Reply to Ribera Montés et al

Reply to Ribera Montés et al. Sir—We have read with interest the letter of Ribera Montés et al. [1]. In response to the authors' comments on our article [2], we note that, in contrast with recent observations [3] (but not with older studies [4]), the frequency of asymptomatic bacteriuria (ASB) was similar in women with and without diabetes, as was found in our study. In addition, a significantly higher mean level of glycosyilated hemoglobin (HbA1c) was demonstrated in women with type 2 diabetes who had ASB, compared with women with diabetes who did not have ASB [2]. With regard to the HbA1c confidence interval, the differences between the groups mean values and upper, and lower confidence intervals (P < .05) were 0.7, 1.4, and 0.005, respectively. The authors of the letter [1] reported a prevalence of ASB of 25.6% in their cohort of women with type 2 diabetes using the criterion of 2 consecutive positive urine culture results. This rate of ASB is much higher than that reported in other studies that used the same criterion in defining ASB [5] and is higher than the rate observed in our study [2], in which a single positive result of a urine culture of a clean-voided midstrem urine sample was used. This difference could be explained by hypothesizing additional risk factors for ASB in the population in the study by Ribera Montés' et al. [1]—for example, how many women with indwelling bladder catheter or recent vesical catheterization were included in their study? Regarding the metabolic control of disease in the women with diabetes in our study, we state that ∼50% of our patients had HbA1c values of ⩽8.5%. In 1997, when we started the study, an HbA1c value of 7%–8.5% had been suggested as the ideal realistic therapeutic window [6]. The method we used for HbA1c assay was high-performance liquid chromatography (HPLC); the authors of the letter [1] have not indicated whether they used the same method or an immunological method. Some discrepancies have been reported in the HbA1c assay using immunological and HPLC methods [7]. In addition, we note that recently, according to the American Diabetic Association [8], a preprandial plasma glucose level of 90–130 mg/dL has been recommended. These values are slightly lower than those found in our diabetic women. Furthermore, in our study [2], microalbuminuria and an increased plasma fibrinogen level (a well-known marker of inflammation) were not demonstrated as risk factors for ASB. Pyuria did occur at a similar rate in bacteriuric women with and without diabetes. We confirm that, in our cohort of 176 women with type 2 diabetes, there was a significant association between an increase in the HbA1c level and the risk of developing ASB. We agree with Ribera Montés et al. [1] that it is difficult to compare the results of different reported studies, because patients included in the studies may be very heterogeneous. For this reason, studies are in progress in our laboratory to identify further risk factors for ASB, in addition to the role played by the degree of metabolic control of diabetes.