Endocrinology · Medical Literature
Dulaglutide versus empagliflozin as add-on therapy to metformin and sulfonylurea in type 2 diabetes: a randomized pilot study with exploratory metabolomic and microbiome analyses.
Abstract
In patients with type 2 diabetes mellitus (T2DM) inadequately controlled with metformin and sulfonylurea, evidence directly comparing glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter 2 inhibitors as add-on therapy is limited; therefore, we compared dulaglutide and empagliflozin in this setting. This 12-week, single-center, randomized, open-label, parallel-group pilot study included a 24-week observational extension. Patients with HbA1c≥7.0% receiving stable doses of metformin and glimepiride were randomized to dulaglutide 0.75 mg/week or empagliflozin 10 mg/day. Doses were uptitrated at week 4 if tolerated and maintained for 12 weeks, with follow-up until week 36. The primary endpoint was the change in HbA1c at week 12. Secondary endpoints included changes in glycemic and obesity-related parameters. Exploratory analyses were performed to assess plasma metabolite profiles using liquid chromatography-mass spectrometry, and gut microbiota using 16S rRNA gene sequencing. Twenty-four patients completed the 12-week study (dulaglutide, n=13; empagliflozin, n=11). Both treatments significantly reduced HbA1c at week 12, with no significant between-group difference. Empagliflozin significantly reduced HOMA-IR, whereas dulaglutide significantly increased HOMA-β. At week 12, empagliflozin was associated with greater reductions in body weight and body fat compared with dulaglutide, whereas these differences were attenuated at week 36. Exploratory analyses suggested potential, modest treatment-related differences in plasma metabolite profiles and microbiome-metabolic associations, without marked alterations in overall microbial diversity. As add-on therapy to metformin and sulfonylurea, both dulaglutide and empagliflozin improved glycemic control, with no significant between-group difference observed in this exploratory pilot study. Empagliflozin induced earlier weight loss, whereas dulaglutide showed more gradual weight reduction over time, accompanied by exploratory findings suggesting possible differences in plasma and microbiome-related metabolic signatures.
Clinical relevance
In adults with type 2 diabetes mellitus inadequately controlled on metformin plus glimepiride, does add-on dulaglutide (GLP-1 receptor agonist) differ from add-on empagliflozin (SGLT-2 inhibitor) in reducing HbA1c at 12 weeks, and do the two agents produce distinct plasma metabolomic and gut microbiome signatures? __SNAPSHOT__ {"studyDesign":"Randomized, open-label, parallel-group pilot study (12-week interventional phase) with a 24-week observational extension (total follow-up to 36 weeks); single-center","setting":"Single center; country not specified in abstract","sampleSize":"n=24 completed the 12-week study (dulaglutide: n=13; empagliflozin: n=11); total enrolled not reported in abstract","population":"Adults with type 2 diabetes mellitus, HbA1c ≥7.0%, receiving stable doses of metformin and glimepiride","intervention":"Dulaglutide 0.75 mg subcutaneously once weekly, uptitrated at week 4 if tolerated, maintained through week 12","comparator":"Empagliflozin 10 mg orally once daily, uptitrated at week 4 if tolerated, maintained through week 12","primaryOutcome":"Change in HbA1c from baseline to week 12","followUp":"36 weeks total (12-week randomized intervention + 24-week observational extension)","fundingSource":"Not reported in abstract"}
Key findings
Both dulaglutide and empagliflozin produced statistically significant reductions in HbA1c at week 12 compared to baseline (direction and magnitude of change not reported in abstract). There was no statistically significant between-group difference in HbA1c reduction at week 12 (absolute difference, confidence interval, and p-value not reported in abstract). Changes in secondary endpoints — including other glycemic parameters and obesity-related measures — are referenced but not quantified in the abstract. Exploratory analyses using liquid chromatography-mass spectrometry and 16S rRNA gene sequencing were performed to characterize plasma metabolite profiles and gut microbiota composition, respectively; results of these analyses are not reported in the abstract. No specific adverse event data, hypoglycemia rates, or between-group safety comparisons are provided in the abstract. NNT and NNH cannot be calculated from available data.
Practice implications
This pilot study suggests that both dulaglutide and empagliflozin provide statistically significant glycemic benefit when added to dual metformin-sulfonylurea therapy, with no detectable superiority of either agent over 12 weeks for HbA1c reduction. However, the absence of reported effect sizes, confidence intervals, and p-values in the available abstract prevents meaningful assessment of the magnitude or clinical importance of these differences or similarities. The study was explicitly designed as a pilot with exploratory aims, and is therefore underpowered to reliably detect between-group differences or exclude clinically meaningful ones. Findings apply narrowly to adults already on stable metformin plus glimepiride with persistent hyperglycemia (HbA1c ≥7.0%); patients with established cardiovascular disease, heart failure, chronic kidney disease, significant renal impairment, or other comorbidities that now commonly drive drug selection in guidelines are not characterized in the abstract and may not have been adequately represented. The metabolomic and microbiome analyses are exploratory and hypothesis-generating only; no mechanistic or causal conclusions can be drawn. The 24-week observational extension is uncontrolled and susceptible to substantial confounding. NOTE: This summary is based solely on the abstract provided; the full dataset, complete results tables, and safety data have not been reviewed, which is a critical limitation of this appraisal. __LIMITATIONS__ Very small sample size (n=24 completers; n=13 vs. n=11), providing severely limited statistical power to detect or exclude clinically meaningful between-group differences in HbA1c or any secondary endpoint,Open-label design introduces performance and detection bias; blinding of participants and outcome assessors was not achieved,Single-center study markedly limits generalizability across health systems, ethnic groups, and practice settings,Uptitration at week 4 introduces dose heterogeneity within each arm; the proportion of patients who uptitrated is not reported,The 24-week extension is observational (not randomized), introducing high risk of confounding and attrition bias,Metabolomic and microbiome endpoints are exploratory, not pre-specified as primary or secondary outcomes with adequate power; results require independent validation,16S rRNA gene sequencing provides limited taxonomic resolution compared to shotgun metagenomics; functional microbiome characterization is constrained,Background sulfonylurea (glimepiride) increases hypoglycemia risk — particularly relevant when adding a GLP-1 receptor agonist — but hypoglycemia data are not reported in the abstract,Funding source is not disclosed, precluding assessment of potential industry sponsorship bias,Country of origin and institutional setting not specified, limiting assessment of population representativeness,Abstract truncation means that secondary outcome results, metabolomic findings, microbiome findings, adverse events, and week-36 data are entirely unavailable for this appraisal __BOTTOM_LINE_CATEGORY__ promising_but_preliminary __BOTTOM_LINE__ This small, open-label pilot study (n=24) found that both dulaglutide and empagliflozin significantly reduced HbA1c at 12 weeks when added to metformin plus glimepiride, with no statistically significant difference between agents, but effect sizes and confidence intervals are not reported in the available abstract. The exploratory metabolomic and microbiome analyses are hypothesis-generating only and insufficient to guide drug selection. Given the pilot design, very small sample, open-label methodology, and incomplete reporting, these findings should not influence prescribing practice; selection between a GLP-1 receptor agonist and an SGLT-2 inhibitor in this clinical scenario should continue to be driven by established cardiovascular-renal outcome data, tolerability, and individual patient factors.