year.^5–7 Prescribing errors occur at a particularly high rate: one study found that nearly one in four prescriptions contained at least one mistake involving dosing, patient instructions, or legibility.⁸ Adverse events occurring soon after hospital discharge are especially common,^9,10 and may result from communication breakdown between inpatient and outpatient providers,¹¹ pending test results at the time of hospital discharge,¹² incorrect medication reconciliation,¹³ and increased stress ...