More than 80 percent of hospitalized patients who tested positive for Clostridium difficile were tested outside the hospital or within the first 72 hours of hospitalization, suggesting that settings outside of the hospital may play key roles in the identification, onset and possible transmission of the disease, according to a new Kaiser Permanente study published today in the journal Mayo Clinic Proceedings.

The study provides new insight into the contagious and potentially deadly infection also known as C. diff, a bacterium most often associated with hospitals and other in-patient health care settings. It is one of the first to accurately identify a larger population of patients with C. diff by examining them in an outpatient setting as well as in the hospital.

“Kaiser Permanente’s integrated health care system allowed us to track patients after they left the hospital in both the outpatient health setting and during a readmission, which contributed an important new perspective to the current C. diff story,” said study lead author Sara Y. Tartof, PhD, of the Kaiser Permanente Southern California Department of Research & Evaluation. “Previous studies typically focused on diagnoses during a hospital stay, which tells only part of the story. These findings emphasize how important it is to test for the infection both in the hospital as well as in outpatient settings.”

Researchers examined the electronic health records of more than 268,000 Kaiser Permanente patients in Southern California who were admitted to 14 Kaiser Permanente hospitals between Jan. 1, 2011 and Dec. 31, 2012. Of these patients, 4,286 – or 1.6 percent – tested positive for C. diff. Researchers also found that 49 percent of C. diff cases were acquired in the community or from an indeterminate source and that 31 percent of cases were associated with a previous hospitalization.

“C. diff infection is a major public health concern in the U.S., with infection rates tripling over the last decade,” said Tartof. “This study’s comprehensive view gives a more complete picture of the extent of health care-associated infections.”

According to the Centers for Disease Control and Prevention, C. diff is a bacterium that most often affects sicker, older adults who take antibiotics and causes a range of symptoms including diarrhea, fever, loss of appetite and inflammation of the colon. People can become infected with C. diff by touching items or surfaces that are contaminated with the bacteria or through physical contact with health care workers who have picked up the bacteria from surfaces or other patients.

The CDC reports that over the past several years, states have noted higher rates of C. diff infection and an associated increased risk of death. Studies also show that C. diff infection accounts for considerable increases in the length of hospital stays and more than $1.1 billion in health care costs each year in the United States.

“Kaiser Permanente works diligently to prevent C. diff infections in both the hospital and ambulatory settings,” said Michael Kanter, MD, regional medical director of quality and clinical analysis, Southern California Permanente Medical Group. “We promote judicious use of antibiotics, we make painstaking efforts to ensure our staff and health care providers practice hand hygiene, we prompt testing of symptomatic patients, and we conduct vigorous cleaning of rooms with special cleaning agents known to kill C. diff when patients with the infection are identified.”

Kaiser Permanente can conduct transformational health research in part because it has the largest private patient-centered electronic health system in the world. The organization’s electronic health record system, Kaiser Permanente HealthConnect®, securely connects approximately 9.3 million patients to 17,000 physicians in 618 medical offices and 38 hospitals. It also connects Kaiser Permanente’s research scientists to one of the most extensive collections of longitudinal medical data available, facilitating studies and important medical discoveries that shape the future of health and care delivery for patients and the medical community.

Other authors of the paper include: Rong Wei, MA, Hung Fu Tseng, PhD, and Steven J. Jacobsen, MD, PhD, Kaiser Permanente Southern California, Department of Research & Evaluation; Kalvin C. Yu, MD, Kaiser Permanente West Los Angeles Medical Center, Department of Infectious Diseases; and Gunter K. Rieg, MD, Kaiser Permanente South Bay Medical Center, Department of Infectious Diseases.

About the Kaiser Permanente Southern California Department of Research & Evaluation

The Department of Research & Evaluation conducts high-quality, innovative research into disease etiology, prevention, treatment and care delivery. Investigators conduct epidemiology, health sciences and behavioral research as well as clinical trials. Areas of interest include diabetes and obesity, cancer, HIV/AIDS, cardiovascular disease, aging and cognition, pregnancy outcomes, women’s and children’s health, quality and safety, and pharmacoepidemiology. Located in Pasadena, the department focuses on translating research to practice quickly to benefit the health and lives of Kaiser Permanente Southern California members and the general population. Visit kp.org/research.

About Kaiser Permanente

Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of America’s leading health care providers and not-for-profit health plans. Founded in 1945, our mission is to provide high-quality, affordable health care services and to improve the health of our members and the communities we serve. We currently serve approximately 9.3 million members in eight states and the District of Columbia. Care for members and patients is focused on their total health and guided by their personal physicians, specialists and team of caregivers. Our expert and caring medical teams are empowered and supported by industry-leading technology advances and tools for health promotion, disease prevention, state-of-the-art care delivery and world-class chronic disease management. Kaiser Permanente is dedicated to care innovations, clinical research, health education and the support of community health. For more information, go to: kp.org/share.