The burden of musculoskeletal diseases in the general population of Spain:results from a national survey

Objective-The objective of the EPISER study was to estimate the prevalence of rheumatoid arthritis (RA), low back pain, hand and knee osteoarthritis ( OA), and fibromyalgia in the adult Spanish population, and to assess the im pact of these diseases on function and quality of life, and use of health a nd social resources. Methods-2998 subjects aged 20 years or above were randomly selected by stra tified multistage cluster sampling from the censuses of 20 municipalities. Trained rheumatologists carried out structured visits at which subjects wer e asked about rheumatic symptoms and sociodemographic characteristics, comp leted validated instruments for measuring function (HAQ) and quality of fif e (SF-12), and underwent a standardised physical examination. Cases were de fined by previously validated criteria. Results-The estimated prevalences with 95% confidence intervals were as fol lows: RA lifetime cumulative: 0.5% (0.3 to 0.9); low back pain: 14.8% (12.2 to 17.4); symptomatic knee OA: 10.2% (8.5 to 11.9); hand OA: 6.2% (5.9 to 6.5); fibromyalgia: 2.4% (1.5 to 3.2). Most conditions significantly impair ed function and quality of life. Conclusions-The EPISER study has internal and external validity for applica tion of the results to the adult Spanish population. The diseases studied a ffect a significant proportion of the population, with various degrees of i mpact on disability and quality of life resulting in a significant number o f physician visits, work disability, and medication use.