While states mull over decisions on health insurance exchanges, another decision is looming on the horizon - whether or not to expand Medicaid as the Affordable Care Act (ACA) calls for.

Many governors have held off until after the election to make their decisions, with a number of states like Texas and Florida deciding not to, but the majority still remains undecided. Though the ACA calls for the federal government to foot 90 percent of the cost, the remaining 10 percent still represents an increase in states' costs in the midst of a dire budgetary crisis plaguing much of the country.

Budgets, however, are not the only decision rule states should be using to determine whether or not to expand their Medicaid rolls. Medicaid's track record on access to care and health outcomes is generally poor when compared to private insurance, and these measures often end up being only slightly better than for those who are uninsured, and are often statistically insignificant.

A study released today in the Journal of the American Medical Association (JAMA) looked at postoperative morbidity rates for patients that received surgeries for brain tumors, controlling for the insurance status of the patient. The results? At first glance, unsurprising. After fully adjusting for patient characteristics and comorbidity, uninsured patients were 2.62 times as likely (a hazard ratio of 2.62) to die after surgery as those with private insurance.

While in the adjusted analysis, the results for Medicaid recipients were not statistically significant (the results found Medicaid patients 2.03 times as likely to die relative to those with private insurance, but were not significant at the 5 percent confidence level [analogous to a 95 percent confidence interval]), the original, unadjusted  analysis (which doesn't take into account differences in patient characteristics) shows no statistically significant difference between Medicaid patient survival rate and the uninsured (2.6 percent and 2.3 percent, respectively).

This is yet another study that sheds light on the relatively poor outcomes of patients on Medicaid, which may not be significantly better than those of the uninsured. The relatively poor outcomes should come as no surprise, as Medicaid's lower reimbursement rates for specialists tends to cause significant access to care problems. And poor access to care will likely make Medicaid patients on the whole less healthy than those with private insurance, increasing the chances that they will have other complications that may lead to higher mortality.

A critique in JAMA brings up important issues that need to be taken into account. Of relevance is one in particular - the number of uninsured patients who enrolled in Medicaid during their hospital stay; these patients would be better categorized as being uninsured rather than having Medicaid. Nonetheless, the results echo what many have been arguing for some time - that Medicaid delivers poor outcomes that are cost-inefficient for states.