Background Allopurinol (ALP) and febuxostat (FBX) are indicated for the treatment of hyperuricemia due to gout. Scant real-world research has compared the economic outcomes of these agents in renally compromised patients.
Objectives To compare utilization and expenditure in patients with both gout and CKD after initiating therapy with FBX and ALP.
Methods Gout patients (ICD-9-CM 274.xx), aged >18, were selected from the MarketScan® databases (January 2008-December 2012) if they had evidence of CKD, stages 3-4 (ICD-9-CM 585.3 or 585.4), prior to initiating with either ALP or FBX and also met continuous enrollment criteria. Mean monthly expenditure (2012 US$) overall, gout specific (for anti-gout agents or claims with a primary gout diagnosis), and non-gout specific (all other claims) expenditures were examined during initial exposure to either agent. General linear models (gamma distribution and log-link function) were used to identify factors which significantly impacted healthcare expenditures.
Results Among the 3,570 study eligible patients, 2,442 and 1,128 initiated on ALP and FBX respectively. Mean (SD) follow-up was 9.3 (3.8) months in the FBX cohort and 9.4 (3.8) months in the ALP cohort. At index, 74.1% of patients had stage 3 CKD and 21.4% had stage 4 disease. Comorbidities included hypertension (66% of the cohort), DM (41.1%). ischemic heart disease (29.2%), dyslipidemia (26.3%), HF (22.3%), OA (15.7%), and COPD (11.6%). Overall, both cohorts were equally comorbid, each with a mean (SD) Charlson Comorbidity Index of 3.9 (1.9). FBX patients had significantly higher flare rates during baseline (p<0.0001) and were significantly (p<0.001) more likely to have been exposed to colchicine, glucocorticoids or probenecid.
Mean (SD) monthly cost per patient overall was $2,145 ($3,963) with 44% of total cost provided in the outpatient setting $941 ($1,843); 33% of cost provided in the inpatient setting $707 ($3,009) and 24% in the outpatient pharmacy setting $497 ($538). Thirty-five percent of patients had ≥1 emergency room visit. While gout specific expenditure per month was significantly (p<0.0001) higher in the FBX cohort ($225 vs. $65), total cost per patient per month was similar between the cohorts ($ 2,205 vs. 2,118) due to significantly (p<0.05) lower rates of non-gout specific hospitalization (4.7% vs. 6.5%) and lower outpatient medical cost ($842 vs. $935). Higher gout specific cost in the FBX cohort was driven almost entirely by the higher cost associated with gout agents ($179 vs. $22). Factors associated with significantly (p<0.05) higher total cost in MV models include potential markers of baseline gout severity (exposure to glucocorticoids, NSAIDs), coexisting heart failure or diabetes and resource intensity at baseline. The decision to treat with either ALP or FBX did not have a significant impact on total cost (p=0.2).
Conclusions Patients with concurrent gout and CKD are clinically complex and were found to be resource intensive in all care settings in this study. Mean total healthcare costs were similar between groups, and mean total gout-related healthcare cost was significantly greater in patients taking FBX vs ALP. These data suggest that the higher initial cost for treatment with FBX should not be a barrier to appropriate treatment and that the choice of agent should not be based on their cost alone.
Disclosure of Interest None declared