Clinical Diagnosis of Gout CLINDX
Even if using the prediction rule developed in this study, physicians should consider aspirating most all joints with monoarthritis as value even in joints suggestive of gout had a one in 20 chance of an alternative diagnosis. Also, the label of gout may affect future decision making and life-long medications.
In a study of 381 patients recruited by family physicians because of monoarthritis, 57% had positive crystals and one patient had a bacterial infection.
The family physicians had an accuracy of:
- Sensitivity 97%
- Specificity 28%
The authors then created a prediction rule for the 328 patients that the family physicians suspected had gout:
Male sex 2.0 points
Previous patient-reported arthritis attack 2.0 points
Onset within 1 d 0.5 points
Joint redness 1.0 points
MIP involvement 2.5 points
Hypertension or and cardiovascular diseases 1.5 points
Serum uric acid level >5.88 m9/dL 3.5 points
The prediction rule had an accuracy of:
- 8 or more points
- Sensitivity 92% (193/209)
- Specificity 88% (77/88)
- 4 or less points
- Sensitivity 99% (208/209)
- Specificity 50% (44/88)
If 4 or less points, the NPV is 98%.
If 8 or more points, the PPV=95%.
1. Janssens HJ, Fransen J, van de Lisdonk EH, van Riel PL, van Weel C, & Janssen M (2010). A diagnostic rule for acute gouty arthritis in primary care without joint fluid analysis. Archives of Internal Medicine, 170 (13), 1120-6 PMID: 20625017