How frequently do Medicare hospital patients experience unintended harm or injury related to their medical care?

Among Medicare beneficiaries hospitalized during 2003, rates of 10 adverse events ranged from less than 1 percent of all hospital patients who suffered a bloodstream infection to 14 percent of patients who suffered complications after hip joint replacement surgery. Three of the 10 adverse event rates increased and five rates decreased from 2002 to 2003.

Why is this important?

The Institute of Medicine reported in 1999 that thousands of Americans are harmed each year from the health care that is intended to help them (IOM 1999). The IOM called for specific actions to improve patient safety, such as better information on system vulnerabilities so that they can be proactively mitigated and eliminated.

The Medicare Patient Safety Monitoring System (MPSMS) is a nationwide surveillance program intended to help achieve this goal for the Medicare program. The MPSMS uses explicit review of hospital medical records and administrative data to determine rates of specific adverse events of importance to the Medicare population (Hunt et al. 2004).

Findings

Among Medicare beneficiaries hospitalized during 2003, rates of 10 high-priority adverse events ranged from less than 1 percent of all hospital patients who suffered a bloodstream infection to 14 percent of patients who suffered complications after hip joint replacement surgery. Three of the 10 adverse event rates increased and five rates decreased from 2002 to 2003 (AHRQ 2005).

Implications

Although the occurrence of some adverse events may be related in part to patients' underlying medical conditions, many might be prevented with good surgical and nursing care. In two studies that reviewed medical records of hospital patients in New York State, Utah, and Colorado, more than one-half of the detected adverse events were judged to be preventable (Leape et al. 1991; Thomas et al. 1999).

A patient-oriented approach to patient safety recognizes that the patient's ultimate concern is freedom from harm. "Physicians and organizations should strive to prevent or mitigate situations that actually cause harm to patients, whether the harm is caused by an error or a faulty or inefficient process," says patient safety expert Roger Resar, M.D. (quoted in Neveleff, 2003).

Improvement Ideas and Resources

Research and experience suggest that adverse events can be greatly reduced and in some cases eliminated through actions that help instill a "culture of safety" within an organization, such as by creating systems that reliably provide evidence-based treatment, promoting good teamwork and communication, and encouraging reporting of and learning from mistakes (Gaba 2000; Helmreich and Merritt 1998; McCarthy and Blumenthal 2006b, 2006a; Reason 1997).

For example, the Veterans Health Administration (VHA) promotes improvement in surgical care by rigorously measuring comparative data on surgical outcomes in VHA medical centers and identifying and disseminating best practices. This approach was associated with a 45 percent decrease in postoperative complications and a 27 percent decrease in the 30-day death rate for veterans undergoing major surgery between 1994 and 2002 (Khuri et al. 2002).

Measure:

The denominators are hospitalized Medicare fee-for-service beneficiaries at risk of certain adverse events. The numerators are the subset of the denominator population who experienced the adverse event, defined as an "unintended harm, injury, or loss that is more likely associated with [the patient's] interaction with the health care delivery system than from an attendant disease process" (Hunt et al. 2004). Adverse events are identified using explicit clinical criteria applied to random samples of medical records.

• Complications of joint replacement include postoperative infections, postoperative pneumonia, postoperative urinary tract infection, postoperative deep vein thrombosis or pulmonary embolus, dislocation, wound complications other than infection, nerve injury, postoperative bleeding requiring four or more blood transfusions, cardiovascular complications, same side revision during the index hospital stay, return to the operating room for reasons other than same side revision during the index hospital stay, and death.
• Postoperative pneumonia and ventilator associated pneumonia events exclude patients admitted with tracheostomies.
• Central venous catheter–associated mechanical adverse events include allergic reaction, tamponade, perforation, pneumothorax, hematoma, shearing off of the catheter, air embolism, misplaced catheter, thrombosis/embolism, knotting of the pulmonary artery catheter, arrhythmia requiring treatment during insertion, bleeding, equipment malfunction, and pain.
• Postoperative venous thromboembolic events include pulmonary embolism or deep vein thrombosis occurring postoperatively during the hospital stay and readmission of surgical patients within 30 days for pulmonary embolism or deep vein thrombosis.

For more information, see the measure specifications.

Limitations:

These data do not include adverse drug events and do not reflect the experience of Medicare Advantage plan members. The occurrence of some adverse events may be related, in part, to patients' underlying conditions and the risk inherent in some treatments. These rates are not directly comparable to the Patient Safety Indicators data reported elsewhere on this Web site because of differences in methods and data sources.

Source:

The Medicare Patient Safety Monitoring System, a project of the Centers for Medicare and Medicaid Services, draws data from a national random sample of medical records for all fee-for-service Medicare hospital discharges (stratified by state) and from Medicare administrative data for post-discharge surveillance (such as hospital readmissions). Results were reported by the Agency for Healthcare Research and Quality (AHRQ 2005).

References:

* Indicates source of data used in the chart(s).* AHRQ (Agency for Healthcare Research and Quality). 2005. National Healthcare Quality Report, 2005. AHRQ Publication No. 06-0018. Rockville, Md.: U.S. Department of Health and Human Services.

Gaba, D. M. 2000. Anaesthesiology as a Model for Patient Safety in Health Care. BMJ 320 (7237): 785–8.

Helmreich, R. L., and A. C. Merritt. 1998. Culture at Work in Aviation and Medicine. Burlington, Vt.: Ashgate.

Hunt, D., N. Verzier, S. Abend et al. 2004. Fundamentals of Medicare Patient Safety Surveillance: Intent, Relevance, and Transparency. Baltimore, Md.: Centers for Medicare and Medicaid Services.

IOM (Institute of Medicine). 1999. To Err Is Human: Building a Safer Health Care System. Washington, D.C.: National Academy Press.

Khuri, S. F., J. Daley, and W. G. Henderson. 2002. The Comparative Assessment and Improvement of Quality of Surgical Care in the Department of Veterans Affairs. Archives of Surgery 137 (1): 20–7.

Leape, L. L., T. A. Brennan, N. Laird et al. 1991. The Nature of Adverse Events in Hospitalized Patients. Results of the Harvard Medical Practice Study II. New England Journal of Medicine 324 (6): 377–84.

McCarthy, D., and D. Blumenthal. 2006a. Committed to Safety: Ten Case Studies on Reducing Harm to Patients. New York: The Commonwealth Fund.

McCarthy, D., and D. Blumenthal. 2006b. Stories from the Sharp End: Case Studies in Safety Improvement. Milbank Quarterly 84 (1): 165–200.

Neveleff, D. J. 2003. Strategies Aim to Reduce Harm to Patients. QualityIndicator.com.

Reason, J. 1997. Managing the Risks of Organizational Accidents. Burlington, Vt.: Ashgate Publishing Co.

Thomas, E. J., D. M. Studdert, J. P. Newhouse et al. 1999. Costs of Medical Injuries in Utah and Colorado. Inquiry 36 (3): 255–64.