Prevalence of chronic arthritis in four geographical areas of the Scottish Highlands.
A survey of the prevalence of chronic arthritic conditions was carried out on a population of 35,251 patients registered with 29 general practitioners in the highlands of Scotland. Symptomatic osteoarthritis had an overall prevalence of 65 per 1000 but rose from one in 20 of those aged 40-50 years to one quarter of those over 70 years of age. Rheumatoid arthritis was present in 5.5 per 1000 with a two to threefold female preponderance and there was an unexplained threefold difference between the regions with the highest and lowest prevalence. Seronegative arthritides were found in 2.1 per 1000, polymyalgia rheumatica/temporal arteritis in 1.2 per 1000, and gout in 3.4 per 1000. Juvenile chronic arthritis had a prevalence of 0.39 per 1000 (2.0 per 1000 in those aged 15 years and younger) and connective tissue disease 0.45 per 1000. There was considerable variation in the prevalence of inflammatory arthritis throughout the region. The highest prevalence of rheumatoid arthritis was 14.5 per 1000 women in one east coast area and the lowest 5.2 per 1000 women in the west. The difference did not seem to be due to misclassification. A consultant's review of a questionnaire sent to all except those with osteoarthritis changed the proportions of patients who could be confirmed to have the respective inflammatory arthritides (rheumatoid arthritis between 3.4 and 5.0 per 1000, seronegative arthritides 2.0 per 1000, juvenile chronic arthritis 0.52 per 1000), and a third of those diagnosed as having rheumatoid arthritis failed to meet hospital oriented diagnostic criteria.