The Oregon Health Study

The Oregon Health Study will demonstrate what happens when low-income persons transition from the ranks of the uninsured to having insurance. It offers an opportunity to predict what might happen in the next few years once federal rules expand eligibility for Medicaid to another 17 million Americans.

Oregon has recently opened its Medicaid program, the Oregon Health Plan Standard, by allowing the application of about 30,000 names drawn randomly from its waiting list.
Such an expansion allows for an analysis akin to a randomized controlled trial of expanding public health insurance coverage for low-income adults.  Such an analysis is of obvious interest with the adoption of the recent federal expansion of Medicaid due to the Patient Protection and Affordable Care Act.  Oregon offers the first opportunity for a randomized evaluation of such an expansion.

The only other randomized study of health insurance in the United States,, was completed in the mid-1970s and followed participants for three to five years.  The RAND study did not allow for the analysis of the impact of having no insurance at all, unlike the Oregon Health Study which seeks to compare the treatment group to a “no coverage” group.  Data can be collected from this “no coverage” group through administrative databases that have been maintained on those persons from the waiting list.  Data will be collected through late 2010.

There is concern for extrapolation of the findings of this study to the national expansion of Medicaid.  Initial comparisons were made between the low income uninsured adult population of Oregon and the low-income uninsured population of the United States.   The health care environment in Oregon was noted to be similar to that in other states as far as number of public hospital admissions, amount of uncompensated care as a fraction of gross hospital charges, and number of physicians per 100,000 residents.  The main difference noted between the Oregon and national populations is one of race, with Oregon having a higher percentage of whites than that of the country as a whole.   Another area of possible contention is that the Oregon Medicaid expansion is voluntary, as opposed to the mandate imposed by the federal health reform.  Such a difference might influence the type of person applying through the federal expansion program.

Individuals in Oregon who joined the waiting list were older and sicker than the overall target low-income population of Oregon.  Second, individuals in Oregon from the waiting list reported incomes that were much higher than those of the low-income uninsured populations of Oregon or the United States.  Actual enrollment in the program was low because many applicants from the waiting list were not eligible, for reasons including incomplete paperwork, unqualified income, or procurement of alternative insurance.

Commentary

The prospects of the Oregon Health Study will lead to a fascinating though limited set of data that will only be applicable to populations, insurance plans, health care environments and enrollment mechanisms that are similar to that of Oregon.

The acknowledgement of these limitations prior to the completion of the data collection is commendable – and should continue by means of more than the traditional statement of weaknesses at the end of future papers.  As other states will be expanding under the federal legislation, the federal government might consider an additional requirement of data analysis from the onset with similar methodology and sought outcomes.  Thereby, a national mapping of real time information can be collected and compared for effectiveness.

Allen H, Baicker K, Finkelstein A, Taubman S, and Wright BJ.  What the Oregon Health Study Can Tell Us about Expanding Medicaid.  Health Affairs 2010; 29 (9): 1498-1506.

by Kameron L. Matthews, MD, Esq.