Adverse Events Found in 23.6% of Massachusetts Hospitalizations

Researchers found that 22.7% of adverse events among inpatients were preventable.

Despite three decades of efforts to improve patient safety in the hospital setting, adverse events remain common, according to a new journal article.

The Harvard Medical Practice Study (HMPS), which was published in 1991, was one of the first comprehensive examinations of patient safety in the hospital setting. The study found there were 3.7 adverse events per 100 admissions, with 28% of the adverse events caused by negligence.

The new journal article, which was published by the New England Journal of Medicine, is based on data collected from 11 Massachusetts hospitals with beds ranging from fewer than 100 to more than 700. The researchers examined a random sample of 2,809 admissions.

The journal article has several key findings:

• There was at least one adverse event in 23.6% of the 2,809 admissions
   
• Out of the 978 adverse events identified, 22.7% were deemed to be preventable and 32.3% were considered serious (causing harm that required intervention or prolonged recovery)
   
• Among the preventable adverse events, 19.7% were serious, 3.3% were life-threatening, and 0.5% were fatal
   
• Adverse drug events accounted for 39.0% of adverse events, followed by surgical or other procedural events (30.4%), patient-care events such as falls and pressure ulcers (15.0%), and healthcare-associated infections (11.9%)
   
• The mean length of stay for inpatients experiencing at least one adverse event was significantly longer than for inpatients who did not experience an adverse event (9.3 days versus 4.2 days)
   
• Adverse events resulting from a surgical or other procedure were most likely to be life-threatening, and healthcare-associated infections were most likely to be fatal
   
• Patient-care adverse events and adverse drug events were more likely to be preventable than other types of adverse events

Adverse events remain common, and more work is needed to reduce them, the journal article's co-authors wrote. "Adverse events were identified in nearly one in four admissions, and approximately one fourth of the events were preventable. These findings underscore the importance of patient safety and the need for continuing improvement."

Interpreting the data

Adverse events remain a serious problem at hospitals more than three decades after the publication of the HMPS, the journal article's co-authors wrote. "Three decades after the HMPS drew attention to the issue of health care–associated patient harm, in-hospital adverse events continue to be common, and although only approximately one fourth of the adverse events identified in this study were deemed to be preventable, all adverse events negatively affect medical care and outcomes."

Although there have been many advancements in healthcare since the publication of the HMPS, patient safety remains a concern, the co-authors wrote. "Over the course of this 30-year interval, care has become more complex, and diagnostic and therapeutic options to treat disease and alleviate human suffering have advanced. The healthcare delivery system itself has changed dramatically with the advent of [electronic health records] and the movement of complex care to ambulatory sites, which has resulted in the most severely ill patients being treated in acute care hospitals. Despite stunning advances in medical science, we still have important gaps in patient safety."

Hospitals need to improve methods of identifying and assessing some adverse events, the co-authors wrote. "Measuring adverse events in a reliable and efficient way and developing standard approaches to the identification of and focus on preventable adverse events are critical to supporting persons charged with improving safety. Some types of adverse events, such as health care–associated infections, can be identified much more effectively than others, which suggests a need to improve routine tracking, especially for events such as adverse drug events."

There are several opportunities to improve patient safety, the co-authors wrote. "There is considerable variability among hospitals in adverse event rates, with larger sites having rates of approximately 40% or higher; this finding suggests that if hospitals had data that were more reliable and more routinely collected, it is possible that monitoring could be improved, adverse event rates could be reduced, and improvement strategies could be shared through careful study of interventions. Other key organizational elements such as safety culture and strong leadership with respect to safety and quality are also needed to advance performance."

The new research should be considered a rallying cry, they wrote. "Our findings are an urgent reminder to all healthcare professionals of the need for continuing improvement in the safety of the care we deliver."

Related: Researchers Find Decreased In-Hospital Adverse Events From 2010 to 2019