Severity of hand osteoarthritis and its association with upper extremity impairment in a population of disabled older women: The Women's Health and Aging Study

Most severity indices of osteoarthritis (OA) include measures of physical f unction which render them unsuitable for assessing the impact of OA on disa bility. Data from 1002 moderate to severely disabled community-dwelling wom en greater than or equal to 65 years were used to develop hand OA severity indices which are independent of functional status. Baseline exams and stre ngth tests were conducted by trained nurse examiners. Each distal and proxi mal interphalangeal joint, and first carpometacarpal joint (20 joints in al l) was scored for the presence of a) bony enlargement or deformity, and b) pain on motion or tenderness on palpation. Severity indices were then creat ed. Deformity index (DEF) = sum of joints with bony changes (0-20); Pain/Te nderness index (PT) = sum of joints with pain or tenderness (0-20); and Com bined Deformity/Pain index = sum of DEF and PT (0-40). These indices were t hen validated against grip and pinch strength. All three indices showed a s ignificant trend for weaker grip strength as severity index scores increase d. When the 25(th), 50(th) and 75(th) percentiles were used to divide each severity index into levels Of involvement, a threshold effect was observed with significantly poorer grip strength performance above the 75(th) percen tile for each index. Similar results were seen for pinch strength. In concl usion, these hand OA severity indices, based on examination findings alone, help distinguish disease status, and may provide a valuable research tool for investigating the role of hand OA in impairment and disability. (C) 199 9, Editrice Kurtis.