Introduction: Despite its relative high prevalence,potential devastating clinical consequences and socio-economic impact, the existence of effective drugs to treat it, and the well recognised direct relation between acute flares and treatment interruptions and its resumption, gout is still often considered the chronic disease with the worst rate of adherence to therapy. The reason for this is unknown. We proposed to thoroughly evaluate a subgroup of patients, aiming at identifying the clinical features predictive of non-compliance, and 5 different ways to assess those.
Methods: We analysed a number of clinical, analytical and ultrasound data relating to 34 gout patients (according to the Wallace-ARA diagnostic criteria for gout 1977 and the EULAR recommendations for gout diagnosis 2006), which were followed in a specialized rheumatology consultation as part of an ongoing study for ultrasound validation in gout. To assess non-compliance, we compared the prevalence of each one of these clinical features with 5 outcomes (2 of which related to "non-compliance": self-report of non-adherence to therapy and missing consultation, and 3 other outcomes related to "non-response": gout flare(s), final serum uric acid (sUA) ≥ 6 mg/dL, and no sonographic improvement) registered during a 1 year of follow-up assessment.
Results: We have found an association between younger age, higher body mass index, previous treatment with urate lowering drugs, self-report of previous non-compliance, nephrolithiasis and hyperuricosuria and the "outcomes of non-compliance". These patients tended to be less often treated with NSAID and allopurinol, and more often treated with corticosteroid and benzbromarone during the 1 year follow-up. They have also presented higher rate of gout flares and final sUA. Evaluating the 3 "outcomes of non-response", we have noticed a tendency for association with long disease duration, self-report of previous non-compliance (frequently attributed to gout flare), higher initial sUA and kidney failure. These patients tended to be less often treated with NSAID, and more often treated with allopurinol. Gout flare correlated to self-report of non-compliance and no sonographic improvement. Sonographic non response also correlated to higher final sUA.
Conclusions: This study shows an association between some clinical features and non-compliance, but above all, and unlike the majority of other studies, it has found a correlation between non-compliance with possible causes of worst response or lower rate of treatment, such as hyperuricosuria, nephrolithiasis, kidney failure, and contraindication for NSAID treatment. The data which is based on a comprehensive and detailed clinical assessment, might point out hidden elements, which might go beyond the visible non-compliance, contributing to the frequent lack of control of the disease.