Clinical presentation of osteoarthritis in general practice: Determinants of pain in Italian patients in the AMICA study

OBJECTIVE To assess the clinical characteristics and determinants of pain observed by general practitioners (GPs) in Italian patients with osteoarthritis (OA) of the hand, hip, and knee. METHODS The 2764 GPs participating in the study were asked to enroll 10 consecutive patients with OA diagnosed according to the American College of Rheumatology (ACR) clinical criteria. To standardize the diagnosis, the GPs received ad hoc training from musculoskeletal system specialists. A questionnaire evaluating demographic data, the clinical characteristics of OA, and previous diagnostic and therapeutic interventions was administered by the GPs. RESULTS 25,589 evaluable patients were enrolled during a mean period of 2.8 weeks by the GPs: 17,567 women (69%) and 7878 men (31 %). The most painful OA joints were the knee in 12,827 patients (54%), the hip in 5645 patients (24%), and the hand in 5467 patients (23%)percentages calculated on the 23,939 patients for whom this information was available. The weekly incidence of referrals to GPs for OA was higher for women and for knee OA. The median age of the patients was 70 years (range 50 to 104 years) and disease duration was 8.3 +/- 7.10 years. The most frequent comorbidities were hypertension (53%), obesity (22%), osteoporosis (21 %), type II diabetes mellitus (15%), and chronic obstructive pulmonary disease (13%). The median pain visual analog scale (VAS) score was higher for women than for men, for hip OA, and for generalized OA (GOA) than for knee and hand OA (P < 0.0001). Intense pain, defined as VAS readings of > 60 mm, was increased in women only in the knee (OR = 1.24; 95% Cl 1.15 to 1.34) and in GOA (OR = 1.17; 95% Cl 1.03 to 1.33). It was also significantly increased in patients older than 70 years (OR = 1.46; 95% Cl 1.39 to 1.54), those with a low educational level (OR = 1.44; 95% Cl 1.36 to 1.5), a BMI of 2:30 (OR = 1.52; 95% Cl 1.42 to 1.61), a disease duration of more than 7 years (OR 1.60; 95% Cl 1.52 to 1.68), comorbidities (OR = 1.61; 95% Cl 1.5 to 1.73), and GOA (OR 2.05; 95% Cl 1.91 to 2.19). Manual occupations were associated with highly intense pain only in men. CONCLUSIONS The results of this study underscore the major impact of OA on care in general practice, the high frequency of OA-associated comorbidities, and the role of different risk factors in OA pain.