Sixty-three disease-activity measurement tools were identified through a systematic review of the literature. Using exclusion criteria and comments from an expert advisory panel, that list was narrowed to 14 measures. After practicing rheumatologists rated nine of the 14 measures as useful and feasible, the working group identified six that had the best psychometric properties, including reliability, validity, and responsiveness. Those selected for the final list include the Clinical Disease Activity Index (CDAI), Disease Activity Score with 28-joint counts (DAS28), Patient Activity Scale (PAS), PAS-II, Routine Assessment of Patient Index Data with three measures (RAPID-3), and Simplified Disease Activity Index (SDAI).
Three of the six are patient-reported measures: PAS, PAS-II, and RAPID-3. The CDAI adds assessment by the physician, and SDAI and DAS28 include both physician assessment and laboratory values. Each of the six measures is also a composite measure, which can “reduce the risk that any one aspect of a patient’s disease drives the disease activity in one direction or another…to help prevent extreme results,” Dr. Kazi explains. The selection of six disease-activity measures should help “sort out the muddle that was out there with 63 possible tools,” he says. These six should also provide maximum flexibility to rheumatologists, with some measures completed by the patient in the waiting room, and others completed by both patient and physician.
“These measures are not perfect and are not a substitute for clinical judgment, but they can provide an additional tool to identify the patient’s current state of disease activity and provide a language that allows some consistency between physicians,” Dr. Kazi says. “We are doing our patients a favor by using a measure that is transportable from practice to practice.”
Other key points in the recommendations:
- Systematic use of these tools can help implement “treat-to-target” goals;
- Patient-reported measures take fewer than three minutes to complete and have simple mathematical scoring, but lack formal joint assessment;
- Patient-/provider-reported CDAI does not require an acute-phase reactant, but does require that providers conduct detailed joint counts consistently; and
- Both the SDAI and DAS28, conducted by the physician, include tender and swollen joints counts and an acute-phase reactant.
Dr. Kazi says physicians should find a disease activity measure “that works for your practice. Be consistent with it, and use it consistently and longitudinally with the same patient. We look at so many things to decide how a patient is doing, and this is one more tool that can help us take better care of patients.”
