Objective: Previous research has suggested that peroxisome proliferator-activated receptor-gamma (PPAR-γ) may play an important role in immunomodulation. We examined whether PPAR-γ agonists (thiazolidinediones) were associated with the incidence of bacterial abscess among patients with type 2 diabetes.

Research Design and Methods: This retrospective cohort study included 46,986 propensity-matched patients diagnosed with type 2 diabetes between 2000 and 2010. We compared the incidence of bacterial abscess and the incidences of two subclasses: liver and non-liver abscesses, between groups treated with either metformin plus a thiazolidinedione (M+T, N=7831) or metformin plus a sulfonylurea (M+S, N=39,155). Data were retrieved from a population-based Taiwanese database. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) with Cox proportional hazard regression models.

Results: During a median follow-up of 4.5 years, the adjusted rate of incident bacterial abscess was lower with M+T than with M+S treatment (1.89 vs. 3.15 per 1000 person-years). M+T was associated with a reduced risk of bacterial abscess (adjusted HRs: 0.58, 95% CI: 0.42-0.80 for bacterial abscess; 0.54, 95% CI: 0.28-1.07 for liver abscess; and 0.59, 95% CI: 0.41-0.85 for non-liver abscess). The results did not change materially, after accounting for unmeasured confounding factors and differential censoring between the two treatment groups. Rosiglitazone and pioglitazone, in combination with metformin, produced similar reductions in risk for all abscess outcomes.

Conclusions: We found that M+T had a substantial protective effect in reducing the incidence of bacterial abscesses. These findings merit further investigation.


C. Chang: None. J. Wang: None. Y. Dong: None. W. Ko: None. L. Wu: None. L. Chuang: None. P. Chen: None.

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