Has Inpatient Care Become Safer?

It's hard to believe that more than 30 years have passed since the Harvard Medical Practice Study (HMPS; N Engl J Med 1991; 324:370) — the first large study to document a high incidence of medical errors in U.S. hospitals — was published. Using data from the HMPS and other studies, the Institute of Medicine's seminal work “To Err Is Human” put patient safety in the consciousness of practicing physicians and the lay public. During the past 3 decades, much has changed in healthcare. With the advent of electronic health records, I no longer occupy my day searching for paper charts, and I have witnessed the standardization of many safety protocols (e.g., surgical checklists, practices to prevent catheter-related bloodstream infections). But have these interventions made hospitals safer?

To provide a more contemporary perspective on inpatient safety, researchers now have published a retrospective cohort study in which they assessed the frequency, preventability, and severity of patient harm in a random sample of admissions from 11 Massachusetts hospitals, ranging from small (<100 beds) to large (>700 beds) during the 2018 calendar year (N Engl J Med 2023; 388:142). At least one adverse event (defined as unintended physical injury from medical care that required additional monitoring, treatment, or hospitalization, or that resulted in death) occurred in nearly 24% of a random sample of 2800 admissions. Among 978 adverse events, 23% were judged to be preventable. Nearly one third of adverse events were considered to be serious (i.e., required substantial intervention or prolonged recovery), and 5% were life-threatening or fatal. A preventable adverse event occurred in approximately 7% of all admissions. Adverse drug events were the most common (39% of all adverse events), followed by surgical or other procedural events (30%), patient-care events (i.e., falls, pressure ulcers; 15%), and healthcare-associated infections (12%). When adverse events occurred, they were associated with a doubled mean length of stay (9 vs. 4 days).

Comparing the event rates in the current study with those in the HMPS and other studies is fraught with challenges. For example, in the current study, researchers only examined events that occurred during hospitalization, whereas the HMPS also included outpatient events that resulted in hospitalization. However, the current study used a more expansive definition of error, and it was conducted in an era better suited to detect and track certain adverse events (e.g., healthcare-associated infections). In short, the easier it is to look for errors, the more you will find. Nonetheless, gaps still exist in our ability to identify certain adverse events reliably. For example, reviewers in the current study detected errors in clinical reasoning that led to adverse events in only 10 cases — surely an underestimate.

In the end, are hospitals of today safer than they were several decades ago? Perhaps, but the continued high incidence of in-hospital adverse events suggests that progress has been incremental at best. Over time, hospitals have become increasingly complex, severity of illness is likely greater, and many newer diagnostic and therapeutic interventions carry considerable risk, making room for error even less. And we can add to this mix other relevant factors, such as staffing shortages, financially imperiled hospitals, and various economic incentives that don't always align with patient safety. Lastly, many U.S. hospitals still rely solely on voluntary reporting of adverse events. Computerized triggers and artificial intelligence embedded in electronic records already are being used and probably will be implemented more widely in years to come.

Developing better approaches to identifying and preventing adverse events — while renewing efforts to uphold a strong patient-safety culture — are essential. The results of this retrospective study remind us there is much work left to be done if we are to keep our patients out of harm's way.