Medicaid mortality rates significantly higher after major surgery

Medicaid patients had higher mortality after major surgeries than other patients, according to Primary Payer Status Affects Mortality for Major Surgical Operations, a new study from researchers at the University of Virginia Health System in Charlottesville. The study was published in the September 2010 issue of Annals of Surgery.1

From 2003 to 2007, 893,658 major surgical operations were evaluated using the Nationwide Inpatient Sample database, including lung resection, esophagectomy, colectomy, pancreatectomy, gastrectomy, abdominal aortic aneurysm repair, hip replacement, and coronary artery bypass.

The researchers found that patients with Medicaid payer status had a higher risk of in-hospital mortality and complications. Medicaid patients accrued higher costs compared to uninsured and Medicare patients, even after accounting for patient risk factors.

"We do not believe there is a simple explanation," says Damien J. LaPar, MD, the study's lead author and a surgery resident physician in the Division of Thoracic and Cardiovascular Surgery at the University of Virginia.

The researchers accounted for many potential factors that may impact surgical outcomes, such as patient health and co-morbid diseases, socioeconomic status and income, regional hospital differences, and race. Despite these adjustments, Medicaid patients had the highest odds of mortality among Medicaid, Medicare, private insurance, and uninsured patients.

"Discrepancies in patient outcomes as a function of payer status are likely due to subtle, complex interactions between a number of patient and health system-related issues," says Dr. LaPar. For example, these patients may have more advanced disease when they present, may have a limited support network after surgery, and may be getting their care at different centers compared to other patients.

Reasons are complex

Terry Conway, MD, a Chicago-based principle of Health Management Associates and former chief operating officer of the Ambulatory and Community Health Network at Cook County Bureau of Health Services in Chicago, notes that the compared outcomes in this study were for serious surgeries that are likely to be done to non-pregnant adults, which is not the major population that is in Medicaid. Also, people with serious illnesses often go onto Medicaid because of their condition, which is not the case with Medicare and commercial insurance.

"There are significant differences there. Medicaid is coverage that people characteristically go on and off of," says Dr. Conway. "So, the people in Medicaid were likely to have not been covered for a long time and have underlying illnesses. That was controlled for, but what wasn't controlled for is how well they were cared for in the past. So, these differences could be due to how well this population was treated."

Another possibility is that the providers or hospitals that did the surgery were not high quality or lacked the resources of facilities that see primarily Medicare and commercial insurers, Conway says.

"Given that Medicaid enrollees have a number of characteristics that put them at a higher mortality risk, it is not surprising that they experience higher mortality rates, even after adjusting for the comorbidity measures that are available on the hospital discharge abstract," says Genevieve M. Kenney, PhD, a senior fellow and health economist at The Urban Institute in Washington, DC.

However, Dr. Kenney notes that the study does not include a full set of controls for socioeconomic status and related health risks. "Therefore, the study does not take into account the possibly confounding factors that are likely linked to Medicaid enrollment," says Dr. Kenney.

Dr. Kenney points to greater poverty rates among Medicaid enrollees and their much higher rates of mental and physical health problems as likely contributors to their higher mortality rates.

"In addition, relative to Medicare and private-pay patients, Medicaid patients may be receiving care from different hospitals and/or surgeons, or may be receiving a different mix of services and procedures," says Dr. Kenney.

ID root causes

Dr. Kenney says that future research should be aimed at sorting out the roles played by unobserved health risks and other related risks, by differences in the mix of hospitals and surgeons treating Medicaid patients, and by differences in the mix of services provided to Medicaid surgical patients.

"It will be important to narrow the study population to a group that is more homogenous than the one studied here, so as to develop an appropriate comparison group for the Medicaid patients who were studied," says Dr. Kenney. "And it would also be important to look at within-hospital mortality rates to identify root causes of mortality differences."

While Dr. Kenney doesn't think that the study provides conclusive evidence of a causal link between payer source and mortality, she says that the paper indirectly raises a number of important questions related to hospital-based patient safety and quality of care that are of importance to Medicaid programs.

"It brings out the importance of carefully controlling for the characteristics of the Medicaid population and the providers they use, when comparing their service use and outcomes to that of other payers," says Dr. Kenney.

Patricia MacTaggart, a lead research scientist and lecturer in the Health Policy Department at George Washington University in Washington, DC, says that in general, the study authors address variables that are consistent with other studies, such as volume being an indicator of quality.

"The study discussion also acknowledges identified limitations that are critical for analysis," notes Ms. MacTaggart. For instance, many elderly and disabled Medicaid are "dually eligible" for Medicare and Medicaid, and these were counted in only one payer source in the study.

