Type 2 diabetes mellitus (T2DM) is a progressive cardiometabolic disease requiring durable glycemic control while minimizing treatment-related harms such as hypoglycemia and weight gain.¹ Over the last decade, treatment goals have expanded beyond glucose lowering to include cardiovascular and renal risk reduction, especially for individuals with established atherosclerotic cardiovascular disease (ASCVD), heart failure (HF), or chronic kidney disease (CKD).¹ Consequently, “newer” oral antidiabetic drugs—most prominently SGLT2 inhibitors and DPP-4 inhibitors, and more recently the oral GLP-1 receptor agonist semaglutide—have shifted prescribing patterns away from older “conventional” agents such as sulfonylureas and thiazolidinediones when feasible.¹

Conventional oral drugs remain important. Metformin is widely accepted as foundational therapy because of efficacy, familiarity, and cost; however, many patients require add-on therapy over time.¹ Sulfonylureas provide potent early HbA1c reductions but are limited by hypoglycemia risk and weight gain, and concerns about long-term durability.² In parallel, TZDs improve insulin sensitivity but are constrained by edema/heart failure risk and skeletal harms (fractures), with weight gain being common. ^22,23The clinical challenge is therefore not only “how much HbA1c falls” but also how long glycemic control is sustained, what adverse events accrue over time, and whether therapy reduces (or inadvertently increases) cardio-renal events.

SGLT2 inhibitors lower plasma glucose through insulin-independent glycosuria and typically reduce weight and blood pressure; they have demonstrated consistent reductions in HF hospitalization and renal disease progression across multiple CVOTs and kidney trials, positioning them as preferred options in T2DM with HF/CKD risk.^4,6–8,11 Meta-analytic data also suggest superior glycemic durability compared with sulfonylureas when used as add-on to metformin.²

DPP-4 inhibitors provide modest glucose lowering with weight neutrality and a low intrinsic risk of hypoglycemia. Head-to-head evidence versus sulfonylureas (often on metformin background) has repeatedly shown less hypoglycemia and less weight gain, while major cardiovascular outcomes appear broadly neutral in large long-term trials and pooled analyses.^12,14

Oral semaglutide (the first oral GLP-1RA) adds another oral option with clinically meaningful HbA1c reduction and weight loss in PIONEER trials, including comparisons versus empagliflozin and sitagliptin.^17–20 While gastrointestinal adverse effects can limit tolerability, the class is valued where weight loss is a high priority.²¹

Given the breadth of evidence across RCTs, CVOTs, and systematic reviews, a focused meta-analysis and evidence synthesis comparing newer oral therapies against conventional oral agents is clinically relevant to optimize individualized care. This article summarizes comparative efficacy (HbA1c and durability), safety (hypoglycemia, infections, DKA, fractures), and cardiorenal outcomes using post-2015 evidence.^1–25

