Diabetes appears to have an adverse effect on complications and outcomes of chemotherapy in older women with breast cancer, according to Houston-based researchers.

"We found that diabetic patients with breast cancer have higher rates of chemotherapy-related toxicities," Dr. Sharon H. Giordano told Reuters Health.

Using a Medicare database, Giordano, of The University of Texas M. D. Anderson Cancer Center, and colleagues identified more than 71,000 patients aged 66 and older with breast cancer.

Almost 12,000 were treated with chemotherapy and 21 percent of these patients were diabetic. Those with diabetes, the researchers found, were more likely to be hospitalized because of chemotherapy-related toxicity, infection, fever, a drop in infection-fighting white blood cells, and anemia.

Diabetic breast cancer patients were also 32 percent more likely to be hospitalized for any reason and were 35 percent more likely to die than nondiabetic women.

In patients who did not receive chemotherapy, breast cancer-related death rates were similar in diabetics and nondiabetics. However, in the chemotherapy cohort, it was greater in diabetics.

"Despite these findings," the researchers conclude, "patients with diabetes should continue to be offered standard chemotherapy regimens, because this study cannot definitely answer which chemotherapy offers the best risk-benefit ratio for patients with diabetes."

Giordano urges doctors to "be aware that diabetic patients are more likely to experience toxicity and...monitor diabetic patients closely."