Diabetes and the course of febrile urinary tract infection.

Diabetes is considered a risk factor for acquisition of febrile urinary tract infection (UTI) (1,2), but there is a lack of information on the association of diabetes with the subsequent course of disease and its outcome. We performed a prospective observational multicenter cohort study including consecutive adults with community-onset febrile UTI presenting at 7 emergency departments and 35 primary care centers. The effect of preexisting diabetes on presentation and microbiological and clinical outcome was assessed and multivariable logistic regression performed to establish whether diabetes was an independent risk factor for a complicated course.

Of 858 patients, 140 had diabetes (93% type 2 diabetes), of whom 41 (30%) used insulin, 19 (14%) were managed by diet only, and the remaining were managed by a combination of metformin, insulin, and diet. Patients with diabetes were older (median age 73 years [interquartile range {IQR} 46–78] vs. 64 [IQR 42–77], P < 0.001), were more frequently male (48 vs. 35%, P = 0.006), and had a higher rate of cardiovascular and urinary tract comorbidities (28 vs. 12%, P < 0.001, and 34 vs. 23%, P = 0.005). Clinical symptoms did not differ between diabetic and nondiabetic patients (Table 1), except that diabetic patients less frequently experienced flank pain, as reported previously (3). Escherichia coli was the most common isolated uropathogen in both diabetic and nondiabetic patients. Diabetes was not associated with a longer duration of fever (median 2 days in both groups) or prolonged hospital admission (both median 6 days). Patients with diabetes more often had bacteremia at presentation (30 vs. 22%, P = 0.037), intensive care unit admission (6 vs. 3%, P = 0.065), recurrent UTI (9 vs. 3%, P = 0.017), asymptomatic bacteriuria (13 vs. 9%, P = 0.247), and mortality during 30 days of follow-up (6 vs. 2%, P = 0.007). However, when adjusted for possible confounders such as underlying cardiovascular disease, diabetes was not an independent risk factor for any of these complications—bacteremia odds ratio (OR) 1.2 (95% CI 0.8–1.8), 30-day mortality OR 2.0 (0.7–5.8), recurrent UTI OR 2.2 (95% CI 0.7–6.8), and asymptomatic bacteriuria after 1 month OR 1.1 (0.5–2.5)—although women with diabetes were at increased risk of asymptomatic bacteriuria after 1 month (15 vs. 4%, P = 0.003, OR 4.3 [95% CI 1.5–11.9]). The higher prevalence of complications in patients with diabetes was mainly explained by an increased prevalence of cardiovascular comorbidity and higher age.

Table 1

Baseline characteristics of 858 patients presenting with febrile UTI

Although it is widely held that patients with diabetes more often have a complicated course of infections, our prospective multicentre cohort study shows that diabetes is not independently associated with a complicated course in an unselected population of patients with febrile UTI. The prevalence of complications was higher in diabetic patients but attributable to concurrent illnesses, especially cardiovascular comorbidities, and a higher age of the diabetic population. Our study does not lend support for an increased duration of antimicrobial treatment of febrile UTI in diabetic compared with nondiabetic patients, since clinical and microbiological outcomes after 1 month did not differ significantly between both groups and diabetic and nondiabetic patients were treated alike.