EROSION LOCATION, DOES IT MATTER FOR DIAGNOSING RA | Arthritis Information
SAT0010 EROSION LOCATION, DOES IT MATTER FOR DIAGNOSING RHEUMATOID ARTHRITIS?
M. M. Thabet*1, T. W. J. Huizinga1, A. H. M. van der Helm-van Mil1, D. van der Heijde1
1Rheumatology Department, Leiden University Medical Center, Leiden, Netherlands
Background: Early diagnosis of rheumatoid arthritis (RA) as well as prediction of RA development in patients with undifferentiated arthritis (UA) is essential to initiate early DMARD therapy that was shown to impede progression of joint damage and progression to RA. Recent reports concluded that the 1987 ACR classification criteria are not well suited for the classification of early RA. Noteworthy is that these criteria only include erosions in the hands and excludes feet.
Objectives: To investigate the value of the location of bone erosions for prediction and early diagnosis of RA development in UA patients.
Methods: Baseline radiographs of hands and feet of 518 UA patients were evaluated for the presence of erosions in the joints evaluated by the Sharp van der Heijde method. Presence of erosions was summarised in the following joint groups: wrist, metacarpophalangeal (MCP), proximal interphalangeal (PIP) and metatarsophalangeal (MTP) joints. After 1 year, patients were classified according to the 1987 ACR criteria.
Results: After 1 year follow up 160 patients developed RA, 87 patients developed other diseases and 271 patients remained as UA. The frequency of baseline erosions in UA patients in different joint groups, stratified by disease outcome after 1 year is summarised in the graph. In the group that developed RA, MTPs showed the highest frequency of erosions (26.3%) versus 10-11.3% in other joint groups. While in those who developed other diseases, MCPs had the highest frequency of erosions (12.6%) versus 4.8-10.3% in other joint groups. The predictive & diagnostic value of erosions by location is illustrated in the table. MTPs exhibited the highest sensitivity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratios (LR+) and lowest negative likelihood ratio (LR-). 13.1% of the patients that developed RA had erosions in the MTPs only.
Table:
| Predictive & diagnostic value of erosions by location |
Location |
Sensitivity |
Specificity |
PPV |
NPV |
LR+ |
LR- |
|
| Wrist |
10 |
95.4 |
80 |
36.6 |
2.2 |
0.94 |
| MCPs |
11.3 |
87.4 |
62.1 |
34.9 |
0.9 |
1.02 |
| PIPs |
11.3 |
94.3 |
78.3 |
36.6 |
1.96 |
0.94 |
| MTPs |
26.3 |
89.7 |
82.4 |
39.8 |
2.54 |
0.82 |
|
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