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    Changes in the clinical profile of gout patients over the last 25 years

    Background: The number of publications associated to gout, as well as the prevalence of the disease, has increased in recent years. Gout is a rising cause of hospital admissions and emergency consults. More so in patients with comorbidities, it has even replaced rheumatoid arthritis as the principal rheumatological condition causing admissions (1). Some questions arise in this setting: What are the characteristics of our patients? How have they changed over the past years?

    Objectives: To analyze possible changes in the epidemiologic, clinical and biochemical profiles of gout patients during a period of 25 years.

    Methods: Data was collected from a prospective cohort of gout patients, from a crystal arthritis clinic in a tertiary hospital, with a reference population of half a million inhabitants. A period of 25 years was reviewed, between 1992 and 2016 (n = 1137), with further division into five quinquennia (Q) for comparison purposes. When entering the cohort, epidemiologic, clinic, laboratory and imaging data are systematically collected. Variables susceptible to change in time were considered: age, gender, gout specific clinical data (articular pattern, presence of tophi), previous admissions due to gout, comorbidities and association with other conditions. Quantitative variables were analyzed with ANOVA and Bonferroni correction; qualitative variables with chi-square test. Inclusion of patients to the cohort was approved by the hospital ethics committee. Results from extreme quinquennia are reported (1stQ: 1992-1996 / 5thQ 2011-2016 or 2ndQ: 1997-2001 / 4th: 2006-2010). All results are statistically significant unless stated otherwise.

    Results: Differences were observed amongst the periods of five years and age at first visit (1stQ: 54.1 ± 10.9 / 5thQ: 64.6 ± 13.8 years); gender (1stQ: 2.6% / 5thQ: 12.2% of women, respectively). There were no differences when comparing with years of disease evolution before the first visit. Initial comorbidities: important differences pertaining the prevalence of cardiovascular disease were observed (2ndQ: 26.3% / 5thQ: 43.2%), as well as renal disease (1stQ: 16.7% / 5thQ: 45.2%), hypertension (1stQ: 27.3% / 5thQ: 75.1%) and hyperlipidaemia (1stQ: 50.6% / 5thQ: 61.2%) –although this was not the case for Diabetes Mellitus. There was difference amongst periods and association with acute episodes of calcium pyrophosphate arthritis (1stQ: 3.8% / 5thQ: 5.9%). Initial clinical characteristics: differences were found in presentation with tophi (2ndQ: 23.6% / 4thQ: 40.1%); polyarticular disease (1stQ: 32.9% / 5thQ: 41.3%); hospital admission on the year prior to inclusion (1stQ: 14.5% / 5thQ: 24.4%); use of diuretics (1stQ: 6.4% / 5thQ: 45.9%); and uricaemia, the latter with no relevant clinical significance.

    Conclusions: The profile of gout patients has notably changed in the past 25 years: we have elder, more complex patients, with higher rates of hospital admissions, with severe forms of disease and important comorbidities. When considering these results, we believe that a substantial proportion of gout patients will require specialized attention in the coming years.

    References: (1) Lim SY, Lu N, Oza A, et al. Trends in Gout and Rheumatoid Arthritis Hospitalizations in the United States, 1993-2011. JAMA. 2016 Jun 7;315(21):2345-7.