Jeffrey H. Silber, MD, PhD Contributes to Resident Hour, Colon Cancer Studies

The Children’s Hospital of Philadelphia’s Jeffrey H. Silber, MD, PhD, contributed to two recent studies that span the research spectrum. The first, published in The Journal of the American Medical Association (JAMA), investigated changes to the number of hours medical residents can work. The second investigation, of which Dr. Silber was the lead author and which appeared in the Annals of Internal Medicine, was a study of racial disparities in colon cancer survival.

In the JAMA study, Dr. Silber and colleagues found resident duty hour reforms did not result in significantly higher 30-day readmission or mortality rates. And with the Annals of Internal Medicine investigation, the researchers showed racial disparities in colon cancer survival did not decrease over a 14-year period, from 1991 to 2005.

A pediatrician and healthcare economist, since 1997 Dr. Silber has directed CHOP’s Center for Outcomes Research. He has published extensively on the use of multivariate matching in healthcare, and has applied this approach to outcomes research in both pediatric and adult medicine and surgery, disparities research, and cancer research. Dr. Silber is a professor of Pediatrics, Anesthesiology and Critical Care at the University of Pennsylvania Perelman School of Medicine and professor of Health Care Management at The Wharton School.

With the JAMA study, the researchers sought to determine whether 2011 reforms to the number of hours residents could work had affected patient mortality and readmissions. Implemented by the Accreditation Council for Graduate Medical Education (ACGME), the reforms maintained the 2003 maximum of 80 hours a week but reduced residents’ work limit from 30 to 16 consecutive hours for first-year residents, and to 24 hours for more experienced residents.

The investigators performed an observational study of Medicare patient admissions data from July 1, 2009 to June 30, 2012, comprising some 2,790,356 patients with 6,384,273 admissions across 3104 hospitals, and examined a number of medical conditions (such as congestive heart failure and diabetes) and surgical categories. They found “no significant positive or negative associations of duty-hour reforms” with 30-day all-location mortality or 30-day all-cause readmissions.

“There has been a lot of speculation about the effect of the 2011 ACGME duty hour reforms on patient outcomes, so we looked at death and readmission rates at the national level,” said the study’s lead author, the University of Pennsylvania’s Mitesh S. Patel, MD, MBA, MS.

“Some hoped that by shortening intern shifts from 30 hours to 16 hours, less fatigued residents would lead to less medical errors and improved patient outcomes. Yet, others were concerned that shorter shifts would increase patient handoffs and leave less time for education, thereby negatively affecting patient outcomes,” said Dr. Patel. “These results show that in the first year of the reforms, neither was true.”

Presentation to Blame for Colon Cancer Survival Disparities

 The Annals of Internal Medicine study, meanwhile, examined racial disparities in colon cancer survival rates.

Dr. Silber has previously investigated racial disparities in cancer survival. In August of 2013 he published a study in JAMA that showed differences in how breast cancer patients present at diagnosis are more responsible for racial disparities in 5-year survival than treatment disparities.

In the current study, Dr. Silber and colleagues — including the Wharton School of the University of Pennsylvania’s Paul R. Rosenbaum, PhD; and Penn Medicine’s Bruce J. Giantonio, MD — examined Survey, Epidemiology, and End Results (SEER) Medicare data from 1991 to 2005 across 16 sites to determine the extent to which colon cancer disparities result from presentation at diagnosis or treatment.

One of the most common forms of cancer, colon and rectal cancer account for approximately 10 percent of new cancer cases each year worldwide. According to the National Cancer Institute (NCI), five-year survival rates for colon and rectal cancer vary widely depending on how early it is detected. Based on data from 2004 to 2010, 89.8 percent of patients with localized cancer survived five years after being diagnosed, while only 12.9 percent of patients with distant or metastasized cancer survived five years. And during 2014 the NCI estimates 2014 there will be approximately 50,000 deaths from colon and rectal cancer.

Using SEER data, Dr. Silber and colleagues matched 7,677 black patients aged 65 and older with three groups of 7,677 white patients aged 65 and older — who were followed until 2009 — to investigate the roles of demographics, presentation, and treatment in survival. Finding a “persistent disparity,” the researchers’ data showed a 9.9 percent difference in five-year survival between black and white patients when matched for demographics. When matched for presentation the disparity was 4.9 percent, and when matched for treatment it was 4.3 percent.

“In conclusion, more of the racial disparity in colon cancer survival is explained by differences in health at diagnosis (both the state of the cancer and comorbid conditions) than by differences in subsequent treatment,” the authors write. “Our study suggests that the most effective route to reducing the racial survival disparity is to find ways to reduce the disparity in presentation, so fewer black patients present with advanced disease.”

To read more about the JAMA study, see Penn Medicine’s press release. And for more information about the Annals of Internal Medicine paper, see the journal.