One of the initiatives in the Affordable Care Act of 2010 is the expansion of community health centers to provide primary care to millions of newly insured, low-income Americans. The same law promotes the patient-centered medical home model. A community center’s qualifications to be classified as a patient-centered medical home are evaluated through an assessment tool developed by the National Committee for Quality Assurance (NCQA) and endorsed by the federal government.

How well does this tool measure performance on a range of services? A new study, released yesterday as a Web First by Health Affairs, explores that relationship, sampling a group of community health centers in Los Angeles and focusing on diabetes care. It finds no significant relationship between how well these centers performed on the assessment and whether they achieved a range of process or outcome measures for diabetes care.

Robin Clarke and her coauthors at UCLA’s David Geffen School of Medicine collected data at thirty community health centers in Los Angeles County, studying a total of 1,455 diabetic patients. All of the community health centers studied would have qualified as NCQA patient-centered medical homes. The authors observed substantive differences in the quality of diabetes care across the community health centers when checking whether patients had received standard diabetes care evaluations such as blood pressure, HbA1c, or LDL-c testing; kidney disease screening; or eye examinations. However, the presence of more NCQA patient-centered medical home components was not associated with better delivery of diabetes care measures.

“One explanation is that the NCQA tool does not measure the processes that determine the quality of diabetes care with enough sensitivity for a community health center,” conclude the authors. They suggest that future demonstration projects “evaluate how effective enabling services are at overcoming barriers to care and improving chronic disease outcomes.”