Meiland R et al. (2006) Asymptomatic bacteriuria in women with diabetes mellitus. Arch Intern Med 166: 2222–2227

Previous studies in women with diabetes mellitus suggested that greater declines in renal function occurred over 18 months in those who had asymptomatic bacteriuria, compared with those who did not. These results suggested a potential link between urinary-tract infection and diabetic nephropathy. Meiland and colleagues carried out a large, prospective study to investigate this link, but they found no association between asymptomatic bacteriuria and accelerated renal decline after 6 years of follow-up.

Their study prospectively evaluated 296 women with type 1 and 348 women with type 2 diabetes mellitus, who were followed up for 1.0–8.3 years (mean 6.1 years). At baseline, 50% of the cohort had hypertension. Asymptomatic bacteriuria was diagnosed in 17% of the cohort—that is, in those whose first urine sample collected was positive for micro-organisms (predominantly Escherichia coli) in the absence of fever or symptoms suggestive of urinary-tract infection. Irrespective of whether they had type 1 or type 2 diabetes mellitus, the women with asymptomatic bacteriuria had a steeper decline in creatinine clearance and lower absolute creatinine clearance values at the study end, and were more likely to have hypertension, than patients without asymptomatic bacteriuria; however, these differences were mainly explained by the effects of patient age and duration of diabetes, and were absent on multivariate analysis.

The authors conclude that screening for and treatment of asymptomatic bacteriuria (in women with diabetes) is unjustified, because it is unlikely to reduce the incidence of diabetic nephropathy.