Effectiveness and side effects of thiazolidinediones for type 2 diabetes: real-life experience from a tertiary hospital

Objective: To assess effectiveness and side effects of thiazolidinediones (TZDs) as adjunctive therapy in suboptimally controlled patients with type 2 diabetes. Design and setting: Review of a prospectively recorded database at the Royal Melbourne Hospital diabetes clinic. Participants: 203 patients with type 2 diabetes who received pioglitazone or rosiglitazone between 1 May 2000 and 31 October 2002. Outcome measures: Response in glycohaemoglobin (HbA(1c)) level, lipid profile changes and side effects, including hypoglycaemia, weight gain, oedema and precipitation of cardiac failure. Results: Both pioglitazone and rosiglitazone improved glycaemic control, with a reduction in the HbA(1c) level of 1.02% (range, 0.85%-1.19%) and 0.96% (range, 0.81%-1.11%), respectively, in the first 6 months of therapy. Rosiglitazone was associated with a 0.45 mmol (range, 0.31-0.59 mmol) increase in cholesterol level and 0.99 mmol (range, 0.60-1.38 mmol) increase in triglyceride level, while pioglitazone was associated with insignificant declines in cholesterol and triglyceride levels. There was reduced requirement for insulin, but not for oral hypoglycaemic agent (OHA), in most patients who used these agents. Pioglitazone and rosiglitazone were associated with increased rates of hypoglycaemia (17% and 11% of patients, respectively), significant weight gain (48% and 58%) and oedema (33% and 21%). There were four cases of acute left ventricular failure and two cases of reversible liver dysfunction in patients treated with TZDs. Conclusions: Adding pioglitazone or rosiglitazone therapy to OHA or insulin inpatients with type 2 diabetes significantly improved glycaemic control. However, the use of these drugs in routine clinical practice was associated with more frequent adverse events than previously reported in clinical trials.