3 MATERIAL Y MÉTODOS
3. Seguimiento clínico
claims data using 100 percent data and all
age groups
Only use claims that reflect an outpatient visit and have allowed
charges > $0.00
Merge with Physician to Speciality Crosswalk file for all physicians, including non-ACO providers; e.g., physician A —> Cardiologist
—> Medical Specialist (MDSP)
Eliminate claims with physician speciality indicating an ancillary care provider (e.g., pathology, radiology, or nuclear
medicine)
For each enrollee, find:
•
Number of visits per provider•
Date of last visit to each provider•
Number of days between first and last visit to each provider•
If no PRIM visits occurred, attempt first to assign patient to a Medical Specialist (MDSP)•
If no Medical Specialist visits, assign to a Surgical Specialist (SURG)•
In both cases, use the same algorithm as for PRIM assignment (at right)Check if
enrollee had at least one visit to a Primary Care Provider (PRIM)
Check if only one PRIM visit
Check if enrollee visited one PRIM more than any other
Is the largest number of visits to a given PRIM > 1? Assign
to PRIM with whom patient had most recent visit
Assign to PRIM with greatest length of time between first and last visit
Assign to PRIM Assign to this PRIM No Yes No Yes No Yes Yes No
For the Brookings-Dartmouth pilot sites, the participating payers and providers must agree to use this patient attribution methodology for ACO incentives. We recognize that different attribution models are in place for other delivery system reforms, such as the Patient-Centered Medical Home. While more testing is necessary, it appears reasonable for a provider system to use multiple attribution models for the various delivery system reforms they are participating in. For example, a provider system could use one attribution method for the medical home delivery system and a separate, distinct attribution method for the ACO delivery system. However, it is beneficial for all ACOs in an area to use the same attribution method to avoid having conflicts in patient assignment.
Exclusivity
It is important to note that the providers used for patient attribution should be exclusive to the ACO, while the providers not selected for patient attribution are free to participate in multiple ACOs. The exclusivity criterion allows for clearer evaluation of an ACOs performance and also alleviates
concerns over gaming. For example, imagine if a Medicare provider is used for patient attribution in two ACOs. It may become difficult to keep track of which ACO is accountable for his or her patients. Furthermore, if the patients happen to be high cost, each ACO may be incentivized to try and disassociate itself from them.
Critical Mass
Another critical issue with patient attribution is the number of patients that are attributed to an ACO. An ACO should have a sufficiently high number of patients attributed for two reasons. The first involves the ability to obtain statistically or even practically meaningful results on the cost and quality impacts of ACOs. The statistical issue will be discussed in more detail with the benchmarking and performance measurement discussion later in this section. The second reason involves increasing the likelihood of achieving a critical mass of patients to incentivize providers to change care processes.
Changes in core practice patterns and patient care management are expected under the ACO model. To support and reinforce the practice pattern changes, a sufficiently large percentage of the providers’ patients should be enrolled in the ACO. Based on anecdotal discussions with industry experts, estimates of the desired critical mass can be expected to vary widely, ranging from 20 percent to 60 percent of the patients at an office or clinic location to be enrolled in the ACO.
Reaching critical mass may require the inclusion of both Medicare beneficiaries and commercial members. While Medicaid should be considered, the complexity, payment rates, and other unique attributes may add obstacles including to Medicaid in some states.3
It should also be noted that many ACOs will be contracting with multiple payers. Arrangements with commercial payers will vary based on the location and the market of the ACO partners. Potential contracts may be negotiated with a commercial carrier for fully insured business, self- insured employer plans, or both. Although the characteristics of differing payers and membership may vary, the expected provider practice pattern changes and payment incentives should be aligned across all patients in the ACO.
It is also expected that ACOs will continue treating non-ACO patients. To the extent that non-participating payers benefit from the practice pattern changes adopted by ACO providers, their costs may drop without sharing the savings with the ACO providers, creating a “free rider” problem. There is thus an incentive for both ACOs and payers to achieve as much broad participation as possible.
Changes in Membership
After a patient has been attributed to a physician and the ACO, the assignment generally remains for a period of one year even if the patient changes his/ her care to providers outside of the ACO. Rules will be needed to make potential adjustments for patients who relocate, die, or lose coverage within
the year. Although ACOs may consider alternative timeframes for handling enrollment issues, any approach adopted must limit the ability to “dump” high-cost patients while giving providers the opportunity to impact their patients’ care.
It is expected that ACO membership would remain relatively stable on an annual basis. Over time, membership would grow through the addition of new payers, ACO providers, or new groups of patients from existing payers.