“I remodeled that index for our population,” he explains. “I found out that if you combined the percentage of change in disease activity, using this index, with the degree of disease activity attained, you could come up with a correlation between genetic markers and response markers.”2
When Less Can Be More
The oral versus parenteral gold trial was a small study, and Dr. van Riel wanted to investigate whether the disease activity index could be improved by studying a larger patient population for a longer period of time. (The follow-up on the smaller trial was only one year.) The team at Radboud was interested in starting investigations on a larger cohort of patients with early rheumatoid arthritis and following them intensively every month for a longer period.
Work began on this project in 1987, when Désirée van der Heijde, MD, PhD, now professor of rheumatology at University Hospital Maastricht in the Netherlands and a renowned outcomes researcher, was a PhD candidate under Dr. van Riel’s supervision. Dr. van der Heijde recalls the time as very exciting: “We started with a database with a lot of numbers and figures and had to find out how to construct a combined disease activity score and then do all the analysis. At each step in the research, we had to define how to do that step, and then the next step.”
She recalls many long hours spent in front of the computer screen with statistician Martin van‘t Hof, PhD, to develop the DAS, which was always discussed and supervised by Dr. van Riel. Dr. van Riel, who was what the Dutch call a “promotor,” or supervisor of her PhD thesis, was “always available for discussions” about the work, she says. The first DAS included the Ritchie articular index, the 44 swollen-joint count, the erythrocyte sedimentation rate, and an assessment of the patient’s general health using a visual analog scale, and was developed during Dr. van der Heijde’s PhD work.3,4 She later to moved to another medical center after she had completed her rheumatology training at Radboud.
Since that time, the DAS has been extensively validated and has undergone several refinements. Dr. van Riel continued on to develop the DAS28, which uses 28 joint counts to monitor disease activity.
Dr. van Riel also worked hard to promote the DAS concept as a tool for assessing disease progression in trials and clinical practice. The DAS28 continues to be used as an instrument for monitoring treatment with DMARDs and biologicals. “If you ask 10 people to comment on Piet van Riel,” says Robert Landewé, MD, associate professor of rheumatology and clinical rheumatologist at the University Hospital in Maastricht and consultant rheumatologist at the Atrium Hospital in Heerlen, “I’m sure that 10 out of 10 will come up with [the association of] the Disease Activity Score, which was invented by Désirée van der Heijde under his supervision,” he says. “The fact is that he has promoted the Disease Activity Score as the measure of choice in the EULAR [European League Against Rheumatism] community, and proposed that EULAR adopt response criteria analogous to the ACR response criteria.”
