[Prevalence of ten Immune-mediated inflammatory diseases (IMID) in Spain]

Immune-mediated inflammatory diseases (IMID) are chronic and highly disabling diseases that share inflammatory sequences and immunological dysregulations. Considered as a disease in itself, the prevalence of IMID is virtually unknown. The aim of this study was to assess the prevalence of 10 selected UDI, including rheumatoid arthritis, psoriasis, psoriatic arthritis, ankylosing spondylitis, ulcerative colitis, Crohn's disease, systemic lupus erythematosus, hidradenitis suppurativa, sarcoidosis and uveitis in Spain.

cross-sectional epidemiological study of point prevalence was made. This study was carried out through a series of computerized interviews in households chosen at random in 17 autonomous communities in Spain. A structured questionnaire was used to determine the frequency of diagnosis and the concurrence of 10 IMID in the respondents and other individuals belonging to the same family nucleus. The point prevalence estimates were used and compared with the objective of determining the frequency of IMID by age, sex and communities. The data were processed using Excel 2016 (Microsoft, Redmond, WA, USA) and the SPSS V.019 system (IBM Corp. Armonk, NY, USA) for statistical analysis using the usual statistical tests in this type of studies.

Of the 7,980 respondents, 510 were diagnosed with an IMID, representing a cross-sectional study of 6.39% (95% CI: 6.02-6.76). One, two, three or more members of the family were affected in 87.2%, 7.8% and 5% of positive relatives in IMID, respectively. The most recurrent diseases were psoriasis (2.69% [95% CI: 2.32-3.06]) and rheumatic arthritis (1.07% [95% CI: 0.70-1.44]). There were differences in prevalence due to sex (p = 0.004) and age (p = 0.000). No significant differences were identified related to geographic location (p = 0.819). Attendance of at least 2 IMID was reported in 8.9% of respondents.

The overall prevalence was of the IMID studied was 6.39%, psoriasis being the most frequent with 2.69%. This study constitutes an initial step to consider IMID as an independent disease within the health system..