Hypouricemic effect of metformin in gout patients with type 2 diabetes

Abstract

Treatment of gout and type 2 diabetes mellitus (T2DM) is strategically similar: with gout, the goal is to achieve a normal serum urine acid (SUA) level (< 360 μmol/L), with T2DM — normalization of glycemia, a frequent combination of these metabolic diseases requires taking into account the effect of drug therapy on concomitant diseases. As compared to the current drugs used in gout treatment, metformin (Met) has the potential advantage of targeting multiple aspects of the disease. The study aims to investigate the effect of Meton SUA levels in gout patients with T2DM. Materials and methods. A retrospective analysis of medical records was carried out on 208 gout patients with Т2DM ≥ 18 years with at least one year of follow-up treatment in the rheumatology department. The survey was divided into 2 groups: Met group (n = 107) — gout patients received Met (1000–2500 mg/daily) and control group (n = 101) — gout patients received other peroral hypoglycemic therapy. Results. Analysis of the baseline parameters in the groups of gout patients showed that Met users were somewhat younger (60 (58.72 ± 9.73) and 61 (60.9 ± 9.4), respectively) (P < 0.02) and had better renal function ((Me 60 [50–70] and 50 [44–66], respectively) (P < 0,005) compared to non-Met users. The vast majority of patients in both groups had more than two joints affected (79.4 and 83.2 %, respectively). The drug of the choice to start urate-lowering therapy in most cases was allopurinol (98.1 and 98.0 %, respectively). After one year, gout patients in the Met group showed a significant decrease in SUA levels from (468.9 ± 61.9) to (318.7 ± 44.9) μmol/L (P < 0.0001). Within one year, 63.6 % of the Met group had reached target SUA levels compared to 47.5 % in the control group (P < 0.023). The achievement of a significant decrease in fasting blood IRI (from 28.1 [12.8; 49.2] to 19.1 [11.5; 45.8] μmol/L (P < 0.01), the HOMA-IR (from 3.5 [1.7; 9.1] to 2.8 [1.4; 9.2] (P < 0.01) in patients Met group. The mean incidence of gout attacks was 2.02 per year (95 % CI (1.28–2.36)) in the Met group and 4.00 per year (95% CI (2.56–5.42)) in the control group (P < 0.01). The mean daily dosages of allopurinol at target for the Met group and control group did not differ significantly and amounted to (258 ± 120) and (246 ± 110) mg, respectively. Conclusions: The use of a combination of metformin plus urate-lowering therapy (allopurinol) in gout patients with type 2 diabetes mellitus allows to achieve the target of serum urine acid level in 64 % of patients; helps to reduce the severity of insulin resistance and significantly associated with a lower incidence of gout attacks.