The authors concluded, "The majority of the variation in readmission was attributable to patient-related factors (82.8%) while surgical subspecialty accounted for 14.5% of the variability, and individual surgeon-level factors accounted for 2.8%."
The investigators looked at data for over 22,000 surgical patients treated at Johns Hopkins and found the overall rate of readmission within 30 days was 13.2%. After the exclusion of those who performed fewer than 21 operations per year, 56 surgeons made up the study cohort.
Multivariable analysis showed significant non-modifiable patient-related factors associated with readmission were African-American race/ethnicity, more comorbidities, occurrence of postoperative complications, and an extended length of stay.
Variation in readmission by subspecialty ranged from 2.1% after breast, melanoma, or endocrine surgery to 37% following cardiac surgery.
The authors pointed out that this study "echoes growing concerns regarding the use of readmission as a quality metric based on its current methods."
Let's compare it to the controversial ProPublica Surgeon Scorecard.
Both the Surgeon Scorecard and the JAMA Surgery paper used data from the years 2009 through 2013. The scorecard involved only eight high-volume low-risk in-patient procedures while the paper looked at in-patient surgery of all types.
From an article written by the authors of the Surgeon Scorecard: "If a patient was readmitted to any hospital (not just the hospital where the surgery was performed) within 30 days of a surgery for one of the conditions we identified, we counted the case as a complication for the surgeon who performed the initial procedure."
What we learned from the JAMA Surgery paper raises some questions about the the Surgeon Scorecard. On Twitter, I asked for comment from Marshall Allen, the lead author of a white paper [not peer-reviewed] describing the methodology of the Surgeon Scorecard.
Between attacks on my credibility because I choose to use a pseudonym, he said that they did not count most readmissions as complications. It is unclear from the article, the white paper, or its appendices exactly which complications were included. For clarification, we could ask the "surgeon experts" who advised ProPublica, but their names have not been disclosed. They are anonymous, just like me.
According to the white paper, surgeons were blamed for 64,367 (46%) of all complications incorporated into the Surgeon Scorecard. Table 3 of the white paper lists the 20 most frequent complications. The top three, comprising 26,795 complications, were postoperative infection, iatrogenic pulmonary embolism, and infection/inflammatory reaction due to internal joint prosthesis.
Other studies have shown that not all occurrences of those three complications are attributable to a surgeon's misdeed. Among the rest of the top 20 causes of readmission were postoperative pain, fever, and dysphagia (difficulty swallowing)—again possibly not the fault of a surgeon.
So the JAMA Surgery paper says surgeons are responsible for 2.8% of readmissions within 30 days, but ProPublica's self-published white paper says 46% of all readmissions are due to something a surgeon did or did not do.
Who to believe?
Note added at 7:27 a.m. on 9/2/15: See my next post for a clarification about causation and variation.
The full text of the peer-reviewed JAMA Surgery paper is available here.