Background/Purpose

Gout is the most common inflammatory arthritis in the US. For most patients, excruciatingly painful gout attacks (“flares”) are the major clinical burden of the disease. The goal of this study was to assess the association of flare frequency with economic outcomes including all-cause and gout-related health care costs to better understand the economic benefit of reducing flare frequency.

Methods

This cohort study used administrative claims data from a large US health plan of commercially insured and Medicare Advantage enrollees. Patients were identified based on medical and pharmacy claims for gout between January 2009 and April 2012. The 12 months prior to the index gout claim was used to assess baseline confounders. Gout flares were assessed in the 12 months following the index gout claim based on diagnoses for gout or joint pain followed within 7 days by claims for NSAIDs, colchicine, corticosteroids, or joint aspiration/drainage. Flare frequency, gout treatments, and all-cause and gout-related health care costs were assessed in the 12 months following the index gout claim. Patient characteristics and economic outcomes were compared between patients with infrequent flares (0-1 flares in the 12-month follow-up period) to those with 2 flares or ≥3 flares. Generalized linear models were used to adjust for potential confounders.  

Results

Our study included 102,703 patients; 89,201 had 0-1 flares, 9714 had 2 flares, and 3788 had ≥3 flares. Demographic and baseline characteristics did not appear to be meaningfully different among these groups (Table). After adjusting for potential confounders, patients with 2 or ≥3 flares had significantly higher mean all-cause and gout-related total health care costs compared to those with 0-1 flares. Adjusted all-cause costs were $11,786, $12,625, and $15,328 in those with 0-1, 2, and ≥3 gout flares, respectively (p=0.012 comparing 0-1 flares to 2 flares; p<0.001 comparing 0-1 flares to ≥3 flares). Adjusted gout-related costs were $1,804, $3,014, and $4,363, in those with 0-1, 2, and ≥3 gout flares, respectively (p<0.001 comparing 0-1 flares to 2 or ≥3 flares).

Conclusion

The economic implications of frequent gout flares are significant, particularly when comparing patients with infrequent flares (0-1 flares per year) to those with 2 or ≥3 flares. Gout-related costs were 67% higher in those with 2 flares and nearly 150% higher in those with ≥3 flares compared to those with infrequent flares. This suggests significant cost benefit to a disease management plan with a goal of reducing flare frequency to fewer than 2 per year. Future research should consider costs beyond those related to health care utilization and include costs from other sources such as missed work and loss of worker productivity.   

Table. Demographics and Baseline Patient Characteristics by Flare Frequency