Glossary of key terms

Here we sort out some of the key concepts, history and background in patient safety issues.

Adverse Event

Any medical intervention such as a test, treatment, hospitalization or surgery can result in an undesirable outcome that is not caused by the underlying disease. Adverse events are common and have a wide range of severity, including death. They may be preventable or not preventable.

The term “adverse event” debuted in 1991 with the Harvard Medical Practice Study, which tried to measure the extent of malpractice in New York state hospitals. It defined an adverse event as “an unintended injury that was caused by medical management and that resulted in measurable disability.”

The HHS Office of the Inspector General, which studies harms from medical care, defines an adverse event as “an incident that prolonged a patient’s stay, caused permanent harm, required life-saving intervention or contributed to death.” That agency distinguishes an adverse event from a “temporary harm event,” which is harm from a medical intervention that did not prolong a patient’s hospital stay, require life-sustaining intervention, or cause lasting harm.

The vast majority of adverse events go undetected, which has led to the development of technology that can detect “triggers,” or clues that harm has occurred. Researchers are also working on systems to identify conditions under which adverse events occur in order to prevent them.

Alert fatigue (also called alarm fatigue)

Because of poor design of electronic health records and medical systems, doctors, nurses and other clinicians routinely have to override warnings and alarms that have little relevance for patient care. While intended to make patients safer in theory, the proliferation of alerts may increase the chance patients will be harmed when an important warning is missed.

​​The average clinician sees “a staggering number of alerts” each day at work, making it too easy over time to spot the critical alarm from among the inconsequential ones, according to a primer by the Agency for Healthcare Resources and Quality (AHRQ). The consequences of this barrage of alerts is a “desensitization” that clinicians develop in order to cope, wrote Aaron E. Carroll, M.D., in a 2019 article in JAMA Forum.

“They start to ignore them because if everything causes an alert, then they stop having any real meaning,” Carroll wrote.

In a 2017 video posted by the Institute for Healthcare Improvement (IHI), Bob Wachter, M.D., of the University of California, San Francisco details the challenges in telling meaningful alerts from needless ones. At UCSF, doctors may see 30,000 alerts a month and pharmacists, 160,000 alerts.

“We touted alerts and alarms as being one of the main advantages of computerization,” Wachter said. “And I think right now, it’s a disaster.”

Wachter is among those who have urged a thorough reconsideration of the alerts clinicians see. For more on this, please see this WIRED series, based on Wachter’s “The Digital Doctor” book. It includes details of Wachter’s discussion with Boeing engineers about the strict standards that prevent airline pilots from being overwhelmed by alerts. The Joint Commission, which accredits hospitals, has repeatedly highlighted the risk of alarm fatigue, including making this a top priority among 2021 patient-safety goals. For a good recap of the state of efforts to address alert fatigue, see the “alarm fatigue” chapter in AHRQ’s Making Healthcare Safer III: A Critical Analysis of Existing and Emerging Patient Safety Practices.

Diagnostic error

Estimates indicate most people in the United States might experience a meaningful diagnostic error at some point in their lives, sometimes with devastating consequences, according to a key 2015 report on this topic from the National Academies of Sciences, Engineering, and Medicine. These kinds of errors can prevent or delay appropriate medical treatment and also trigger unnecessary or harmful procedures and tests.

Clinicians make the wrong calls about patients’ health for a variety of reasons, including the biases they bring to their work and misunderstandings during discussions.

The accuracy and the timeliness of diagnoses also depend greatly on the conditions in which doctors, nurses and other medical professionals practice medicine, noted the federal Agency for Healthcare Research and Quality (AHRQ) in a 2022 brief. Variables that can make diagnostic errors more likely include chaotic workplaces and rushed visits and flawed electronic health records (EHRs). Steps that may help reduce diagnostic errors include engaging patients more in discussions about their medical care through steps such as sharing visit notes, AHRQ said. The federal agency also recommended increased cooperation and teamwork, such as clinicians engaging directly with laboratory professionals and radiologists for guidance and assistance on selecting tests, interpreting results.

