Like every other health policy nerd out there, I’ve been following the debate over the Oregon Medicaid experiment results about as closely as most Chicagoans followed the Bulls game. For those not up to speed, here’s a quick replay:
- Due to financial constraints, Oregon was only able to expand Medicaid enrollment by 10K in 2008, though many more people were eligible to enroll, so they only allowed people to enroll by lottery.
- Social scientists quickly realized that this was the ideal “randomized controlled trial” of Medicaid (or any health insurance) anywhere, and started tracking the outcomes of the 10K that won the lottery and some of those that did not.
- They published their results last week, and now everyone is either convinced that Medicaid definitely works or that it definitely doesn’t. Some have described this as the Rorschach test for whether you are someone who believes in Medicaid (and by extension, health care reform), or doesn’t.
The results of the study, most simply put by the study itself, are that the study authors:
found no significant effect of Medicaid coverage on the prevalence or diagnosis of hypertension or high cholesterol levels or on the use of medication for these conditions. Medicaid coverage significantly increased the probability of a diagnosis of diabetes and the use of diabetes medication, but we observed no significant effect on average glycated hemoglobin levels or on the percentage of participants with levels of 6.5% or higher. Medicaid coverage decreased the probability of a positive screening for depression (−9.15%; p=0.02), increased the use of many preventive services, and nearly eliminated catastrophic out-of-pocket medical expenditures.
As others have already blogged extensively, there are a very good mathematical reasons for why the study was not able to achieve statistical significance, even when many of their desired outcomes did move in the direction they were hoping. Mainly, the study was underpowered (i.e. did not have enough people to achieve statistical significance), particularly since the experimental group ended up being relatively healthy (Only about 7% had hypertension and only about 5% had diabetes!) — not to mention the numerous other limitations revealed when one looks at the details of the study design in the appendix.
Other writers, especially physicians, have simply thrown up their hands and said, ‘look, we never said that health care insurance was anything more than a first step towards better health care for all.’ It reduces the financial burden of health care and prevents catastrophic out-of-pocket medical expenditures. It increases access to preventive services and starts people on the necessary medications for chronic conditions like diabetes — what else could you expect from just providing health insurance, when we haven’t yet solved the puzzle of health care quality or health care coordination?
I love the world of health services research, and respect all the commentators I’m linking to here, but I can’t help feeling like all this policy wonkish internal baseball is missing the point. How am I supposed to explain this to my patients or my friends that aren’t also social scientists? Am I supposed to go into how this highly limited study with gold standard methodology came up with this really convoluted result and what that (doesn’t) mean?