Keywords
Urinary Tract Infection, Metformin, SGLT-2 inhibitors, diabetes mellitus.
Many antidiabetic medications with distinct modes of action are available, The sodium glucose cotransporter-2 (SGLT-2) inhibitors are among the most recent oral antihyperglycemic medications. The American Diabetes Association recommends metformin, a biguanide medication, as the first option for oral control of type 2 diabetes because it has demonstrated promise in this regard.
To evaluate and compare the effects of metformin and SGLT-2 inhibitors on general urine parameters in T2DM patients from Iraq.
a prospective cohort study where 101 adult patients of both sexes aged under 70 years and newly diagnosed with T2DM, patients were divided into two groups, Metformin group (n=52), where metformin was prescribed as monotherapy by the clinician and SGLT-2 inhibitors group (n=49) where either dapagliflozin or empagliflozin were prescribed by the clinician, general urine examination was done for each patient in the first contact and after 12 weeks of treatment.
The mean age was 57±9 years for the metformin group and 54±9 years for the SGLT-2 inhibitors group. There was no significant difference in leukocytes, erythrocytes, or epithelial cell counts between the metformin group and the SGLT2 inhibitor group before and after 12 weeks of treatment. There was a significant difference (p-value =0.043) in leukocytes and a non-significant difference in erythrocytes and epithelial cell counts before and after treatment in the SGLT-2 inhibitors group.
Diabetic patients on SGLT-2 inhibitors treatment demonstrated higher leukocyte count than metformin group patients, an indicator and predictor for higher susceptibility to urinary tract infections.
Urinary Tract Infection, Metformin, SGLT-2 inhibitors, diabetes mellitus.
Diabetes mellitus type 2 (T2DM) is linked to a high rate of death and morbidity, and it may harm the patient’s cardiovascular, renal, and neurological systems.1 One of the main risk factors for type 2 diabetes is a family history of the disease. It is characterized by gradual dysfunction of β-cells; numerous studies have employed C peptide levels as a biomarker of β-cell function.2 Patients with coronary artery disease have more health issues as a result of insulin resistance, which is the primary cause of type 2 diabetes.3 Diabetes mellitus type 2 frequently results in diabetic nephropathy. Urine and plasma contain neutrophil gelatinase-associated lipocalin (NGAL), which is detectable beginning two to four hours following a kidney injury. When GFR decreased, serum NGAL rose noticeably. Regarding type 2 diabetes mellitus, serum NGAL may be a prognostic sign for the early identification of diabetic nephropathy.4 In the general population, diabetes mellitus type II (DM) is one of the main causes of osteoporosis.5 Longer diabetes duration was associated with a higher risk of UTI rather than glycemic control (HbA1C). Women receiving pharmaceutical treatment for diabetes were primarily at higher risk, indicating a correlation between the severity of diabetes and UTI risk. The most frequently isolated organism in all women, including young women, was E. coli.6 Among female diabetics with problems of neuropathy, nephropathy, and retinopathy, the prevalence of asymptomatic pyuria has increased. As diabetic microangiopathy worsens, the prevalence of asymptomatic pyuria rises with the increasing period of having diabetes.7 Medication and lifestyle modifications are two methods for treating type 2 diabetes. The American Diabetes Association8 recommends that the biguanide medication metformin be used as the primary option for oral therapy of type 2 diabetes because it has demonstrated promise. Weight loss, vascular protection, and glucose metabolism are all positively impacted by metformin.9 Patients with type 2 diabetes (T2DM) may have considerable differences in their glycemic control and adiposity indicators due to a variety of factors, including metformin dosages and treatment adherence. Elevating the metformin dose did not correlate with body fat percentage or insulin resistance.10 Dapagliflozin is a popular oral antidiabetic medication that selectively and reversibly inhibits the sodium-glucose co-transporter-2 (SGLT-2). It increases urine glucose excretion, which can dramatically reduce hyperglycemia without affecting the function of the pancreatic β cell. Compared to the control group, dapagliflozin improves hemoglobin concentration and corrects anemia in patients with heart failure and CKD.11 SGLT-2 inhibitors provide bacteria with a substrate to feed on since they increase the amount of glucose in the urinary system. As a result, they have already been connected to genitourinary tract infections.12 The current study aims to evaluate and compare the effects of metformin and SGLT-2 inhibitors on general urine parameters in T2DM patients from Iraq.
