Author: Chase Doyle
Lower socioeconomic status is associated with worse outcomes for patients undergoing abdominal aortic aneurysm repair in the United States, according to a retrospective study of more than 90,000 patient records. The results showed a significant increase in postoperative morbidity in poorer patients following this type of repair, with income level, primary payor status and race as independent risk factors.
“We believe this study demonstrates the importance of socioeconomic status as a factor in perioperative risk stratification,” said Matthew D. Perlstein, MD, an anesthesiology resident at NewYork-Presbyterian/Weill Cornell Medicine, in New York City. “While controlling for various other comorbidities and characteristics, income level, payor status and patient race were all found to be independent risk factors. Each of these characteristics individually puts the patient at risk for a higher readmission rate following AAA repair.”
Although other studies have shown that poorer socioeconomic status is a significant predictor of adverse outcomes in a variety of surgical procedures, the researchers aimed to update and expand upon previous findings concerning mortality after AAA repair, particularly the associations among race, income, primary payor status and postoperative hospital readmission.
Another Risk Factor: Emergent Repair
For this analysis, Dr. Perlstein and his colleagues used the hospitalization and discharge records of five states (California, Florida, Kentucky, Maryland and New York) from State Inpatient Databases (SID), the Healthcare Cost and Utilization Project, and the Agency for Healthcare Research and Quality. The researchers identified records of patients who underwent AAA repair between January 2007 and December 2014 (excluding California, ending December 2011). A generalized estimating equation was used to predict readmission at 30 and 90 days from income quartile, primary payor, race and other relevant covariates. To account for correlations between patients at the same hospital, the researchers clustered the data by hospital.
As Dr. Perlstein reported at the 2018 annual meeting of the Society of Cardiovascular Anesthesiologists (abstract 9), 92,028 patients were included in the study. When examined on income, patients in the lowest quartile were more likely to be readmitted to hospital than those in the highest quartile, at both 30 days (odds ratio [OR], 0.92) and 90 days (OR, 0.89).
Race also was an independent risk factor for readmission. Hospital readmission was significantly more common for black patients (OR, 1.36) and Hispanic patients (OR, 1.12), than for white patients at 30 days after discharge (P<0.0001). Similar findings were seen at 90 days, the authors noted.
Primary payor status was found to contribute independently as well. Readmission was more likely if patients were insured by Medicare (OR, 1.31) or Medicaid (OR, 1.48), or if they lacked insurance (OR, 1.23) after both time points, compared with patients who had private insurance.
In addition, the researchers evaluated disparities in surgical urgency of AAA repair. Results revealed that emergent repair was more common in the lowest income quartile (16.4%) than in the highest (13.4%) (P<0.001), as well as being more common for patients without private insurance. Emergent repair was needed in 13.7% of Medicare patients, 27.7% of Medicaid patients and 40.6% of uninsured patients, but in only 13.1% of privately insured patients (P<0.001). Furthermore, Dr. Perlstein said emergent repair was much more common in black patients (28.1%) and Hispanic patients (19.7%) than in white patients (13.4%) (P<0.001).
“This study highlights the need to address disparities in the health care system in order to improve clinical outcomes,” said Dr. Perlstein. “When controlled for individually, income level, primary payor status and race all put patients at risk for poorer outcomes. These three markers of socioeconomic status should be considered in the preoperative risk stratification of patients for AAA repair.”
Lisa Q. Rong, MD, a cardiac anesthesiologist at NewYork-Presbyterian/Weill Cornell Medicine, and senior author of the study, emphasized the need for future studies to elucidate the causal factors for differences in outcomes.
“In order to prove causation, we would need patients that were propensity matched, or we would have to collect data prospectively in a trial,” said Dr. Rong. “A prospective observational trial or a randomized trial would probably be the best option in trying to figure out causation. … There are advanced databases that are collecting ongoing prospective data that we hope to mine in the future.”