Evaluation of the Sensitivity and Specificity of the New Clinical Diagnostic and Classification Criteria for Kashin-Beck Disease, an Endemic Osteoarthritis, in China

This study aimed to evaluate the sensitivity and specificity of the new clinical diagnostic and classification criteria for Kashin-Beck disease (KBD) using six clinical markers: flexion of the distal part of fingers, deformed fingers, enlarged finger joints, shortened fingers, squat down, and dwarfism. One-third of the total population in Linyou County was sampled by stratified random sampling. The survey included baseline characteristics and clinical diagnoses, and the sensitivity and specificity of the new criteria was evaluated. We identified 3,459 KBD patients, of which 69 had early stage KBD, 1,952 had stage I, 1,132 had stage II, and 306 had stage III. A screening test classified enlarged finger joints as stage I KBD, with a sensitivity and specificity of 0.978 and 0.045, respectively. Shortened fingers were classified as stage II KBD, with a sensitivity and specificity of 0.969 and 0.844, respectively, and dwarfism was classified as stage III KBD with a sensitivity and specificity of 0.951 and 0.992, respectively. Serial screening test revealed that the new clinical classification of KBD classified stages I, II, and III KBD with sensitivities of 0.949, 0.945, and 0.925 and specificities of 0.967, 0.970, and 0.993, respectively. The screening tests revealed that enlarged finger joints, shortened fingers, and dwarfism were appropriate markers for the clinical diagnosis and classification of KBD with high sensitivity and specificity.