Urinary tract infection in patients with diabetes mellitus

Diabetes, SGLT-2 Inhibitors, and Urinary Tract Infection: a Review

PURPOSE OF REVIEW

The aim of this review is to focus on epidemiology, pathogenesis, risk factors, management, and complications of UTI in people with diabetes as well as reviewing the association of SGLT-2 inhibitors with genitourinary infections.

RECENT FINDINGS

Individuals diagnosed with T2DM are more prone to experiencing UTIs and recurrent UTIs compared to individuals without T2DM. T2DM is associated with an increased risk of any genitourinary infections (GUI), urinary tract infections (UTIs), and genital infections (GIs) across all age categories. SGLT2 inhibitors are a relatively new class of anti-hyperglycemic agents, and studies suggest that they are associated with an increased risk of genitourinary infections. The management of diabetes and lifestyle modifications with a patient-centric approach are the most recognized methods for preventing critical long-term complications including genitourinary manifestations of diabetes. The available data regarding the association of SGLT-2 inhibitors with genitourinary infections is more comprehensive compared to that with UTIs. Further research is needed to better understand the mechanisms underlining the association between SGLT-2 inhibitors and genital infections and UTIs.

Urinary tract infections: a review of the current diagnostics landscape

Urinary tract infections are the most common bacterial infections worldwide. Infections can range from mild, recurrent (rUTI) to complicated (cUTIs), and are predominantly caused by uropathogenic Escherichia coli (UPEC). Antibiotic therapy is important to tackle infection; however, with the continued emergence of antibiotic resistance there is an urgent need to monitor the use of effective antibiotics through better stewardship measures. Currently, clinical diagnosis of UTIs relies on empiric methods supported by laboratory testing including cellular analysis (of both human and bacterial cells), dipstick analysis and phenotypic culture. Therefore, development of novel, sensitive and specific diagnostics is an important means to rationalise antibiotic therapy in patients. This review discusses the current diagnostic landscape and highlights promising novel diagnostic technologies in development that could aid in treatment and management of antibiotic-resistant UTIs.

Impact of Diabetes on Complications, Long Term Mortality and Recurrence in 608,890 Hospitalised Patients with Stroke

Background:

Patients with diabetes mellitus (DM) have been found to be at an increased risk of suffering a stroke. However, research on the impact of DM on stroke outcomes is limited.

Objectives:

We aimed to examine the influence of DM on outcomes in ischaemic (IS) and haemorrhagic stroke (HS) patients.

Methods:

We included 608,890 consecutive stroke patients from the Thailand national insurance registry. In-hospital mortality, sepsis, pneumonia, acute kidney injury (AKI), urinary tract infection (UTI) and cardiovascular events were evaluated using logistic regressions. Long-term analysis was performed on first-stroke patients with a determined pathology (n = 398,663) using Royston-Parmar models. Median follow-ups were 4.21 and 4.78 years for IS and HS, respectively. All analyses were stratified by stroke sub-type.

Results:

Mean age (SD) was 64.3 (13.7) years, 44.9% were female with 61% IS, 28% HS and 11% undetermined strokes. DM was associated with in-hospital death, pneumonia, sepsis, AKI and cardiovascular events (odds ratios ranging from 1.13–1.78, p < 0.01) in both stroke types. In IS, DM was associated with long-term mortality and recurrence throughout the follow-up: HR_max (99% CI) at t = 4108 days: 1.54 (1.27, 1.86) and HR (99% CI) = 1.27(1.23,1.32), respectively. In HS, HR_max (t = 4108 days) for long-term mortality was 2.10 (1.87, 2.37), significant after day 14 post-discharge. HR_max (t = 455) for long-term recurrence of HS was 1.29 (1.09, 1.53), significant after day 116 post-discharge.

Conclusions:

Regardless of stroke type, DM was associated with in-hospital death and complications, long-term mortality and stroke recurrence.

Polymersome–hydrogel composites with combined quick and long-term antibacterial activities

Intrinsically antibacterial polymersomes loaded with antibiotics were incorporated into hydrogels, exhibiting quick and long-acting antibacterial activity.

