CRITERIA FOR GENERALIZED AND FOCAL OSTEOARTHRITIS

Study objective: to identify homogeneous, distinct subgroups of osteoa rthritis patients based on distribution of osteoarthritis lesions. Pat ients-Methods. Study design: cross-sectional, prospective, multicenter . Patients with osteoarthritis of the hip, knee, fingers, or spine. Da ta collected: clinical and radiologic features at 41 joint sites. Meth ods: multivariate statistical analysis including a) k-mean clustering analysis followed by ascending hierarchical classification b) and a tr ee-structured discriminant method to confirm and to characterize the s ubgroups obtained using the clustering method. Results. The 1021 patie nts were first classified into five categories with an error rate (obt ained by cross-validation) of 7.6%. The tree obtained by segmentation took into account manifestations of osteoarthritis at the hands, knees and spine. Irrespective of the reason for seeking medical advice, pat ients with bilateral involvement of the fingers or with involvement of the spine and both femorotibial joints were classified as having gene ralized osteoarthritis; in contrast, focal osteoarthritis was defined as the absence of involvement of the fingers and of either the spine o r the knees. Conclusion. The statistical analysis provided a classific ation system that would be easy to use in everyday clinical practice. Prospective studies are needed to evaluate the potential clinical rele vance of this system.