In a prospective study where 101 adult patients of both sexes aged under 70 years and newly diagnosed with T2DM based on the International Expert Committee criteria,13 patients were recruited and called weekly from a single private clinician record who gave informed consent to access the weekly patient archives for 2 months. The recruited patients were then divided into two groups: the Metformin group (n=52), where metformin was prescribed as monotherapy by the clinician, and the SGLT-2 inhibitors group (n=49) where either dapagliflozin or empagliflozin were prescribed by the clinician, Each patient was invited to a private laboratory where sociodemographic data (age, education level, social status, and smoking status) and clinical data were collected during the face-to-face interviews with the patients. A microscopic general urine examination was then done for each patient on their first contact and after 12 weeks of treatment.
The study was conducted in cooperation with a single private internist clinic and a single private laboratory in Baghdad, Iraq. The patients were recruited and did their first general urine examination in the period between the 1st of January 2023 and the 1st of March 2023, All patients underwent their second test before the 1st of May 2023, and all patients and other private parties provided their written and informed consent to participate in the study.
Inclusion criteria
Adult Patients of both sexes aged under 70 years old, newly diagnosed with T2DM,13 taking either metformin monotherapy or SGLT-2 inhibitors (Dapagliflozin or Empagliflozin).
Exclusion criteria
Patients who refused to participate in the study, patients with ongoing acute or chronic kidney diseases, and patients with ongoing urinary tract infections.
Each patient was provided 15-30 ml of clean-catch midstream urine, the urine specimen was then prepared and examined under the High Power Field of the light microscope (Olympus BX51 Microscope, Olympus Corporation®, Japan) to count the cells and provide the result of cellular microscopic examination.
Each patient underwent two microscopic general urine examinations separated by 12 weeks of continuous diabetes treatment, data on the Erythrocyte count, Leukocyte count, and epithelial cell count was then obtained in the Cell/HPF unit to evaluate and compare the effect of both metformin and SGLT-2 inhibitors on these urinary parameters.
Each eligible patient completed the research tool in writing and completed the consent form. The following formula was utilized to determine the sample size14:
In this case, d indicates the precision of the quantitative variable estimate, n is the sample size, α is the first type, Z is the table-based normal distribution index that is taken into account at 5% type-one error (P<0.05), and σ stands for the small variable variance.15 A first type error in this study has values of 0.05, 96.3, 7.38, and 0.99, correspondingly for z, σ, and d. XXX were taken into consideration as the sample size and were included in the data analysis after accounting for the 10% non-response.16 For every region in the nation, a sample size of XXX was determined with a design effect of 2, 80% statistical power with a two-sided test, and α = 0.05 to detect a 10% decrease. It was assumed that 30% of people had an irregular legal status at time 1 (the current study) and 20% at time 2 (the subsequent study round).17
Ethical considerations
The study was approved by the Institutional Review Board (IRB) in the College of Medicine/University of Baghdad (Approval no. 03-11 on 31st of December 2023), the ethical approval for the current study was uploaded to the Zenodo: Ethical approval and reporting guidelines. https://doi.org/10.5281/zenodo.14037291.18
This project contains the following file: (Ethical approval.jpg).
Data are available under the terms of the Creative Commons Attribution 4.0 International license (CC-BY 4.0).
The obtained data were entered, coded, displayed, and examined using a computer utilizing the IBM SPSS-29 statistical package (IBM Statistical Packages for Social Sciences, version 29, Chicago, IL, USA) that was made accessible as a database software program. Simple metrics of frequency, percentage, mean, standard deviation, and range (minimum-maximum values) were used to present the data.19 The Students-t test was used to determine the significance of the difference between two independent means (quantitative data). When evaluating the significance of differences in percentages (qualitative data), the Pearson Chi-square test (χ2-test) was employed, along with Yate’s adjustment or the Fisher Exact test if necessary. The P value was considered statistically significant if it was equal to or less than 0.05.20
The study included 101 patients with type 2 diabetes mellitus; 52 were receiving metformin, and 49 were receiving either dapagliflozin or empagliflozin. The mean age of the patients was 57±9 for metformin and 54±9 for SGLT2 inhibitors; 63.5% were illiterate, 94.2% of the metformin group and 93.9% of SGLT2 inhibitor group were married, 78.8% of the metformin group and 81.6% of SGLT2 inhibitor group were non-smokers, and 53.8% of metformin group and 57.1% of SGLT2 inhibitor group were hypertensive ( Table 1).
There was no significant difference (p-value > 0.05) in leukocytes, erythrocytes, or epithelial cell counts before and after treatment between the metformin group and the SGLT2 inhibitor group, as shown in Table 2.