Proinsulin Shares a Motif with Interleukin-1α (IL-1α) and Induces Inflammatory Cytokine via Interleukin-1 Receptor 1

Although it has been established that diabetes increases susceptibility to infections, the role of insulin (INS) in the immune response is unknown. Here, we investigated the immunological function of INS. Proinsulin dimer (pINSd) was a potent immune stimulus that induced inflammatory cytokines, but mature INS was unable to induce an immune response. An affinity-purified rabbit polyclonal antibody raised against mature IL-1α recognized IL-1α and pINS but failed to detect mature INS and IL-1β. Analysis of the pINS sequence revealed the existence of an INS/IL-1α motif in the C-peptide of pINS. Surprisingly, the INS/IL-1α motif was recognized by monoclonal antibody raised against IL-1α. Deleting the INS/IL-1α motif in pINSd and IL-1α changed their activities. To investigate the pINSd receptor, the reconstitution of IL-1 receptor 1 (IL-1R1) in Wish cells restored pINSd activity that was reversed by an IL-1R antagonist. These data suggested that pINSd needs IL-1R1 for inflammatory cytokine induction. Mouse embryo fibroblast cells of IL-1R1-deficient mice further confirmed that pINSd promotes immune responses through IL-1R1.

The association between obesity and urinary tract infection

BACKGROUND

Few studies examined the relationship between obesity and urinary tract infection (UTI), showing inconsistent results. This study aims to examine the association between obesity and UTI, and to assess whether this association is independent of diabetes mellitus and 25(OH)D level.

METHODS

Using the computerized database of the largest healthcare provider in Israel, we identified a cohort of subjects ≥18years old with available BMI and serum 25(OH)D level measurements between January 2009 and December 2009. The cohort was followed for the first UTI diagnosis from January 2010 through June 2011. Cox proportional hazard model was used to test the relationship between obesity and UTI.

RESULTS

During follow-up, 25,145/110,736 (22.7%) females, and 4032/42,703 (9.4%) males had UTI. The crude HR for UTI in those with BMI≥50 compared to BMI<25 was 2.54 (95% CI, 1.50-4.30) in males and 1.39 (1.14-1.69) in females. After adjusting for age, 25(OH)D level, and history of diabetes mellitus, the HR for UTI in those with BMI≥50 compared to BMI<25 was 2.38 (1.40-4.03) in males and 1.25 (1.03-1.52) in females. The HR for those in the lowest quartile of serum 25(OH)D compared to the highest quartile was 1.23 (1.13-1.35) in males and 0.98 (0.95-1.02) in females. The HR for subjects with diabetes was 1.23 (1.16-1.32) in males, and 1.25 (1.20-1.28) in females.

CONCLUSIONS

Obesity is independently associated with UTI particularly in males. Low serum 25(OH)D levels are associated with increased risk of UTI in males.

Increased risk of urinary tract calculi among patients with diabetes mellitus--a population-based cohort study

OBJECTIVE

To investigate the inter-relationship among diabetes, urinary tract infection (UTI), and urinary tract calculi (UTC).

METHODS

This study used Taiwan's National Health Insurance claims data of ambulatory care visits and hospitalizations. A total of 12,257 newly diagnosed diabetes cases in 2000-2002 and 96,781 controls were followed to the end of 2007. The person-year approach with Poisson assumption was used to estimate the incidence density (ID) of UTC by diabetic status. Relative risk of UTC in relation to diabetes and UTI were estimated from Cox proportional hazard model with adjustment for sociodemographic variables and comorbidities.

RESULTS

Over nearly 8 years of follow-up, 8.9% of diabetes and 7.2% of control subjects sought ambulatory care or were hospitalized for UTC, representing the ID of 14.4 and 11.4 per 1000 person-years, respectively. The multivariate analysis indicated that UTC risk was independently associated with diabetes (hazard ratio 1.18, 95% CI 1.10-1.27) and UTI (HR 1.68, 95% CI 1.60-1.76). The hazard ratio of UTC in relation to diabetes in men and women without UTI was 1.24 and 1.26, respectively. Diabetes may further increase the rate of UTC in women with UTI, with an hazard ratio increased from 1.79-2.12. Such additive effect by diabetes in men with UTI was only marginal (HR 1.68 vs 1.67).

