The IRIS V study: pioglitazone improves systemic chronic inflammation in patients with type 2 diabetes under daily routine conditions.

BACKGROUND

The peroxisome proliferator-activated receptor-gamma agonist pioglitazone is established as a drug to treat patients with type 2 diabetes mellitus. In addition to lowering blood glucose levels, one of the favorable effects of pioglitazone is improvement of systemic chronic inflammation particularly affecting vessel walls. The effect can be monitored by the measurement of the biomarker C-reactive protein in the range of 0-10 mg/L (high-sensitivity C-reactive protein [hsCRP]). This observational trial was performed to evaluate the effects of pioglitazone on hsCRP values in a large population under daily life conditions.

METHODS

A total of 1,170 subjects could be included into the final analysis (633 men, 537 women; age [mean +/- SD], 63.5 +/- 10.4 years, body mass index, 31.0 +/- 5.5 kg/m2; duration of diabetes, 6.9 +/- 8.1 years; glycosylated hemoglobin [HbA1c], 7.5 +/- 1.1%). All patients were glitazone-naive prior to study entry. The patients received pioglitazone alone or in combination with their previous treatment (acarbose, sulfonylurea drugs, and/or metformin). Patients were evaluated at baseline and after 10 +/- 2 weeks and 20 +/- 2 weeks of treatment. Observation parameters were fasting blood glucose, lipids, and blood pressure. The level of hsCRP was determined in a central laboratory at baseline and at end point.

RESULTS

All markers showed a significant improvement at trial end point. A decrease of hsCRP (baseline 3.3 +/- 1.0 mg/L vs. end point 2.8 +/- 2.3 mg/L, P < 0.01), HbA1c (7.5 +/- 1.1% vs. 6.8 +/- 0.9%, P < 0.001), fasting blood glucose (8.7 +/- 2.6 mM vs. 7.2 +/- 2.1 mM, P < 0.001), low-density lipoproteins (3.3 +/- 1.0 mM vs. 3.2 +/- 0.9 mM, P < 0.001), and triglycerides (2.4 +/- 2.0 mM vs. 2.2 +/- 2.5 mM, P < 0.001) and an increase in high-density lipoproteins (1.3 +/- 0.4 mM vs. 1.4 +/- 0.4 mM, P < 0.001) was observed. Parallel to the metabolic improvement, both systolic and diastolic blood pressure values were reduced (141 +/- 17 mm Hg vs. 137 +/- 15 mm Hg and 83 +/- 9 mm Hg vs. 80 +/- 9 mm Hg, respectively; P < 0.001 in both cases).

CONCLUSIONS

These observational results, obtained from a nonselected patient population under daily routine conditions, confirm the benefits of pioglitazone treatment on blood glucose, lipid metabolism, and blood pressure. The results show that pioglitazone treatment improves chronic vascular inflammation, which may be associated with reduced cardiovascular risk.