Prevoo et al., 1995
Modified disease activity scores that include twenty-eight-joint counts
- Objective
- The development and validation of Modified Disease Activity Scores (DAS) that include different 28-joint counts.
- Related articles
- Articles showing that the DAS28 is too quick to categorise patients as in remission due to, e.g., residual pain and power Doppler activity. TODO add more articles on validation of DAS28.
- Link
- DOI: https://doi.org/10.1002/art.1780380107
Background
- At the time, the only other available disease activity score included two comprehensive joint counts, i.e., the Ritchie Articular Index (RAI) and the total number of swollen joints.
- Recent studies had indicated that joint counts consisting of only 28 joints are as valid as more comprehensive joint counts.
- The present article aims to develop and validate a disease activity score based on these less comprehensive joint counts.
Methods
This section will mostly focus on the development of the scores and less on the validation.
Patients
Inclusion critera were as follows:
- recent-onset RA (disease duration of less than one year)
- no previous DMARD-treatment
This resulted in a sample size of 227 patients from one clinic, and 97 patients from another clinic.
Variables
| Patient-reported outcomes | Lab measures | Joint counts | Treatment data |
|---|---|---|---|
| Global health (VAS) | ESR | Ritchie Articular Index | Start of DMARD or NSAID |
| Morning stiffness | Thrombocyte count | Total tender joints (53 joints) | Change of DMARD or NSAID |
| Grip strength | Albumin | Total tender joints (44 joints) | Stop of DMARD or NSAID |
| HAQ | Hemoglobin | 28 swollen joint count | Start of DMARD or NSAID |
| \(\alpha_1\)-globulin | 28 tender joint count | ||
| \(\alpha_2\)-globulin | |||
| \(\beta\)-globulin | |||
| \(\gamma\)-globulin |
Construction of scores
According to the authors, the most important feature of a disease activity score is to discriminate between high and low disease activity.
- High
- The clinician decides that the patient should start DMARD treatment or change DMARD treatment
- Low
- The clinician decides that the patient stop DMARD treatment because of remission, or existing DMARD treatment was unchanged.
Two periods of high and two periods of low disease activity were randomly chosen per patient with a time period of >1 year (not sure what “time period” refers to here).
This DAS was obtained from canonical discriminant analysis and from logistic discriminant analysis. The same procedure was performed for both comprehensive and 28-joint counts to compare the resulting scores.
Conclusion
- We all know the result! A very popular score.
- TODO add more details.