[ArtRoCad: health resources utilization and socioeconomic impact of knee and hip osteoarthritis. I. Methods and population characteristics].

OBJECTIVE The ArtRoCad study analyzes healthcare resource utilization and the socioeconomic impact of knee and hip osteoarthritis in primary care in Spain. The present study describes the methodology of the ArtRoCad study and presents the main characteristics of the population included. METHODS We performed a cross-sectional study of ambulatory patients in primary care, aged ≥ 50 years old, with a diagnosis of knee or hip osteoarthritis and a history of pain for 3 months in the previous year. The patients were selected consecutively on a country-wide basis, proportional to the general population aged ≥ 50 years. The most important localization for healthcare demand was considered the main affected joint. The study was performed in October and November, 2003. Information on clinical data, quality of life and resource consumption, sick leave from work or days of disability in the previous 6 months were gathered through 2 structured interviews. RESULTS Eighty-seven percent of the physicians predicted by sampling participated in the study, accounting for 82% of the predetermined sample size. A total of 1,071 patients were interviewed. The distribution of the main affected joint was as follows: knee 710 (66.3%), hip 252 (23.5%) and both knee and hip 109 (10.2%). Seventy-five percent of the sample was aged 65 years or older and 74% were women. Most of the patients had moderate or severe osteoarthritis with a median pain duration of between 6 and 10 years. More than half the patients experienced additional limitations due to musculoskeletal problems other than knee and/or hip osteoarthritis. CONCLUSIONS Participation in the ArtRoCad study was excellent. The sample obtained was representative of the population with symptomatic moderate or severe osteoarthritis of the knee and hip in primary care, with substantial comorbidity.