Patient selection: gout
Parameters:
(1
) number of attacks during 12 months
(2) serum uric acid in mg/dL
(3) VAS for pain from 0 to 10 cm
(4) VAS for patient global assessment of disease activity (PtGA) from 0 to 10 cm
(5) tender joint count from 0 to 68
(6) swollen joint count from 0 to 66
(7) tophi number
(8) tophi dimension
GAS_3a =
= (0.09 * (attacks)) + (1.03 * SQRT(uric acid)) + (0.16 * (VAS pain)) + (0.17 * (VAS global)) + (0.07 * SQRT(tender joint)) + (0.09 * (SQRT(swollen joint)) + (0.32 * LN(1 + (tophi dimension)))
GAS_1a =
= (0.10 * (attacks)) + (0.27 * (uric acid)) + (0.31 * (VAS pain)) + (0.07 * (VAS global)) + (0.03 * (tender joint)) + (0.01 * (swollen joint)) + (0.09 * (tophi dimension))
GAS_3b =
= (0.08 * (attacks)) + (1.05 * SQRT(uric acid)) + (0.16 * (VAS pain)) + (0.17 * (VAS global)) + (0.07 * SQRT(tender joint)) + (0.08 * SQRT(swollen joint)) + (0.47 * LN(1 + (tophi number)))
GAS_1b =
= (0.10 * (attacks)) + (0.28 * (uric acid)) + (0.31 * (VAS pain)) + (0.07 * (VAS global)) + (0.03 * (tender joint)) + (0.006 * (swollen joint)) + (0.20 * (tophi number))
GAS_3c =
= (0.09 * (attacks)) + (1.01 * SQRT(uric acid)) + (0.34 * (VAS pain)) + (0.53 * LN(1 + (tophi number)))
GAS_1c =
= (0.11 * (attacks)) + (0.25 * (uric acid)) + (0.36 * (VAS global)) + (0.20 * (tophi number))
where:
• The units for tophi dimension are not reported. In Dalbeth et al (2011) tophi dimensions are for subcutaneous nodules only and either diameter in mm or the product of 2 perpendicular diameters in square mm. Presumably the dimensions for all the tophi are added together. This would be the least reproducible parameter. In addition, tophi contain some fibrous tissue which would not respond quickly to a remission.
|
Score
|
Clinical Remission
|
|
GAS_3a
|
< 2.7
|
|
GAS_3b
|
< 2.7
|
|
GAS_3c
|
< 2.5
|
Performance:
• The area under the ROC curves was 0.86.
