Patient-Centered Medical Homes in statewide populations have unstoppable momentum and major constituencies in support of them, so valid analysis of their outcomes is probably as futile as it will be unwelcome. However, the math speaks for itself, at least in the mother of all statewide medical homes, North Carolina Medicaid’s Community Care Access Model.
I write this after having analyzed the actual data from this project’s outcomes report, rather than the stated conclusion of the report, a conclusion that continues to be cited in support of the many states considering or implementing medical home models for their Medicaid populations.
The conclusion makes North Carolina looks like a huge win for PCMH: $300-million in reported savings. However, readers should have (but largely didn’t) observe a number of curiosities about the data in support of that conclusion:
(1) Every element of resource use declined. People have to be getting their care from somewhere, but inpatient, ER, outpatient, physician, drug, and other expenses somehow all declined vs. trend.
(2) The decline in physician practice expense is especially counterintuitive: Why are the doctors so supportive if they are working harder but making less money?
(3) Even though somehow savings were shown in physician expense, per capita doctor visits did indeed increase. More concerning was that specialist visits –which are supposed to decline in a PCMH model – also increased.
(4) Inpatient expense fell 47%. This was achieved despite the fact that all the AHRQ’s “Ambulatory Care –Sensitive Conditions” total to about 20% of admissions in most populations.
(5) The evaluators (William M. Mercer) are on record as saying that “choice [emphasis mine] of trend has a large impact on estimates of financial savings.” Perhaps it is possible that Mercer, having given themselves this latitude, “chose” a trend that would make the study look good.
Those observations merely suggest that the study was done wrong. But one other “finding” invalidates the entire study: the 54% reduction in spending on babies under one year of age, accounting for the majority of the entire $300-milllion in spending. (Any nontrivial savings whatsoever in this category should have raised eyebrows since PCMH is mostly about managing chronically ill patients.) The components of spending in that category include physician expense, which should rise since doctors get paid more to be more accessible, and drug expense, which should rise for the same reason. This means that the entire 54% savings across the category must be concentrated in neonatal expense. Since neonatal expense is about half of total spending in the age category, it would have to decline by a mathematically impossible 100%+ in order for the category to average a 54% reduction.
But perhaps the neonatal savings came close to 100%. To determine that, let’s do something the investigators didn’t do: Look at the actual data. Neonatal admissions and days of care, by state, are freely available at http://hcupnet.ahrq.gov/HCUPnet.jsp. It turns out that the percentage of neonatal admissions and days fell only 1%, from 27.5% in the baseline to 26.5% in the last year studied—a decline two orders of magnitude less than was required to make Mercer’s math work. (The argument that neonatal utilization would have risen absent a PCMH program is also invalid – South Carolina enjoyed a relative decline in neonatal utilization as well over that same period, without a medical home.)
Therefore, without even needing to “challenge the data,” but rather just looking that the data that the consultants presented, as well as other public sources of data, one must conclude that the study is fatally flawed.
What do proponents of this study say in defense? In a private conversation with one of the major proponents of a PCMH model (whose company benefits greatly from adoption of electronic health records), the response was that he “believed” the Mercer outcomes. Math, however, is not a belief system. It’s as proof system, and every assumption about the savings from widespread implementation of statewide medical homes in the Medicaid population has just been proven wrong.