Background: Preliminary clinical criteria based on age, inflammation, and immobility have been proposed to identify which patients with rheumatoid arthritis (RA) should be examined by dual energy x ray absorptiometry (DXA) to diagnose osteoporosis. The three item criteria have not been evaluated in male patients with RA or in the entire female RA population.
Objectives: (1) To test the proposed criteria in a cohort of men and women thought to be representative of the entire underlying RA population. (2) To develop clinical decision rules, which could be applied to all patients with RA irrespective of corticosteroid use.
Methods: Clinical and demographic data were collected from a total of 287 representative patients with RA (235 (82%) women, 52 (18%) men, age range 25.3-73.1 years) from the Oslo RA register (completeness 85%). Bone mineral density (BMD) was measured in spine L2-4 (anterior-posterior view) and femoral neck by DXA. The criteria were applied and sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated.
Results: Mean age (SD) for the women and men with RA was 56.8 (11.0) years and 61.5 (10.2) years; disease duration was 15.5 (9.5) years and 14.7 (8.6) years. Of the women 163 (69%) were postmenopausal. One hundred and seventeen (50%) women and 28 (54%) men fulfilled the three item criteria. For the diagnosis of osteoporosis (T score <or=-2.5) using the original three item criteria sensitivity in women and men was 74% and 67%, specificity 57% and 50%, PPV 32% and 29% and NPV 89% and 83%, and including weight and ever use of corticosteroids in a five item criteria sensitivity increased to 82% and 83%, specificity decreased to 45% and 45%, PPV was 29% and 31%, and NPV was 90% and 90% respectively.
Conclusion: The novel five item criteria (age, weight, inflammation, immobility, and ever use of corticosteroids) are a more accurate tool to identify patients with RA and osteoporosis than the original three item criteria (age, inflammation, and immobility). The clinical decision rules have an acceptable sensitivity and provide a practical tool for the doctor to identify patients with RA who should have a DXA measurement performed.