Metformin | SGLT-2 Inhibitors | P value MetxSGL2 first visit | P value MetxSGL2 After 12 w | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
First visit | After 12 w | First visit | After 12 w | ||||||||
No | % | No | % | No | % | No | % | ||||
Test | Positive | 2 | 3.8 | 1 | 1.9 | 3 | 6.1 | 5 | 10.2 | 0.598 | 0.078 |
Negative | 50 | 96.2 | 51 | 98.1 | 46 | 93.9 | 44 | 89.8 | |||
P value | 0.558 | 0.461 | |||||||||
Leukocytes (HPF) | 1---2 | 12 | 23.1 | 9 | 17.3 | 3 | 6.1 | 9 | 18.4 | 0.196 | 0.252 |
3---4 | 21 | 40.4 | 35 | 67.3 | 26 | 53.1 | 28 | 57.1 | |||
5---6 | 9 | 17.3 | 4 | 7.7 | 9 | 18.4 | 4 | 8.2 | |||
7---8 | 8 | 15.4 | 3 | 5.8 | 8 | 16.3 | 3 | 6.1 | |||
9---10 | 2 | 3.8 | 1 | 1.9 | 3 | 6.1 | 5 | 10.2 | |||
P value | 0.076 | 0.026 * | |||||||||
Erythrocytes (HPF) | Absent | 3 | 5.8 | 3 | 5.8 | 1 | 2.0 | 3 | 6.1 | 0.663 | 0.630 |
1---2 | 45 | 86.5 | 43 | 82.7 | 41 | 83.7 | 41 | 83.7 | |||
3---4 | 3 | 5.8 | 5 | 9.6 | 4 | 8.2 | 2 | 4.1 | |||
5---6 | - | - | 1 | 1.9 | 1 | 2.0 | 2 | 4.1 | |||
7---8 | - | - | - | - | 1 | 2.0 | - | - | |||
9---10 | 1 | 1.9 | - | - | 1 | 2.0 | 1 | 2.0 | |||
P value | 0.637 | 0.700 | |||||||||
Epithelial cells (HPF) | Absent | 2 | 3.8 | 1 | 1.9 | 2 | 4.1 | 1 | 2.0 | 0.875 | 0.583 |
Few | 29 | 55.8 | 41 | 78.8 | 28 | 57.1 | 34 | 69.4 | |||
[+] | 17 | 32.7 | 8 | 15.4 | 14 | 28.6 | 8 | 16.3 | |||
[++] | 4 | 7.7 | 2 | 3.8 | 4 | 8.2 | 5 | 10.2 | |||
[+++] | - | - | - | - | 1 | 2.0 | 1 | 2.0 | |||
P value | 0.098 | 0.616 |
There was no significant difference (p-value>0.05) in leukocytes, erythrocytes, or epithelial cell counts before and after treatment in the metformin group, as shown in Table 3.
There was a significant difference (p-value = 0.026) in leukocytes and a non-significant difference in erythrocytes and epithelial cell counts before and after treatment in the SGLT2 inhibitor group ( Table 4).
SGLT-2 Inhibitors | First visit | After 12 weeks | P value | |||
---|---|---|---|---|---|---|
No | % | No | % | |||
Test | Positive | 3 | 6.1 | 5 | 10.2 | 0.461 |
Negative | 46 | 93.9 | 44 | 89.8 | ||
Leukocytes (HPF) | 1---2 | 3 | 6.1 | 9 | 18.4 | 0.026 * |
3---4 | 26 | 53.1 | 28 | 57.1 | ||
5---6 | 9 | 18.4 | 4 | 8.2 | ||
7---8 | 8 | 16.3 | 3 | 6.1 | ||
9---10 | 3 | 6.1 | 5 | 10.2 | ||
Erythrocytes (HPF) | Absent | 1 | 2.0 | 3 | 6.1 | 0.700 |
1---2 | 41 | 83.7 | 41 | 83.7 | ||
3---4 | 4 | 8.2 | 2 | 4.1 | ||
5---6 | 1 | 2.0 | 2 | 4.1 | ||
7---8 | 1 | 2.0 | - | - | ||
9---10 | 1 | 2.0 | 1 | 2.0 | ||
Epithelial cells (HPF) | Absent | 2 | 4.1 | 1 | 2.0 | 0.616 |
Few | 28 | 57.1 | 34 | 69.4 | ||
[+] | 14 | 28.6 | 8 | 16.3 | ||
[++] | 4 | 8.2 | 5 | 10.2 | ||
[+++] | 1 | 2.0 | 1 | 2.0 |
There was a significant difference (p-value = 0.043) in leukocytes and a non-significant difference in erythrocytes and epithelial cell counts before and after treatment in the dapagliflozin group, as shown in Table 5.