The Society to Improve Diagnosis in Medicine and the Leapfrog Group are among the organizations looking to reduce cases of inaccurate and delayed identification of serious health conditions. In a 2022 report, the Leapfrog Group, a patient-safety organization founded by large employers and other major purchasers of health care, highlighted examples of medical centers that had taken significant steps to reduce diagnostic errors. At University of California San Diego, for example, the Post-Handoff Reports of Outcomes project uses the EHR to create summaries for clinicians that lists patients recently under their care and highlights outcomes after the patient was handed off to another clinician.

Another concern is underdiagnosis, which involves delayed or missed diagnosis of a medical condition. This can lead to There may be missed diagnosis of acute myocardial infarction in women or missed diagnosis of depression in Black patients.

Differential diagnosis

A list of possible conditions that could be causing a patient’s symptoms.

A differential diagnosis is a systemic process that helps clinicians make correct and timely diagnoses and avoid harm from missing or delaying a diagnosis or making an incorrect diagnosis. A good differential diagnosis can guide clinicians in deciding when to order tests and how to discuss their uncertainty with a patient. In some health care systems, clinicians lack sufficient time to perform all steps that may be needed for a differential diagnosis: carefully taking a patient’s history, researching alternative conditions, and consulting with colleagues who may offer contrasting ideas. Some electronic health records have features that are meant to support differential diagnoses, such as trigger tools that flag patients who are at risk of serious diseases.

Hospital-acquired conditions

People too often suffer medical complications in hospitals that might have been avoided with better care. These include infections, sepsis, bedsores (pressure sores) and falls that result in injuries. Medicare has in recent years sought to dock pay for hospitals considered to have a high number of cases of hospital-acquired conditions.

Even with significant efforts by the U.S. government in recent years to combat hospital-acquired conditions, people still suffer harm during their stays. There were 86 hospital-acquired conditions, also called HACs, per 1,000 discharges for 2017, according to the Agency for Healthcare Quality and Resources (AHRQ). That’s a rate of almost one in 11 patients suffering some kind of harm during their stays, with adverse drug reactions and bedsores being among the most common complications.

The U.S. government raised the financial stakes for hospitals for failing to protect patients as part of the 2010 Affordable Care Act. The law requires that the hospitals in the worst-performing quartile on scores for hospital-acquired conditions lose 1 percent of their Medicare payments for inpatient care.

There’s been continuing debate about how the Centers for Medicare and Medicaid Services (CMS) judges hospitals and how well this penalty has worked to reduce harm to patients. Jordan Rau of Kaiser Health News in February 2022 dug into many of these issues in his story, “Health Care Paradox: Medicare Penalizes Dozens of Hospitals It Also Gives Five Stars.”

Medical error/preventable adverse event

Medical error is commonly defined as “the failure of a planned action to be completed as intended or the use of a wrong plan to achieve an aim.” Medical errors that result in injury are called preventable adverse events.

According to a 2015 article by two prominent patient safety researchers, “The exact number of preventable deaths is difficult to estimate because valid and standardized measures for the major causes of preventable death are lacking and because it is difficult to separate inevitable from preventable harm.”

Yet it’s clear that preventable harm is common and often undetected. A rigorous review of medical records by researchers at Brigham and Women’s Hospital estimated that 7% of hospitalized patients experienced preventable adverse events. Such incidents can have devastating emotional consequences for patients, families, and clinicians.

Recognition that all clinicians commit errors has led to efforts to move the health care industry away from punitive “blaming and shaming” of people in favor of promoting a culture of transparency and systemic improvement. However, resistance to such change persists. A criminal conviction of a Tennessee nurse for administering the wrong drug to a patient, which resulted in the patient’s death, has come under heavy fire by clinician and patient safety groups.

Near miss

Incidents that would have led to an adverse event if it hadn’t been for luck or early detection far outnumber adverse events themselves. They also provide important learning opportunities.

Some experts consider near misses to be as important as adverse events for identifying unsafe conditions and implementing safety improvements. However, reporting of near misses is scattershot. Some organizations require or encourage staff members to report near misses, but clinicians may be reluctant to do so for various reasons including time and fear of punishment.

