The DirectAccessMD clinic that serves the employees of Anderson County, SC, is run by a tireless advocate for, and deep believer in DPC, Dr J Shane Purcell. Here the employer, with Dr Purcell’s apparent support, has taken steps that seems to have somewhat mitigated the selection bias that is baked into most other direct primary care option arrangements. Specifically, the dual benefit plans here have both a lower deductible ($250) and a lower co-insurance maximum ($1250) for DPC patients than for non-DPC patients ($500, $2500). Where other benefit plans structures, like the Nextera SVVSD plan reported here, push higher risk patients away, the Anderson County plan is more welcoming to those patients. I applaud the County and Dr. Purcell.
In fact, a high risk Anderson employee can see more than $1500 per year in added costs if she declines DirectAccessMD. A patient expecting the average utilization seen for the FFS cohort (~$4750) in Anderson County would likely incur about $375 in added costs by declining DPC, where an average patient in Nextera’s SVVSD plan would have saved $925 for doing the same. Again, this important difference is a feather in Dr Purcell’s cap.
Yet, as the recent Milliman study suggests, high risk patients may be reluctant to disrupt standing relationships with their PCPs, and may choose to resist other incentives if it means having to select a new PCP from a small panel at a given DPC clinic. Consider also that older employees, even those not at high risk, are more likely than younger employees both to have deeper attachments to their long-standing PCP and to have more disposable income to spend on keeping that relationship going. On average, therefore, we would expect employees who eschewed the direct primary care package to be an older and/or riskier group. Let’s go to the tape.
Not surprisingly, raw data — without any risk adjustment — from the employer indicates a noticeably smaller percentage of purported savings than has been bragged about by other DPCs in the past. Anderson County’s net cost for DPC members came in at 9% less than for non-DPC members, but the employees in DPC paid OOP only about half of what their non-DPC counterparts did. Combining both employer and employee costs, the average total spend for Anderson County DPC patients came to about 14% less than for non-DPC patients, purported savings of $56 a month.
But note these warning from the Milliman study: “We urge readers to use caution when reviewing analyses of DPC outcomes that do not explicitly account for differences in population demographics and health status and do not make use of appropriate methodologies.” Or this more recent one: “It is imperative to control for patient selection in DPC studies; otherwise, differences in cost due to underlying patient differences may be erroneously assigned as differences caused by DPC.”
An risk analysis of the health status of all the county’s patients, fully detailed as to all chronic coniditions, may not have been financially feasible for a modest operation like Dr Purcell’s. But a sensible population demographic methodology is at hand: comparing the ages of the two populations and using that as a predictor of utilization. This is certainly a “rough approximation”. But, not only is a rough risk adjustment likely to be far better than no risk adjustment at all, the reasonableness of using age as a proxy for predicted utilization is affirmed by the fact that nearly all DPC practices use age-cost bands, and no other risk-based factor, in setting their subscription rates. Basic demographics are at the core of risk adjustments used by CMS for the ACA; over 75% of ACA enrollees in insurance plans under 65 have no adjustment-worthy chronic conditions; they are risk-adjusted on demographics alone.
The coefficients for age/sex risk adjustment used by CMS for ACA plans in 2020 can be seen here. And here is a copy of Dr. Purcell’s slide pointing out the DPC cohort of Anderson County employees was 2.7 years younger than the traditional cohort. Going back to the tape, I have computed that the expected overall medical costs for the DPC membership were 11.8% lower than for traditional primary care group. Subtracting that from raw savings of 14.1%, and a fair measure of the DPC savings for Anderson County is 2.3%, $9 PMPM, less than 20% of what Dr. Purcell has widely bragged.
The DirectAccessMD/Anderson County benefit plan made the direct primary care option more welcoming for riskier patients. That lead to a reduced level of selection bias and, accordingly, a reduced level of selection bias artifact masquerading as cost savings attributable to the direct primary care model. Even so, the amount of selection bias that remained amply supports adding the Anderson County DPC option “study” to the list of “studies” that have simply failed to support DPC brags of cost effectiveness.
I’ve referred elsewhere to my training as a scientist, which compels the engagement of any data presented that runs counter to a presented hypothesis. At some point in scientific history it became acceptable to stop listening respectfully to those who said the earth was flat.