Factors associated with initiation and persistence of urate-lowering therapy.

Background: Gout is the most common inflammatory arthritic disease and is caused by crystal deposition secondary to persistent hyperuricemia. Etiological treatment with urate-lowering therapy (ULT) has been available since the 1950s but previous studies have demonstrated suboptimal degree of treatment. In recent years we have seen recommendations for ULT earlier in the course of the disease, but there are few contemporary reports reflecting the current situation. Therefore we set out to investigate proportion receiving and persisting with ULT after gout diagnosis and predictors thereof.

Method: A population-based cohort study using regional and national population-based registers. Cohort of patients (n = 7709) from western Sweden with incident gout aged 18 years and above from 2011 to 2013. An incident case of gout was defined as having been given a diagnosis of gout (ICD-10 M10, M14.0-14.1) not preceded by a gout diagnosis or a dispensation of ULT during the previous 5 years. Main outcome measures were cumulative incidence and predictors for start of, and persistence with, ULT in gout.

Results: Within the first year after first gout diagnosis, 32% received ULT. Male sex, presence of diabetes or cardiovascular comorbidity, reduced kidney function but not diagnosed "end-stage kidney failure" increased the likelihood of receiving ULT. Of those starting ULT a majority (75%) did not persist with ULT treatment within the first 2 years. Age <50 years, lack of comorbidities, and "normal kidney function" or "end-stage kidney failure" were associated with non-persistence with ULT.

Conclusions: Only a minority of patients received ULT and a majority of these did not persist with treatment over the next 2 years. However, the older patients with renal impairment and comorbidities, possibly suffering from a more severe gout disease, were more likely to receive and persist with treatment. There is thus still room for considerable improvement with regards to management of ULT in gout.