A bibliometric study of the scientific publications on patient-reported outcomes in rheumatology.

Introduction: We have conducted a bibliometric study of the scientific publications on patient-reported outcomes in the field of rheumatology.

Methods: SCOPUS was the database used in this bibliometric study. We performed two searches. The main search involved selecting the documents published between 2000 and 2014 limited to top-tier journals addressing rheumatic and musculoskeletal diseases, using specific descriptors together with the operator and main descriptor "patient-reported outcomes" (PROs), and we performed a secondary search, with the following specific descriptors: "pain," "functional capacity," and "fatigue." We used bibliometric indicators for articles distribution (Price's law for the increase of scientific literature and Bradford's law for dispersion of articles). We also calculated the participation index of the different countries.

Results: A total of 983 original articles were published between 2000 and 2014. Our results confirmed the fulfilment of Price's law (correlation coefficient r = 0.9385 after linear adjustment). The average number of articles per Bradford Zone was 327.6. A total of 30 different journals were published. The type of growth for the descriptors "pain" (r = 0.5417 compared to r = 0.4839) and "fatigue" (r = 06276 compared to r = 0.5544) is exponential, whereas it is linear for the descriptor "functional capacity" (r = 0.6769 compared to r = 0.3779).

Discussion: This study revealed significant linear growth of patient-related outcomes in global terms, as well as upward trends for most of the citation-based bibliometric indices, especially significant from 2010 to 2014. Pain and fatigue have greater growth as PRO concepts.