PPAR-γ agonist pioglitazone and the risks of malignancy among type2 diabetes mellitus patients.

Aims: PPAR-gamma shows promise in inhibiting malignancy cell progression. However, pioglitazone, the sole current PPAR-gamma agonist, was reported to have risks of bladder cancer in previous clinical researches. This study is aimed to assess the influence of pioglitazone on the development of tumors.

Methods: By using Taiwan's National Health Insurance Research Database, this nested case-control study identified incident type2 diabetes initiating metformin treatment between 2000 and 2014, and then categorized into two groups based on whether they developed malignancies after enrollment or not. The index date was defined as the date of malignancy diagnosis in the cancer group or a matched date in the non-cancer group. We analyzed the exposure to pioglitazone preceding the index date.

Results: 47,931 patients in the cancer group and 47,931 patients in the matched non-cancer group were included. The non-cancer group exhibited a significantly higher rate of pioglitazone prescription before the index date for overall malignancies (odds ratios for pioglitazone use were 0.91, 0.92, 0.94, and 0.93 in the first, second, third, and fourth years before the index date). For breast cancer and prostate cancer, pioglitazone was frequently prescribed in the non-cancer group, whereas for pancreatic cancer, pioglitazone use was more common in the cancer group.

Conclusions: PPAR-gamma agonists may be associated with reduced risks of overall malignancies, particularly for breast and prostate cancers. However, it may be linked to an elevated risk of pancreatic cancer.