Approximately 40% of patients who present with hip complaints, but fail to meet American College of Rheumatology criteria for hip osteoarthritis, developed the condition at 2- to 5-years follow-up, according to recent findings published in Arthritis Research & Therapy.
“We aimed to evaluate the prevalence of hip and knee osteoarthritis according to ACR criteria among participants with suspected early symptomatic OA in the CHECK cohort,” Jurgen Damen, MD, MSc, from Erasmus University Medical Center in the Netherlands, and colleagues wrote. “We also assessed whether participants not fulfilling ACR criteria at baseline develop ACR-defined OA at 2-year and/or 5-year follow up, and which baseline factors are associated with this development.”
The researchers examined data from the CHECK cohort, which included 1,002 individuals who presented with complaints in either the hip or knee. Onset of hip OA or knee OA as assessed by ACR criteria served as the primary endpoint, which Damen and colleagues assessed by clinical classification criteria and a combination of clinical and radiographic classification over a follow-up period of 2 and/or 5 years.
About 40% of patients who present with hip complaints, but fail to meet ACR criteria for hip OA, developed the condition at 2- to 5-years follow-up, according to recent findings.
According to the researchers, of the 588 patients reporting hip complaints at baseline, hip OA according to ACR criteria was observed in 63%. Among the patients who failed to meet criteria for hip OA at baseline, follow-up at 2- and/or 5-years indicated that 40% later developed clinical or combined clinical and radiographic hip OA.
The analysis also included 829 patients reporting knee complaints at baseline. Results showed that 92% of those participants received knee OA classification at that time. For those with knee complaints who were not classified with OA at baseline, 55% developed knee OA during follow-up, according to the findings.
Morning stiffness carried the most significant association with the development of hip OA (OR = 2.39; 95% CI, 1.14-4.98). Other factors associated with this outcome included painful internal rotation (OR = 2.53; 95% CI, 1.23-5.19), hip flexion less than 115 degrees (OR = 2.33; 95% CI, 1.17-4.64) and erythrocyte sedimentation rate (ESR) less than 20 mm/h (OR = 2.94; 95% CI, 1.13-7.61).
The researchers observed no variables that correlated with knee OA over the course of the 2- and/or 5-year follow up, according to the findings. They acknowledged that it was difficult to draw conclusions about individuals with knee complaints because of the small number of patients who developed knee over the course of the study duration.
“We would suggest that future studies validate whether patients with hip complaints aged >45 years with the characteristics of morning stiffness, painful internal rotation, hip flexion <115 degrees and an ESR<20mm/h indeed have early OA,” Damen and colleagues wrote. “It also needs to be validated whether first presenters with knee complaints aged >45 years indeed have early [knee] OA.” – by Rob Volansky
Disclosure: The authors report no relevant financial disclosures.