Oral hypoglycemic drug: Dapagliflozin SGLT-2 INHIBITORS | First Visit | After 12 weeks | P value | |||
---|---|---|---|---|---|---|
No | % | No | % | |||
Test | Positive | 1 | 4.0 | 3 | 12.0 | 0.297 |
Negative | 24 | 96.0 | 22 | 88.0 | ||
Leukocytes (HPF) | 1---2 | 1 | 4.0 | 5 | 20.0 | 0.043 * |
3---4 | 13 | 52.0 | 14 | 56.0 | ||
5---6 | 4 | 16.0 | 3 | 12.0 | ||
7---8 | 6 | 24.0 | - | - | ||
9---10 | 1 | 4.0 | 3 | 12.0 | ||
Erythrocytes (HPF) | Absent | 1 | 4.0 | - | - | 0.798 |
1---2 | 19 | 76.0 | 20 | 80.0 | ||
3---4 | 2 | 8.0 | 2 | 8.0 | ||
5---6 | 1 | 4.0 | 2 | 8.0 | ||
7---8 | 1 | 4.0 | - | - | ||
9---10 | 1 | 4.0 | 1 | 4.0 | ||
Epithelial cells (HPF) | Absent | 1 | 4.0 | - | - | 0.138 |
Few | 11 | 44.0 | 18 | 72.0 | ||
[+] | 11 | 44.0 | 4 | 16.0 | ||
[++] | 2 | 8.0 | 2 | 8.0 | ||
[+++] | - | - | 1 | 4.0 |
There was no significant difference (p-value> 0.05) in leukocytes, erythrocytes, or epithelial cell counts before and after treatment in the empagliflozin group, as shown in Table 6.
Our study’s findings show that the metformin group and the SGLT2 inhibitor group did not significantly differ in their counts of leukocytes, erythrocytes, or epithelial cells before or after treatment, as shown in Table 2. In comparison to other antidiabetic medications, the use of SGLT2 inhibitors is not linked to an increased incidence of UTIs, according to the findings of a study conducted by Wajd Alkabbani in 2022 to evaluate the risk of UTIs related to SGLT2 inhibitors in type 2 diabetes.21 Additionally, Table 3 shows no statistically significant difference in the metformin group’s counts of leukocytes, erythrocytes, or epithelial cells before and after treatment. In a study published in 2022, Fu-Shun Yen compared the morbidity and mortality linked to sepsis and UTI in patients with diabetes between metformin users and nonusers. The findings indicated that among patients with type 2 diabetes, metformin use was not significantly associated with a lower risk of sepsis, recurrent UTI, or UTI. Compared to metformin nonuse, it was linked to a decreased risk of death from a UTI or sepsis.22 In contrast, the SGLT2 inhibitor group’s data revealed a non-significant change in the numbers of erythrocytes and epithelial cells before and after treatment but a significant difference in leukocytes ( Tables 4,5). According to research by Zhigui Zheng, they were published in 2023, dapagliflozin 10 mg/day for a treatment period longer than 24 weeks was associated with a significantly higher risk of urinary tract infection (UTI) than placebo or other active treatments. As a result, patients with type 2 diabetes mellitus should carefully consider the risk of UTI before beginning high-dose, long-term dapagliflozin therapy or adding it on top of existing treatment.23 However, when one of the four SGLT2 inhibitors—dapagliflozin, canagliflozin, empagliflozin, and ipragliflozin is used in a meta-analysis study to estimate the association between the use of these drugs and the risk of UTI, the results indicate that dapagliflozin appears to independently increase the risk of UTI, though the mechanism underlying this intra-class variation in risk is unclear.24 Another study conducted in 2013 by Kristina M. Johnsson revealed a small increase in the incidence of urinary tract infection when type 2 diabetes is treated with once-daily dapagliflozin 5 or 10 mg. Most infections were mild to severe and controlled clinically.25 Our findings about empagliflozin indicated that there was no discernible change in the counts of leukocytes, erythrocytes, or epithelial cells in the group receiving therapy before and after the medication (see Table 6). According to the results of a study conducted in 2024 by Cristina Rebordosa, patients with type 2 diabetes who started taking empagliflozin compared to those who started taking a dipeptidyl peptidase-4 (DPP-4) inhibitor had higher risks of DKA and GI and lower risks of ALI, AKI, CKD, and severe UTI complications when using empagliflozin.26 However, results from a study conducted in 2021 by Arbinda Pokhare on type 2 diabetes patients using empagliflozin revealed that UTIs (17.8%), nasopharyngitis (11.9%), and hypoglycemia (10.71%) were the most often reported side effects of the medication.27 According to Chunmei Xu’s study, SGLT2i was found to have comparable anti-hyperglycemic efficacy to metformin monotherapy, including reducing blood glucose and HbA1c without significantly raising the incidence of UTIs. It also significantly reduced cardiovascular risk factors. However, a study by Mustafa Tanriverdi28 