The prevalence of osteoarthritis in rural Egypt: a WHO-ILAR COPCORD study

Abstract

Objective: Osteoarthritis (OA) is the commonest form of arthritis affecting every population and ethnic group. The prevalence of OA and its types however varies in different studies according to the population studied, the denominator age of the population and the criteria used to define OA, whether clinical or radiological or both. This study was carried out to investigate the prevalence of OA and its types in a rural area of Egypt as part of a large study examining the prevalence of rheumatic diseases in Egypt. Methods: The study was conducted in Makosa village of Al-Minia governorate in Southern Egypt in 4 phases. Of the whole adult population (15 years and above) comprising 5208 individuals, 88 (1.7%) declined to participate in the study and 5120 subjects (98.7%, 2562 female and 2558 male) were screened by a preliminary WHO-ILAR-COPCORD questionnaire inquiring about joint and bone pain, swelling, stiffness or tenderness in the last 7 days. Those who answered positively were administered a more detailed questionnaire and invited for examination and laboratory and radiological investigations as required. A rheumatologist administered the 2 questionnaires face-to-face and carried out examinations to ensure reliability and validity of data collection. Consequently, OA cases were diagnosed according to validated criteria (1986 clinical ACR criteria for OA of the knee, 1986 ACR criteria for OA of the hand and 1991 ACR criteria for OA of the hip). Results: OA was the commonest rheumatic disease in the population, with OA cases constituting more than half of patients with rheumatic diseases, whether female (53.2%), male (50.8%) or total (52.4%). Osteoarthritis was diagnosed in 434 individuals, with a prevalence of 8.5% in the total adult population (95% CI: 7.7–9.1%). The prevalence of OA was significantly higher in females (10.9%) than males (6.1%) (p < 0.001). Local OA was the commonest type of OA diagnosed (6.3%), while the prevalence of primary generalized OA (nodal and non-nodal) was 1.5%, and secondary OA was found in 0.6% of the population. Regardless of type, the knee was afflicted in the majority of cases, with knee OA diagnosed in 8.1% of the population, while the prevalence of hand OA was 1.5%. Hip OA was rare, being diagnosed in only 3 cases (0.06%). Conclusion: OA is the commonest rheumatic disease in Egypt, with a prevalence of 8.5%. The disease is more common in females than males and predominantly affects the knees, while hip OA is extremely rare