CONCLUSION

This cohort study provides epidemiologic support for the causal association between diabetes and UTC, which is independent of UTI. In addition, female patients with UTI accompanied by diabetes tended to be associated with a greater rate of UTC.

Incidence of renal and perinephric abscess in diabetic patients: a population-based national study

This population-based cohort study aimed to investigate the incidence and relative hazard of renal and perinephric abscess (RA) in the diabetic population in Taiwan. More than a half million diabetic patients and sex- and age-matched controls were identified from the 1997 Taiwan National Health Insurance data and were linked to in-patient claims from 1997 to 2007. Person-year approach with Poisson assumption was used to estimate the incidence density (ID) of RA. The hazard ratios (HRs) of hospitalization due to RA in relation to diabetes were analysed using a Cox proportional hazard model. The ID for the diabetic and control subjects was 4·6 and 1·1/10,000 person-years, respectively, in 11 years of follow-up, representing an adjusted HR of 3·81 (95% confidence interval 3·44-4·23). This study confirmed the association of diabetes with RA, and argued that more aggressive urological care should be administered to diabetic patients.

[Risk factors for the development and persistence of asymptomatic bacteriuria in patients with type 2 diabetes]

BACKGROUND AND OBJECTIVE

To study the risk factors for the development and persistence of asymptomatic bacteriuria (AB) in type 2 diabetes mellitus (DM) patients from our health zone.

PATIENTS AND METHOD

Observational and laboratory prospective cohort study.

INCLUSION CRITERIA

women and men with type 2 DM from the 2 health centers of Petrer (Alicante).

DATA

questionnaire including particular and epidemiological data. Laboratory values: biochemistry, glycosylated hemoglobin A1C, microalbuminuria, urinary sediment and urine culture.

RESULTS

A total of 457 patients with type 2 DM were included; 63.2% women and 36.8% men. The prevalence of AB at baseline was 19.9% (25.6% in women vs 10.1% in men). 78.02% had persistence of AB after the twelve months of follow-up; 21.7% developed symptomatic urinary tract infection (UTI) and 35.2% were treated with antimicrobial agents for any reason different from UTI during the follow-up period. The persistence of AB at the end of the study was 15.5%. Female sex (p = 0.04), leukocyturia (p = 0.008), urinary incontinence (p = 0.04) and elevated C reactive protein concentration (p = 0.009) remained significant risk factors for the presence and the persistence of AB when the multivariate logistical regression analysis was done. The presence of UTI within one year before the study started (p= 0.024) and previous antibiotic treatments (p = 0.04) were also independent significant factors associated with persistent AB. 84.5% of diabetic patients with persistent AB had the same infective organism in the urine culture as those found during the initial AB.

CONCLUSIONS

In patients with type 2 diabetes, female sex, urinary incontinence, leukocyturia, and elevated C reactive protein concentration were associated with development of AB. The same occurred with obesity in women and prostatic syndrome in men. The persistence of AB with the same species of isolated microorganisms as those found in AB at study entry is frequent, but it remains to be known if eradication of pathogens is more difficult in diabetic patients or, alternatively, if AB episodes are transient.

Pathogenesis of bacteriuria in women with diabetes mellitus

Women with diabetes mellitus (DM) have asymptomatic bacteriuria (ASB) and symptomatic urinary tract infections (UTIs) more often than women without DM. The increased prevalence of bacteriuria in diabetic patients can be the result of differences in the host responses between diabetic and nondiabetic patients, or a difference in the infecting bacterium itself. We have shown that the increased prevalence of ASB in diabetic women is not the result of a difference in bacteria, because the same number of virulence factors was found in the infecting Escherichia coli (most common causative microorganism of ASB) in our diabetic women with ASB, as listed in the literature for nondiabetic patients with ASB. We found that bacterial growth in vitro was increased after the addition of different glucose concentrations, as found in urine of poorly controlled patients. However, we could not confirm that glucosuria was a risk factor for ASB in vivo. In addition, we demonstrated that women with both DM and ASB have lower urinary cytokine and leukocyte concentrations than women without DM but with ASB. Finally, we found that E. coli expressing type 1 fimbriae (the virulence factor that plays an important role in the pathogenesis of UTIs) adhere better to uroepithelial cells of women with DM compared with the cells of women without DM.