revealed that glucosuria and SGLT-2i use predicted UTI in T2D patients. It also suggested that urine culture is crucial when determining the kind and mode of administration of antibacterial treatment, particularly for patients on SGLT-2i treatment.29 In contrast to individuals on non-SGLT2 inhibitors, patients taking dapagliflozin and empagliflozin had a higher incidence of UTIs, according to a study by Uitracul. Furthermore, when treated with SGLT2 inhibitors, patients who were older and female had a considerably higher incidence of UTI, but patients who had permanent jobs had a reduced risk.30 Among 17 trials evaluating dapagliflozin, 499 events suggestive of UTIs were recorded in 7145 participants (raw event rate 7.0%). A meta-analysis of these trials revealed that, in comparison to the control, dapagliflozin was linked to an increased risk of events that could be indicative of UTIs.31 Furthermore, SGLT2 inhibitor-induced glucosuria probably contributes to an increased risk of genital infections and urinary tract infections to a lesser degree. Treatment with SGLT2 inhibitors does not raise the risk of upper UTIs (pyelonephritis). Furthermore, SGLT2 inhibitors have been linked to an increase in benign urine symptoms brought on by osmotic diuresis, such as an increase in urine output. This might have also made it more likely that patients on SGLT2 inhibitors would have been diagnosed with infections.32
Superior evidence could be provided by studying more urinary parameters on a larger sample of T2DM Iraqi patients taking metformin and SGLT-2 Inhibitors and by extending the monitoring period to evaluate the risk and incidence of urinary tract infections among these patients in controlled trials.
Diabetic patients on SGLT-2 inhibitors treatment demonstrated higher leukocyte count than metformin group patients, an indicator and predictor for higher susceptibility to urinary tract infections.
The study was approved by the Institutional Review Board (IRB) in the College of Medicine/University of Baghdad (Approval no. 03-11 on 31st of December 2023), the ethical approval for the current study was uploaded to the Zenodo: Ethical approval and reporting guidelines. https://doi.org/10.5281/zenodo.14037291.18
This project contains the following file:
Data are available under the terms of the Creative Commons Attribution 4.0 International license (CC-BY 4.0).
DNH contributed to conceptualization, data curation, formal analysis, investigation, methodology, project administration, resources, software, validation, visualization, and writing-original draft preparation. SMA contributed to conceptualization, data curation, investigation, methodology, project administration, resources, supervision, writing – review & editing.
Zenodo: “Impact of Metformin vs SGLT-2i on urinary parameters (Latest Version)”, https://doi.org/10.5281/zenodo.14055980.33
This project contains the following underlying data file:
Data are available under the terms of the Creative Commons Attribution 4.0 International license (CC-BY 4.0).
STROBE criteria for cohort studies was used as reporting criteria for the current study. The complete filled-in reporting guideline document for the current study was uploaded to Zenodo: Ethical Approval and Reporting Guidelines. https://doi.org/10.5281/zenodo.14037291.18
This project contains the following file:
Data are available under the terms of the Creative Commons Attribution 4.0 International license (CC-BY 4.0) (https://creativecommons.org/licenses/by/4.0/).
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Is the work clearly and accurately presented and does it cite the current literature?
No
Is the study design appropriate and is the work technically sound?
Yes
Are sufficient details of methods and analysis provided to allow replication by others?
Partly
If applicable, is the statistical analysis and its interpretation appropriate?
No
Are all the source data underlying the results available to ensure full reproducibility?
Yes
Are the conclusions drawn adequately supported by the results?
No
References
1. Zinman B, Wanner C, Lachin JM, Fitchett D, et al.: Empagliflozin, Cardiovascular Outcomes, and Mortality in Type 2 Diabetes.N Engl J Med. 2015; 373 (22): 2117-28 PubMed Abstract | Publisher Full TextCompeting Interests: No competing interests were disclosed.
Reviewer Expertise: Type 2 Diabetes, Genetics, SGLT2i DKA, inpatient glucose management, incretin hormones
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Version 1 21 Nov 24 |
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