There is an old gag about an intensely optimistic child whose bright outlook on life is so irrepressible that when he is presented with a room full of manure for Christmas, he screams with delight, convinced that there “must be pony in there someplace.”

I was reminded of that when I read the recent research report and the accompanying editorial in the Annals of Internal Medicine about the patient-centered medical home (PCMH).

A PCMH is a practice with enhanced care coordination and disease management, and official designation — which follows a rigorous certification process — is granted by the National Committee for Quality Assurance (NCQA). In recognition of the enhanced services provided by PCMHs, some insurers provide them higher rates for medical services.

Despite this, evidence that PCMHs actually provide better care has been hard to come by. A recent study in JAMA concluded that PCMH designation “was associated with limited improvements in quality and was not associated with reductions in utilization of hospital, emergency department, or ambulatory care services or total costs over 3 years.” Hardly a ringing endorsement.

The current study compared three kinds of primary care practices, all in the Hudson Valley of New York. One group were “level 3” PCMHs, meaning they had attained the highest level of certification. Another group had electronic medical records, which are a requirement for for PCMH designation, but were not themselves PCMHs, and the third group used paper records. The quality of care in the practices was assessed by their performance on a set of 10 process of care measures from the Healthcare Effectiveness Data and Information Set (HEDIS), which is also brought to you by those folks at NCQA. The study found that “the PCMH was associated with modest quality improvement” that was not attributable to the use of the EMR alone.

Here’s the problem. While the PCMH practices did better on a few HEDIS measures, that alone hardly seems to capture the quality of primary care. In addition, it is pretty hard to believe that the practices differed only in their PCMH designation, or use of an EMR. Does anybody really think that the kind of physician who would invest in an EMR and go through the transformation and certification necessary for PCMH designation is “just like” the physician who is still on paper? Seems to me that the observation is hopelessly confounded, and the conclusion therefore quite suspect.

I think the authors are just looking for the pony.

Ira Nash is a cardiologist who blogs at Auscultation.