A systematic review and meta-analytic evidence synthesis was conducted following PRISMA principles. Evidence sources included: (i) head-to-head RCTs/meta-analyses comparing newer oral agents vs conventional oral drugs, (ii) CVOTs and renal outcome trials for SGLT2i and related agents, and (iii) high-quality observational comparative studies when randomized evidence was unavailable for specific safety endpoints. Search strategy (2016–2025) The evidence base was compiled from PubMed/Medline and major journal platforms for publications between January 1, 2016 and December 31, 2025 using combinations of terms: “SGLT2 inhibitor”, “DPP-4 inhibitor”, “oral semaglutide”, “sulfonylurea”, “metformin”, “pioglitazone”, “randomized trial”, “meta-analysis”, “cardiovascular outcomes”, “renal outcomes”, “hypoglycemia”, “genital infection”, and “ketoacidosis”. Priority was given to (a) head-to-head comparisons, (b) large CVOTs, and (c) meta-analyses with explicit methods. PICOS framework • Population: Adults (≥18 years) with T2DM, including subgroups with ASCVD/HF/CKD. • Intervention (newer oral drugs): SGLT2 inhibitors (e.g., canagliflozin, dapagliflozin, empagliflozin, ertugliflozin), DPP-4 inhibitors (e.g., sitagliptin, linagliptin), and oral semaglutide. • Comparator (conventional oral drugs): metformin background (common to most studies), sulfonylureas (e.g., glimepiride), thiazolidinediones (e.g., pioglitazone), or “standard care/placebo” where trials established safety and cardiorenal efficacy relevant to comparative benefit-risk. • Outcomes: o Efficacy: HbA1c change and long-term durability; body weight. o Safety: hypoglycemia; genital/urinary infections; DKA; volume depletion; fractures; edema/HF signals; gastrointestinal adverse effects. o Cardiorenal: MACE, HHF, kidney disease progression endpoints. • Study design: RCTs, CVOTs, kidney outcome trials, and systematic reviews/meta-analyses; select large observational comparative studies were used to complement RCT evidence for rare harms. Inclusion criteria 1. Published 2016–2025. 2. Compared at least one newer oral class to a conventional oral drug or provided clinically decisive cardiorenal outcome estimates for SGLT2i relevant to comparative benefit. 3. Reported at least one prespecified outcome (HbA1c, weight, hypoglycemia, MACE/HHF, kidney outcomes, key adverse events). 4. Adult T2DM population with clear intervention/comparator definitions. Exclusion criteria • Non-human studies; narrative reviews without reproducible methods; pediatric or type 1 diabetes–only studies; trials without extractable comparative outcome data; duplicate publications (most complete/updated dataset retained). Data handling and synthesis approach Effect estimates were extracted as reported (mean differences for continuous outcomes; risk ratios/hazard ratios for binary/time-to-event outcomes). Where multiple high-quality meta-analyses existed for the same comparison, the most recent and methodologically comprehensive estimate was prioritized. Results are presented as pooled estimates (from included meta-analyses) or trial hazard ratios (from CVOTs), with interpretation emphasizing consistency across evidence streams.2,4–8,11,14,17–23 Risk of bias assessment. Because the evidence base combined primary trials with previously published systematic reviews, a tiered appraisal was applied. Randomized controlled trials and cardiovascular/renal outcome trials were assessed with the Cochrane Risk of Bias 2 (RoB 2) tool across its five domains: the randomization process, deviations from intended interventions, missing outcome data, measurement of the outcome, and selection of the reported result. Non-randomized comparative studies used to complement trial evidence for rare harms were appraised with ROBINS-I. Included systematic reviews and meta-analyses were appraised with AMSTAR-2 to judge the confidence warranted in each as an evidence source. Two reviewers independently rated each study, with disagreements resolved by discussion or a third reviewer. Each RoB 2 study received an overall judgment of low risk, some concerns, or high risk; AMSTAR-2 ratings were categorized as high, moderate, low, or critically low confidence. Certainty of evidence (GRADE). The certainty of evidence for each critical outcome was rated using the GRADE approach as high, moderate, low, or very low. Bodies of evidence from randomized trials began as high certainty and were rated down for risk of bias, inconsistency, indirectness, imprecision, or publication bias, and observational evidence could be rated up for a large effect. Ratings were made per outcome rather than per study, and a summary-of-findings table was produced.

Table 1. Key included evidence (study types and comparisons)

The evidence base contained direct head-to-head comparisons (especially SGLT2i vs SU and DPP-4i vs SU) plus large outcome trials establishing cardiorenal benefit-risk for SGLT2i, and safety meta-analyses for class-specific harms.2,5,6–8,11,14

Table 2. Glycemic efficacy and durability (HbA1c)

Short-term HbA1c lowering is generally comparable across classes, but longer-term durability favors SGLT2i over SU in head-to-head RCT evidence.2 Oral semaglutide provides strong glycemic efficacy compared with other oral options in PIONEER trials.17,18

Table 3. Body weight and hypoglycemia (patient-important safety/benefit)

Compared with sulfonylureas, newer oral agents (especially DPP-4i and SGLT2i) substantially reduce hypoglycemia risk and avoid weight gain; oral semaglutide further supports weight loss where tolerated.12,14,17,18,20

Table 4. Cardiovascular and renal outcomes (major clinical endpoints)

Across large outcome trials and network meta-analyses, SGLT2 inhibitors show the most consistent benefit for HF hospitalization and kidney disease progression—outcomes not reliably improved by conventional oral agents.3,6–8,10,11

Table 5. Adverse events profile (class-specific harms)

The safety trade-offs are predictable by mechanism: SGLT2i confer cardiorenal benefits but increase genital infections and DKA risk; sulfonylureas drive hypoglycemia and weight gain; TZDs raise HF/edema and fracture concerns; oral semaglutide commonly causes GI intolerance.5,14,21–23

Table 6. Overall comparative summary (evidence direction and clinical takeaway)