Never event/serious reportable event

Some adverse events do serious harm and are considered to be entirely preventable. Examples are surgery on the wrong site or wrong patient, an instrument or swab retained in a patient’s body, or the wrong dose of a medication.

In a seminal 2000 report, To Err Is Human, the Institute of Medicine recommended the creation of a national mandatory reporting system, using data collected by states, to track the frequency of adverse events that cause death or serious harm.

The National Quality Forum, a nonprofit private-public partnership, responded two years later by releasing a list of events that it termed “serious reportable events,” or “never events,” extremely rare medical errors that should never happen. That list was updated in 2011, with a total of 29 events focusing on surgical or invasive procedures, product or device events, patient protection events, care management events, environmental events, radiologic events, and potential criminal events.

As of 2008, 26 states had active, mandatory systems for hospitals to report serious adverse events to oversight authorities, although the types of reportable events and objectives of reporting programs varied. Notably, Minnesota publicly reports the number of “never events” by hospital. No nationwide reporting system has been established.

Patient harm

This is a blanket term for harm to a patient that results from medical care or a failure to provide appropriate care. It usually refers to physical harm but may also apply to psychological or even financial harm.

The HHS Office of the Inspector General defines patient harm as any harm to a patient as a result of medical care or in a health care setting, including the failure to provide needed care. According to the HHS Office of the Inspector General, the term refers collectively to adverse events and temporary harm events.

Less understood are emotional harms that patients and their families may experience due to a medical error.

Prior authorization

Insurers sometimes ask doctors and other clinicians to provide more information about intended treatments and medicines for patients before agreeing to pay for these services and products. The goal of this prior authorization is spotting unsafe or inappropriate treatments, which often may not be consistent with evidence or guidelines, according to insurers. But doctors and many patients say the way insurers implement their prior authorization systems have created obstacles that can deny or delay needed care, while putting significant time-consuming administrative burdens on medical practices and consumers.

Health plans often have rules that can protect people from overuse and misuse of treatments and services. Prior authorization has been used for example to try to keep opioid use in check and to prevent prescriptions of medications that can interfere with other types of drugs or potentially worsen existing conditions, according to an FAQ from the trade group America’s Health Insurance Plans (AHIP)

But there also are concerns about how health plans implement prior authorization. Doctors and other medical professionals often face significant hurdles in trying to get needed drugs and treatments for their patients.

Surveys done by American Medical Association (AMA) have found many doctors say delays due to prior authorization have resulted in harm to patients. In some cases, insurers have instituted prior authorization policies for common procedures and approved almost many requests, leading to questions about the need for these restrictions in some cases. A review by a federal watchdog unit found almost one in five -- or 18 percent -- of prior authorization requests denied by insurer-run Medicare Advantage plans actually fell within coverage and billing rules.

Overdiagnosis, Overtreatment

There’s been growing awareness in recent years of the risk posed to patients from exposure to tests and treatments that were not crucial for them and may expose them to risk. The National Library of Medicine (NLM) defines overdiagnosis as labeling people as having disease or conditions in cases that would not cause them harm if left undiscovered, creating new diagnoses by medicalizing ordinary life experiences or lowering thresholds to define illness without evidence of improved outcomes. People get no medical benefit from overdiagnosis, which may experience physical, psychological and financial harm, NLM said.

NLM also in 2022 defined “overtreatment” as being procedures done too frequently or excessively often as a result of “overdiagnosis.”

“Overdiagnosis has been around as long as there has been diagnosis. But its recognition as a specific concept is a relatively new phenomenon,” wrote Steve Woloshin, M.D., and Barnett Kramer, M.D., in a 2022 opinion article in The BMJ.

Woloshin and Kramer have been among the leaders in efforts to get doctors and patients to reassess how aggressively some medical conditions must be treated, or even in some cases if a reading on a test truly means someone has a disease. There’s been a reassessment, for example, of how often men should be tested for prostate cancer and in what circumstances they need aggressive treatment for this condition.

The ABIM Foundation’s Choosing Wisely campaign represents efforts by dozens of medical societies to reduce unnecessary medical tests, treatments and procedures. JAMA Internal Medicine’s longstanding ”Less is More “ series highlights the ways that overuse of medical care can harm patients.

