Researchers are theorizing that diabetics may have weaker immune systems
CHICAGO—Diabetes increases the likelihood of UTI recurrences in pre- and post-menopausal women, despite longer treatments with more potent initial antibiotics, a Dutch study shows.
Investigators in The Netherlands compared current UTI treatment strategies in women with and without diabetes. Pre-menopausal women with type 1 or 2 diabetes more often received a longer treatment with norfloxacin, but had a higher recurrence rate compared with those women without diabetes. The same held true for post-menopausal women.
“We still need prospective trials to confirm this, but we theorize that diabetics may have weaker immune systems,” said investigator Suzanne Geerlings, MD, PhD, an infectious diseases specialist at the Academic Medical Centre in Amsterdam. “Some studies have shown that patients with diabetes mellitus have lower local cytokine secretion in the urinary tract. So, this correlates to the number of leukocytes in the urinary tract, and if the cytokines are lower, there are also a lower number of leukocytes. This, of course, is the most important first-line host defense,” she said.
Dr. Geerlings, who presented the study findings here at the 47th Interscience Conference on Antimicrobial Agents and Chemotherapy, said these findings suggest that diabetic patients may need to have a different treatment strategy for UTIs than for non-diabetics.
She and her colleagues obtained data from PHARMO (www.pharmo.com), a Dutch national registration database with pharmacy dispensing data. A total of 10,366 women with type 1 or 2 diabetes (18% premenopausal, age 55 and younger) were compared with 200,258 women without diabetes (68% pre-menopausal). All women in both groups received a first course of trimethoprim, nitrofurantoin, fosfomycin, or norfloxacin between January 1999 and January 2006.
The investigators compared short treatment (one to five days) with long treatment (more than five days) and compared norfloxacin (an agent with high tissue penetration) with trimethoprim, nitrofurantoin, and fosfomycin (agents with low tissue penetration). The researchers defined UTI recurrence as a second prescription for these agents or a first with amoxicillin-clavulanic acid, fluoroquinolones, or trimethoprim/sulfamethoxazole (TMP/SMX) between 6 and 30 days. All analyses were adjusted for age variance.
Among pre-menopausal women, 26.5% of type 2 diabetics received longer treatment compared with 19.2% of nondiabetics. More diabetics than nondiabetics were treated with norfloxacin (10.7% vs. 6.2%). Diabetics, however, had higher recurrence rates (16.1% vs. 12.2%). Nevertheless, hospitalization rates for UTI complications were statistically similar between the two groups (0.1% versus 0.1%).
For post-menopausal women, more type 2 diabetics than nondiabetics received longer treatment (32.8% vs. 28.8%). Diabetics were more frequently treated with norfloxacin (15.2% vs. 12.7%), but they had a higher recurrence rate (19.1% vs. 16.4%). In this group, hospitalization frequency for UTI complications was slightly higher for diabetics (0.3% versus 0.2%).
When all analyses were repeated after exclusion of women who were taking other medications for GI, skin, respiratory, ear and eye problems at the time of antibiotic prescription, these findings were still maintained.
“Our data support [the view] that women with diabetes must be treated for longer periods of time with more potent initial antibiotics,” Dr. Geerlings said.