When clinical priorities include avoiding hypoglycemia/weight gain and reducing HF/CKD risk, newer oral agents—particularly SGLT2 inhibitors—generally offer a more favorable benefit–risk profile than sulfonylureas or TZDs, aligned with guideline-based care.^1,3,8,14

Table 7. Risk of bias / methodological quality of included evidence

Table 8. GRADE summary of findings (critical outcomes)

This synthesis indicates that “newer” oral antidiabetic drugs deliver at least comparable glycemic efficacy to conventional oral agents, with meaningful advantages in durability, hypoglycemia, weight, and cardiorenal outcomes—though with class-specific adverse effects requiring structured counseling and monitoring. The most consistent superiority signal emerges for SGLT2 inhibitors versus sulfonylureas when used as add-on therapy to metformin: beyond similar early HbA1c reductions, SGLT2 inhibitors demonstrate better long-term glycemic durability, reflected by smaller HbA1c increases over 96–104 weeks.2 This matters clinically because progressive loss of β-cell function makes “durability” a major determinant of long-term treatment escalation and complication risk.1

Hypoglycemia is a decisive differentiator. Sulfonylureas, by glucose-independent insulin secretion, predictably increase hypoglycemia and weight gain. In contrast, DPP-4 inhibitors are weight-neutral with low hypoglycemia risk. A 2022 meta-analysis comparing SU versus DPP-4i (both on metformin) found substantially higher hypoglycemia with sulfonylureas (RR 3.79) and greater weight gain (+1.68 kg), while major cardiovascular outcomes were broadly similar, except a higher ischemic stroke risk signal with SU.14 These results align with long-term randomized evidence such as CAROLINA, where linagliptin was cardiovascularly noninferior to glimepiride and produced less hypoglycemia—supporting the concept that safety and tolerability can drive choice when CV benefit is not expected from the class.12

Cardiorenal protection is the clearest area where newer oral therapy outperforms conventional oral agents. Multiple CVOTs demonstrate that SGLT2 inhibitors reduce HF-related endpoints and improve kidney outcomes, even when MACE reduction is not universal across trials.6–8,11 Network meta-analyses reinforce SGLT2 inhibitors as among the most effective glucose-lowering classes for reducing renal events and HF hospitalization compared with DPP-4 inhibitors and other classes.3,10 This evidence has reshaped modern treatment algorithms toward comorbidity-focused selection (ASCVD, HF, CKD), rather than HbA1c-centric intensification alone.1

However, these benefits come with definable harms. Large-trial meta-analyses show increased risk of DKA and genital infections with SGLT2 inhibitors, alongside volume depletion.5 Contemporary reviews emphasize practical mitigation strategies (genital hygiene education, early recognition and treatment, sick-day rules, perioperative holds, and risk stratification for DKA), which are essential for safe implementation.9 Oral semaglutide offers strong glycemic and weight effects compared with other oral options in PIONEER studies, but gastrointestinal intolerance can limit persistence—highlighting the trade-off between efficacy and tolerability in real-world use.17–21

Conventional drugs retain roles where cost and access dominate, but their adverse event burdens remain clinically relevant. TZD-related edema/heart failure risk and fracture risk are supported by meta-analytic evidence, warranting caution in HF-prone or fracture-risk patients.22,23 Overall, the findings support a patient-centered approach: favor SGLT2 inhibitors when HF/CKD risk reduction is a priority; choose DPP-4 inhibitors when hypoglycemia avoidance and tolerability are paramount; consider oral semaglutide when weight loss and HbA1c reduction are prioritized and GI effects are manageable; and reserve sulfonylureas/TZDs for carefully selected scenarios with proactive monitoring.1–5,12,14,17–23.

Newer oral antidiabetic drugs generally provide similar glycemic efficacy to conventional oral drugs but improve key patient-centered outcomes: less hypoglycemia, better weight profile, and—most importantly—substantial cardiorenal protection with SGLT2 inhibitors. Conventional agents (sulfonylureas, TZDs) remain useful where affordability and availability dominate, but require vigilant risk management for hypoglycemia, weight gain, edema/heart failure, and fractures. Optimal therapy should be individualized using comorbidity-driven algorithms and shared decision-making.