Staffing shortages

The stresses of the pandemic are considered likely to cause more doctors, nurses and other health professionals to retire early or seek to move away from clinical care in hospitals and medical offices. This will worsen what many experts saw as troubling shortages of medical staff even before COVID-19 hit. The nonprofit group ECRI put staffing shortages at the top of its list of its 2022 patient safety concerns.

The challenges of sustaining the U.S. health care workforce were known before the pandemic took hold. In February 2020, for example, researchers predicted that the United States could have a shortage of 139,160 physicians within a decade.

Writing in the Atlantic in November 2021, Ed Yong recapped some of the pandemic experiences that led people to leave medicine, including belligerent acts by people skeptical of the SARS-CoV-2 virus and the vaccines that work against it. “Even after they’re hospitalized, some resist basic medical procedures like proning or oxygenation, thinking themselves to be fighters, only to become delirious, anxious, and impulsive when their lungs struggle for oxygen,” Young wrote, and then quoted a nurse thinking of leaving the profession. “Once, Americans clapped for health-care heroes; now “we’re at war with a virus and its hosts are at war with us.”

As of the week ending March 20, 2022, 28 percent of U.S. nursing facilities reported at least one staffing shortage, or approximately 3,900 out of 14,000 facilities, according to a brief from the nonprofit Kaiser Family Foundation. There was a flurry of news coverage about salaries paid to nurses willing to travel and take temporary assignments during the pandemic. But there’s a need to dig deeper into the decisions made by hospital administrators that have left many nurses willing to leave long-term employment, and in some cases, the field of medicine, argued journalist Sarah DiGregorio in a March article in the Washington Post.

“Many hospitals have kept “their nursing staff as lean as possible, treating the nursing workforce like a tap they can turn on and off to maximize profits,” DiGregori wrote. “Ping-ponging from furloughs and layoffs to cutting hours and then to mandatory overtime is not a recipe for retention. The understaffing crisis is a circular problem: Not hiring enough nurses makes working conditions unbearable, leading to more nurses leaving their jobs.”

Vaccine Adverse Event Reporting System (VAERS)

The COVID pandemic drew new attention to the system the U.S. Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) use to monitor how vaccines work. The Vaccine Adverse Event Reporting System (VAERS) takes reports from members of the public as well as medical professionals and patients. Due in part to the broad-based system of collection, VAERS will sweep in cases where people report medical complications and conditions that may ultimately be found unrelated to vaccines they received. There’s been notable concern about members of the public misinterpreting VAERS reports and spreading misinformation about vaccines.

Established in 1990, VAERS can serve as an early warning system, with its wide reach helping doctors and researchers more easily pick up signals of rare side effects of vaccines, such as anaphylaxis and Guillain-Barré Syndrome (GBS). VAERS is “good at detecting unusual or unexpected patterns of reporting that might indicate possible safety problems that need a closer look,” the Department of Health and Human Services (HHS) said in an FAQ on VAERS.

VAERS data helped doctors adjust the childhood polio vaccine schedule in 1997 in response to about eight to 10 cases of vaccine-induced paralysis they learned had been occurring annually, according to the CDC’s published reports. That change greatly reduced the rare instances of severe side effects after polio vaccinations, wrote journalist Amy Dusto in a May 2022 explainer for the Johns Hopkins Bloomberg School of Public Health, titled “What VAERS Is (And Isn’t): The public database of reported post-vaccination health issues is often misused to sow misinformation.” VAERS also aided in the detection of rare cases of myocarditis following the second dose of COVID-19 mRNA COVID vaccine.

But VAERS is not designed to determine if a vaccine caused an adverse event, as both the HHS FAQ and Hopkins explainer note. It’s critical to remember that a report about a person experiencing a medical condition after vaccination does not establish a link between the two. The COVID vaccine has seen significant misinterpretation of the VAERS data. The database is open to the public and can be searched.

“Since it’s so transparent, people don’t really understand what it’s for,” Kawsar Talaat, M.D., co-director of clinical research for the Hopkins Institute for Vaccine Safety said in the university’s explainer. “They think it’s things that are vetted and have causal relationships with the vaccine.”