TOPLINE:

In a population-based cohort of patients newly diagnosed with bladder cancer, post-diagnostic hyperglycaemia was associated with a higher risk for bladder cancer-specific and overall mortality than normoglycaemia.

METHODOLOGY:

• Researchers in Finland conducted a population-based cohort study to assess the relationship between diabetes and prognosis in 14,638 patients newly diagnosed with bladder cancer during 1995-2012 (median age at diagnosis, 73 years; 76.2% men).
• Data on fasting blood glucose levels were available for 624 participants, with 143 having diabetes.
• Hyperglycaemia was determined using blood glucose levels or A1c measurements, and the role of antidiabetic medication was also assessed.
• The median follow-up duration was 4.3 years after the diagnosis of bladder cancer.

TAKEAWAY:

• Post-diagnostic blood glucose levels in the diabetic range were associated with higher bladder cancer-specific mortality (hazard ratio [HR], 1.58; 95% CI, 1.10-2.28) and overall mortality (HR, 1.50; 95% CI, 1.20-1.89) than normoglycaemia, after adjustment for confounders.
• The risk for mortality was lower among patients with hyperglycaemia using antidiabetic medication (HR, 1.43; 95% CI, 0.68-3.02) than among those not using that medication (HR, 1.80; 95% CI, 1.13-2.85) but remained higher than that among those with normoglycaemia in both groups.
• Higher post-diagnostic A1c levels were linked to higher overall mortality (HR, 1.43; 95% CI, 1.06-1.93).
• Among participants who had normoglycaemia before diagnosis, post-diagnostic blood glucose levels in the diabetic range strongly predicted overall mortality (HR, 2.63; 95% CI, 1.47-4.70).

IN PRACTICE:

"This indirectly supports hyperglycemia as supporting cancer progression, whereas antidiabetic medication use may mitigate the risk increase. However, both predicted overall mortality equally, suggesting that diabetes in general is a risk factor, presumably due to cardiovascular effects," the authors wrote.

SOURCE:

This study was led by Lauri Vuoristo, University of Tampere, Tampere, Finland. It was published online on December 12, 2025, in PLOS One.

LIMITATIONS:

Information on tobacco smoking was insufficient. Blood glucose and A1c results were available only for a subset of patients. The registry recorded tumour extent only as local or metastatic, without details on muscle invasion or carcinoma in situ. This study could not analyse type 1 and 2 diabetes separately.

DISCLOSURES:

This study did not receive any specific funding. Some authors reported receiving consultant fees, lecture fees, or research funding from several pharmaceutical companies.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.