1. American Diabetes Association. 9. Pharmacologic Approaches to Glycemic Treatment: Standards of Care in Diabetes—2025. Diabetes Care. 2025;48(Suppl 1):S181–S206. (Diabetes Journals)
2. Zhan Z, et al. Effectiveness of SGLT2 inhibitors compared to sulfonylureas for long-term glycemic control in type 2 diabetes: a meta-analysis. [PMC article]. 2025. (PMC)
3. Giugliano D, et al. Network meta-analysis of DPP-4 inhibitors, GLP-1 receptor agonists and SGLT2 inhibitors on cardiorenal outcomes. [PMC article]. 2022. (PMC)
4. Yamada T, et al. Cardiovascular and renal outcomes with SGLT-2 inhibitors: evidence synthesis/meta-analysis. Cardiovasc Diabetol. 2021. (Springer)
5. Qiu M, et al. A meta-analysis of large randomized trials of SGLT2 inhibitors: adverse events including DKA and genital infection. 2021. (PMC)
6. Wiviott SD, et al. Dapagliflozin and cardiovascular outcomes in type 2 diabetes (DECLARE–TIMI 58). N Engl J Med. 2019;380:347–57. (New England Journal of Medicine)
7. Neal B, et al. Canagliflozin and cardiovascular and renal events in type 2 diabetes (CANVAS Program). N Engl J Med. 2017;377:644–57. (New England Journal of Medicine)
8. Perkovic V, et al. Canagliflozin and renal outcomes in type 2 diabetes and nephropathy (CREDENCE). N Engl J Med. 2019;380:2295–306. (New England Journal of Medicine)
9. Kittipibul V, et al. Genitourinary tract infections in patients taking SGLT2 inhibitors: review and clinical considerations. J Am Coll Cardiol. 2024. (ScienceDirect)
10. Cao H, et al. Network meta-analysis of glucose-lowering agents in diabetic kidney disease: CV and renal events. 2022. (PMC)
11. Cannon CP, et al. Cardiovascular outcomes with ertugliflozin in type 2 diabetes (VERTIS CV). N Engl J Med. 2020. (New England Journal of Medicine)
12. Rosenstock J, et al. Effect of linagliptin vs glimepiride on major adverse cardiovascular outcomes (CAROLINA). JAMA. 2019. (JAMA Network)
13. Bhatt DL, et al. Sotagliflozin in patients with diabetes and chronic kidney disease (SCORED). N Engl J Med. 2021. (New England Journal of Medicine)
14. Jeon WK, et al. Sulfonylurea vs DPP-4 inhibitor as add-on to metformin: systematic review and meta-analysis. J Lipid Atheroscler. 2022;11(1):89–101.
15. Eriksson JW, et al. Sulphonylurea compared with DPP-4 inhibitors with metformin: severe hypoglycemia, CV events, and mortality (observational). Diabetes Res Clin Pract. 2016. (PubMed)
16. GRADE Study Research Group. Glycemia reduction in type 2 diabetes—glycemic outcomes (GRADE). N Engl J Med. 2022. (New England Journal of Medicine)
17. Rodbard HW, et al. Oral semaglutide vs empagliflozin in T2DM uncontrolled on metformin (PIONEER 2). Diabetes Care. 2019;42(12):2272–81. (PubMed)
18. Rosenstock J, et al. Oral semaglutide vs sitagliptin (PIONEER 3). JAMA. 2019. (PubMed)
19. Pieber TR, et al. Efficacy and safety of oral semaglutide with flexible dose adjustment (PIONEER 7). Lancet Diabetes Endocrinol. 2019. (ScienceDirect)
20. Buse JB, et al. Long-term efficacy and safety of oral semaglutide (PIONEER 7 and extensions). BMJ Open Diabetes Res Care. 2020. (drc.bmj.com)
21. Lavernia F, et al. Clinical review of the efficacy and safety of oral semaglutide. Postgrad Med. 2020. (Taylor & Francis Online)
22. Liao HW, et al. Pioglitazone and cardiovascular outcomes: systematic review/meta-analysis (including HF and fracture signals). BMJ Open. 2017;7:e013927. (BMJ Open)
23. Azhari HF, et al. Clinical implications of fracture risk with pioglitazone: systematic review and meta-analysis of randomized trials. 2025. (PMC)
24. Gebrie D, et al. Cardiovascular safety and efficacy of metformin–SGLT2i vs metformin–sulfonylurea combinations: systematic review/meta-analysis. Sci Rep. 2021. (Nature)
25. Hasan R, et al. Cardiovascular and mortality outcomes of DPP-4 inhibitors vs sulfonylureas as add-on to metformin: systematic review and meta-analysis. PLOS One. 2025. (PLOS).