Evaluation of health care costs and utilization patterns for patients with gout.

BACKGROUND: The prevalence of gout has been increasing. Serum uric acid (sUA) levels ≥6 mg/dL have been associated with high morbidity and increased health care utilization.

OBJECTIVE: To assess the costs and patterns of health care resource utilization for patients with gout, categorized into 3 cohorts based on sUA levels.

METHODS: We retrospectively analyzed laboratory, pharmacy, and medical service claims data (January 2005 to June 2010) for patients ≥18 years old. Inclusion criteria were at least 2 sUA levels and at least 1 primary gout diagnosis (International Classification of Disease-9th revision code 274.xx), and/or at least 1 prescription for gout-specific medications. Outcomes including costs, health care resource utilization, and medication adherence and persistence were assessed for the 1-year postindex period and summarized for the 3 cohorts based on sUA levels: <6 mg/dL, 6 to 8.99 mg/dL, and ≥9 mg/dL. Costs were adjusted based on preindex utilization and baseline characteristics.

RESULTS: Three hundred fifty-two patients met the inclusion criteria: cohort 1 (sUA <6 mg/dL), n = 38, mean age 59 years; cohort 2 (sUA 6-8.99 mg/dL), n = 231, mean age 61 years; and cohort 3 (sUA ≥9 mg/dL), n = 83, mean age 62 years. Mean adjusted gout-related health care costs were $332, $353, and $663, respectively (P <0.05); mean adjusted all-cause health care costs were $11,365, $11,551, and $14,474, respectively, for the 3 cohorts (P <0.05). sUA levels were positively associated with the percent of patients who had at least 1 hospitalization and the mean number of hospitalizations and emergency department visits (P < 0.05). Significantly more patients with sUA <6 mg/dL achieved adherence rates of ≥80% and had a longer mean duration of continuous treatment compared with patients with sUA between 6 and 8.99 mg/dL or ≥9.0 mg/dL (P <0.05).

CONCLUSIONS: Patients with high levels of sUA had higher gout-related and all-cause health care costs, more all-cause hospitalizations, and emergency department visits, but they also exhibited poorer adherence and persistence.