The review concluded that "these medicines remain a valid treatment option for certain patients with type 2 diabetes" but that "the small increased risk could be reduced by appropriate patient selection and exclusion".
Clinicians are advised to not use pioglitazone in:
- Patients with bladder cancer
- Patients with a history of bladder cancer
- Patients with uninvestigated macroscopic haematuria
Risk factors for bladder cancer should be assessed before starting treatment, especially in older patients and treatment should be regularly reviewed and only continued when treatment continues to provide a benefit.
The relative risk of bladder cancer from three recent observational studies ranges from 1.12 to 1.33. A meta-analysis of randomised controlled trials indicated an absolute risk increase of 0.08% (7 cases in 10,212 patients or 0.07% risk in the placebo group versus 19 cases in 12,506 patients or 0.15% in the treatment group).
The EMA has also requested that a pan-European epidemiological study is conducted to provide more robust information about the risk.
Action: Clinicians should be aware of this review and the additional warnings and contra-indications for pioglitazone. The figures quoted in the review may be helpful when explaining the risks to patients.
UPDATE: A summary is now available from the Medicines and Healthcare products Regulatory Agency (MHRA).