Urinary tract infections in adults with diabetes

Urinary tract (UTI) is a major disease burden for many patients with diabetes. Asymptomatic bacteriuria is several-fold more common among women and acute plyelonephritis is five to ten times more common in both sexes. The complications of pyelonephritis are also more common in patients with diabetes. These complications include acute papillary necrosis, emphysematous pyelonephritis, and bacteremia with metastatic localization to other sites. The management of urinary infection in patients with diabetes is essentially the same as patients without diabetes. Most infections should be managed as uncomplicated except when they occur in a milieu with obstruction or other factors that merit a diagnosis of complicated UTI. Strategies to prevent these infections and reduce morbidity should be a priority for research.

Cytokine secretion is impaired in women with diabetes mellitus

BACKGROUND

As women with diabetes mellitus (DM) have an increased prevalence of asymptomatic bacteriuria (ASB) and it is known that a correlation exists between the increased prevalence of genitourinary tract infection and impaired cytokine production in women infected with Human Immunodeficiency Virus (HIV), we studied urinary cytokine excretion in diabetic women and compared it with that of nondiabetic controls.

MATERIALS AND METHODS

To evaluate the cytokine secretion capacity of women with DM, both whole blood and isolated monocytes of women with and without DM were stimulated in vitro with lipopolysaccharide (LPS).

RESULTS

Lower urinary interleukin-8 (IL-8) and interleukin-6 (IL-6) concentrations (P = 0.1 and P < 0.001, respectively) were found in diabetic women than in nondiabetic controls. A lower urinary leukocyte cell count correlated with lower urinary IL-8 and IL-6 concentrations (P < 0.05). Lower tumour necrosis factor-alpha (TNF-alpha) and IL-6, but comparable interleukin-10 (IL-10) concentrations were found in whole blood (P < 0.04) and isolated monocytes (P = 0.03) of women with DM type 1 compared to women without DM.

CONCLUSIONS

Diabetic women with ASB have lower urinary IL-6 concentrations than nondiabetic bacteriuric controls. In addition, monocytes of women with DM type 1 secrete lower pro-inflammatory cytokines after stimulation with LPS than monocytes of women without DM. This is not due to an inhibitory effect of the anti-inflammatory cytokine IL-10. This can have important consequences for both host defense, endothelial cell functioning and atherogenesis.

Leukocyturia in women with diabetes and its clinical implications

BACKGROUND

Urinalysis is one of the most common studies performed on the diabetic patient at every visit. The presence of leukocyturia is relatively common but it is not clear what the attitude of the physician toward this particular finding should be. The main objective of the present study was to investigate the clinical significance of leukocyturia in diabetic women.

METHODS

Ninety-eight diabetic women (84.7% type 2) aged 57 +/- 13 years who were being seen at the diabetic out-patient clinic were randomly selected. All patients underwent a clinical and gynecologic examination and a urinalysis. A Papanicolaou smear and a urine culture were also obtained.

RESULTS

The overall prevalence of leukocyturia (>5 cells/high power field (hpf)) was 46.5%. Patients with urinary tract infections (UTI) were 7.5 times more likely to have leukocyturia, while a leukocyte count <5cells/hpf predicted the absence of UTI in 96% of the women. In the comparison of patients with and without leukocyturia, we found that proteinuria (p = 0.06) and bacteriuria (p <0.002) were more common in the women with leukocyturia. A significant association with leukorrhea was not demonstrated. The empirical use of antibiotics was 12 times more frequent in the patients with leukocyturia.

CONCLUSIONS

A urinary culture should be requested in all diabetic patients with leukocyturia. The possibility of a UTI is remote when leukocyturia is absent.