The study also acknowledges that the data source accuracy is limited by the fact that many Medicaid enrollees gain their eligibility retroactively as a result of their hospitalization. "Thus, Medicaid individuals may not be tracked in the correct category," says Ms. MacTaggart. "More importantly, they may have had less preventive care coverage than someone who had Medicare or private insurance coverage prior to the hospitalization."

Most states have been analyzing high-cost, high-utilization inpatient services based on their Medicaid data for some time, says Ms. MacTaggart. "What is added in this study is the comparison data from other payers," she says.

Various states utilize Medicare Hospital Compare, The Leapfrog Hospital Survey, Healthcare Cost and Utilization Project, and the Healthcare Effectiveness Data and Information Set measurement data to do similar analyses and comparisons for the hospitals in their states in order to make decisions regarding coverage and payment.

"While inpatient hospital coverage has a significant immediate cost impact on Medicaid, outcomes of inpatient hospital stays have an even more substantial impact on Medicaid costs long term," adds Ms. MacTaggart.

Improve quality

"Medicaid directors and policy makers should be aware of these findings, including the fact that major operations in these patients appear to be more costly," says Gorav Ailawadi, MD, senior author of the study and faculty member at the University of Virginia's Division of Thoracic and Cardiovascular Surgery.

More importantly, Medicaid payer status may serve as a proxy for larger, health care system-related issues that could be targeted to improve surgical outcomes for Medicaid recipients. Further identification of "culprit factors" may help to improve patient morbidity and mortality following major surgical operations, for both Medicaid and uninsured patients, explains LaPar.

"We would likely require prospective data to identify opportunities for improvement," adds Dr. LaPar.

Dr. LaPar says that patients and physicians should "know and understand the influence of primary payer status during preoperative patient risk stratification." He would like to see further investigation of this complex issue aimed at identifying modifiable factors to improve patient outcomes.

"Look at what is happening nationally now. People are looking at reorganizing the way care is delivered," says Dr. Conway. For example, accountable care organizations are paid extra if they achieve quality — but save costs. This is mostly happening in the Medicare and commercial world, however, while uninsured and Medicaid patients are seen at health systems known as the "safety net" says Dr. Conway.

"This is not a high-quality approach, and it is an expensive approach," says Dr. Conway. "This population had worse outcomes and a longer length of stay. If I were a Medicaid director, I would try to expedite the safety net by looking into building delivery systems that would produce accountable care."

Dr. Conway notes that the fact that more money is spent doesn't necessarily mean that health status improves. "You've got to do more specific things, and they have to happen within the delivery system," he says.

Medicaid needs to become more involved in the transformation of the safety net medical delivery system, as is being done in the Medicare and commercial world, says Dr. Conway.

"It looks like, too, in the future, that even CMS [the Centers for Medicare & Medicaid Services] itself would like to see the safety net do this more; but they can't do it alone, because Medicaid is not strictly a federal program," says Dr. Conway. "Start looking at the delivery system that you provide payment to, and see what you could do to foster more accountable care."

Dr. Kenney says that it will be important for states and local areas with large projected Medicaid enrollment increases in 2014 to address provider capacity issues. "Those gaining Medicaid coverage in 2014 will likely be subject to many of the same disadvantages that may be contributing to the results of this study," she says. "Therefore, it will continue to be important to evaluate program performance with these caveats, and to identify Medicaid policies that help families successfully overcome access barriers."

As "meaningful use" measures move forward, hospitals will provide additional standardized measurement results across payers. This will provide another data source for quality initiatives, beyond the tools currently available.

Medicaid agencies and hospitals will be targeting hospital-acquired infections and addressing payment limitations required under new federal law, says Ms. MacTaggart. "Information such as this could be valuable, even with the limitations, not necessarily in comparison to other payers, but as a source of additional information across payers," says Ms. MacTaggart.

Ms. MacTaggart says workforce demand is one of the biggest potential concerns of state and federal Medicaid leaders in preparation for 2014 expansions, particularly related to specialists. "This study just highlights why focusing on this potential issue is critical. Targeted strategies are needed," says Ms. MacTaggart. "For this particular area, '2014 is now.'"


1. LaPar DJ, Bhamidipati CM, Mery CM, et al. Primary payer status affects mortality for major surgical operations. Ann Surg 2010;252(3): 544-551.

Contact Dr. Conway at (312) 641-5007 or, Dr. Kenney at (202) 261-5568 or, Dr. LaPar at (434) 924-9307 or, and Ms. MacTaggart at (202) 994-4227 or