The March Rheuminations column, “Twenty Questions, Part 1” inspired many letters from TR readers. Here are just a few of those responses.
DAS in Clinical Practice—Not Ready For Prime Time
Joint counts, DAS [Disease Activity Score], and other numeric measures of RA disease activity are important tools for research, but as currently developed, are not appropriate for clinical practice. There are several reasons, so I’ll start with the most important one first. We live in a complex world where many seemingly good ideas can have unintended consequences. Unfortunately, out in community medicine, managed care companies are using joint counts, sed rates, and CRPs [c-reactive proteins] to restrict the use of biologics. For example, one of my RA patients on [methotrexate] with two very swollen wrists and erosive disease was recently denied an anti-TNF because the joint count was too low.
Dr. Theodore Pincus has data showing that 40% of patients on anti-TNFs at Vanderbilt have normal CRPs, yet another one of my patients had an anti-TNF denied because his CRP was <2.0. If we established the physician global score—the modified HAQ [Health Assessment Questionnaire] plus the [Visual Analog Scale] as the “gold standard”—we could circumvent these managed care manipulations.
There are also concerns about what we are really measuring. The burden of inflammation in a patient with two hot knees clearly exceeds that of a patient with several swollen [proximal interphalangeals], yet the joint count, and hence the DAS, is lower. DAS and joint counts amplify the significance of small joint disease and can be very misleading in terms of clinical reality. We know that sed rates are “falsely” elevated in patients with high RFs, monoclonal gammopathies, those with liver disease, and the elderly. CRPs are high in the overweight patient and in patients with infections. In populations of patients (i.e., a study), these issues cancel out, and markers of inflammation correlate well with disease activity, but in individuals, they do not. In clinical practice it is all about the individual patient.
I also have practice management concerns. Joint counts add to our already burdensome documentation requirements. A statement like “the [metacarpophalangeals] are slightly swollen and tender, but the left knee still has a large, warm effusion” is perfectly adequate and makes for better reading than a table of 0s and 1s. Let’s make the joint-count table and DAS calculation a separately reimbursable procedure and you’ll see a lot more enthusiasm for their use.