Validity of American College of Rheumatology criteria for diagnosing hip osteoarthritis in primary care research

Objective, To study the validity of the American College of Rheumatology (A CR) criteria for hip osteoarthritis (OA) in patients receiving primary care . Three different sets of criteria are available, one with clinical symptom s only, and 2 with clinical symptoms and radiological signs combined. it is claimed that all 3 sets, separate from each other, can be used to diagnose hip OA for research purposes, Methods. Consecutive patients (n = 227) aged 50 years or older, who had con sulted a general practitioner for pain in the hip and had been referred for radiographic investigation of the hip. were recruited for a standardized h istory taking and physical investigation. The radiographs were evaluated ac cording to a standardized protocol. The cross validity of the 3 different s ets of ACR criteria was assessed by calculating the percentage agreement an d the kappa between the separate sets. Results. There was poor agreement between the set of clinical criteria and the 2 sets in which radiological signs were included (kappa 0.11 or lower). The 2 sets th;it included radiological signs showed high agreement (kappa 0.81-0.94, depending on cut off points fur joint space narrowing), These se ts also showed the highest agreement with the radiological OA defined as a Kellgren score 2 or more (kappa 0.13-0.48). Conclusion. The clinical ACR criteria showed no cross validity with the 2 o ther ACR criteria sets.