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Patient Harm Remains Pervasive in Hospitalized Medicare Patients, a New Federal Report Shows

Health Letter, November 2022

By Azza AbuDagga, Ph.D.

Image: Olena Yakobchuk/Shutterstock.com

It has been 23 years since the National Academy of Medicine, then the Institute of Medicine, sounded the alarm on patient safety, indicating that “health care in the [U.S.] is not as safe as it should [and] can be.” That assertion was based on studies that estimated that every year, at least 44,000 — and perhaps as many as 98,000 — individuals die in American hospitals due to medical errors that could have been prevented.

Since then, federal agencies embarked on various programs to improve patient safety and reduce patient harm. Although these efforts have curbed certain types of medical errors, preventable permanent and temporary patient harm continues to be a major threat in the American health care system.

In May 2022, an important, long-anticipated report by the Office of Inspector General (OIG) of the Department of Health and Human Services (HHS) showed that patient harm is widespread among hospitalized Medicare patients.

The OIG report details

The new report was based on an in-depth review of medical records pertaining to 770 Medicare patients who were discharged from nearly 630 hospitals in October 2018 (the average length of stay among these patients was five days). These patients were randomly selected from over 1,076,300 Medicare patients who were discharged from short-term acute-care hospitals during the one-month study period.

To identify patient harm, OIG reviewers examined medical records of the selected Medicare patient sample in a two-stage process. First, registered nurses screened these records and flagged 393 patient admissions that contained certain trigger events (clinical clues, such as a fall, laboratory test showing dangerously low blood glucose levels, intubation [insertion of a tube in the airway to aid with breathing], pressure ulcer or unplanned return to surgery) that may be indicative of patient harm, which includes adverse events and temporary-harm events. The report defined adverse events as harm to a patient due to medical care or in a health care setting, including failure to provide needed care, that led or contributed to an undesirable clinical outcome — such as prolonged hospital stay, permanent harm, life-saving intervention or death — that is not caused by the original condition. It defined temporary-harm events as events that resulted in patient harm and required medical intervention but did not extend hospital stays, cause permanent harm or require lifesaving intervention.

In the second review stage, physicians assessed the medical records of each flagged patient admission and determined whether the identified events were preventable (could have been avoided if the patient had received better care, such as improved assessment or alternative actions).

Accordingly, the OIG report estimated that 25% of the Medicare patients discharged in October 2018 experienced at least one adverse event or temporary harm during their hospital stays. Of those, 12% experienced adverse events and 13% experienced temporary-harm events. Some patients (8%) experienced multiple unrelated adverse events or temporary-harm events.

The report indicated that 45% of the adverse events and 41% of the temporary-harm events were preventable. About one-third of these overall events were associated with substandard or inadequate care provided to patients. An example of a preventable adverse event due to substandard care is a patient who was given three different opioid medications after surgery for a fractured ankle, rendering that patient unresponsive.

The report found that 43% of preventable overall patient-harm events were related to medications. These events commonly involved patients who experienced delirium (confusion, disordered speech or hallucinations), low blood pressure, acute kidney injuries or excessive bleeding. The remaining preventable harm events involved problems with patient care, procedures or surgery, or infections.

The report estimated that 10% of the adverse events (both preventable and unpreventable) contributed to Medicare patient deaths. This translates to 14,800 patients (1% of all hospitalized Medicare patients) in October 2018. Remarkably, out of 11 death-associated adverse events in the Medicare sample, seven were preventable. All seven patients experienced a series of “cascade” events — a chain of events initiated by an unexpected result or other incident that triggered harm — leading to death. For example, a patient with sepsis did not receive adequate fluids and antibiotics (which is the standard treatment for this condition), leading to subsequent septic shock, respiratory failure and death.

The report found that 23% of patients who experienced overall harm events, either preventable or unpreventable, required further treatment that led to Medicare costs that were incurred during the initial hospital stay or additional stays to address the harm. Overall, the report estimated that Medicare spent hundreds of millions of dollars on hospital costs associated with patient-harm events, many of which were preventable, during October 2018. Additional costs associated with medications, physician office visits and rehabilitation services during and after the study period were not included in the report. Furthermore, these events likely increased patient costs (such as coinsurance and deductible payments) as well.

The report uncovered serious gaps in the two policies that the Centers for Medicare and Medicaid Services (CMS), the federal agency that oversees Medicare, has set up as payment incentives for harm prevention based on rates of certain hospital-acquired conditions. Specifically, of the overall harm events discovered in the OIG report, only 5% were captured in the harm-event list of the first policy (Hospital-Acquired Condition Reduction Program) and only 2% were captured in the harm-event list of the second policy (Deficit Reduction Act Hospital-Acquired Condition). The report concluded that because these policies use “narrowly scoped” lists of hospital-acquired conditions and use limited criteria for recognizing harm events, they are not sufficiently effective in supporting safety for Medicare patients.

Report recommendations

The OIG report stated that HHS leaders and agencies must act urgently to reduce patient harm in hospitals. It made three recommendations to CMS: (1) to update and broaden its lists of hospital-acquired conditions to capture common, preventable and high-cost harm events; (2) to explore expanding the use of patient-safety specifications for health care payment and service-delivery projects; and (3) to develop and release interpretive guidance to surveyors for assessing hospital compliance with requirements to track and assess patient harm.

Also, the report made four recommendations to the Agency for Healthcare Research and Quality (AHRQ): (1) to coordinate efforts to update the agency’s quality strategic plans, (2) to optimize the use of quality and safety review systems, (3) to develop an effective model to disseminate information on national clinical practice guidelines or best practices to improve patient safety and (4) to continue its efforts to identify and introduce new tactics to prevent frequent patient harm in hospitals.


Given that a 2010 OIG report found comparable levels of preventable patient harm among Medicare patients, it is unacceptable that preventable patient harm remains persistent among these patients.

It remains to be seen how well HHS and its agencies will heed the OIG’s call to prevent unnecessary patient harm and related wasted resources among hospitalized Medicare patients in the foreseeable future.

For now, it is dismaying that in their responses to the OIG recommendations, neither CMS nor AHRQ even allude to a zero-patient-harm goal, a necessary aim for any health care program, especially one like Medicare that covers vulnerable patients.