Effect of SGLT2 inhibitors on fractures, BMD, and bone metabolism markers in patients with type 2 diabetes mellitus: a systematic review and meta-analysis

Is the Impact of Sodium-Glucose Co-Transporter 2 (SGLT2) Inhibitors on Bone Metabolism and Fracture Incidence a Class or Drug Effect? A Narrative Review

Background/Objectives: Type 2 diabetes mellitus (T2DM) has a growing prevalence, even in developed countries. Because of the increase in life expectancy, the number of older people with T2DM is also increasing. The management and handling of these patients is challenging due to its co-morbidities. Aim: In the present study, we reviewed the literature in order to investigate the impact of sodium-glucose co-transporter 2 inhibitors (SGLT-2 inhibitors) on bone metabolism and fracture incidence. Methods: We searched the literature using the databases of PubMed, CENTRAL and Cochrane Central Register of Controlled Trials up to December 2024. Results: There is a controversial position in the literature concerning the effects of SGLT2 inhibitors when administered in T2DM, with respect to bone metabolism and bone fracture incidence. Multiple studies suggest the SGLT2 inhibitors have a disadvantageous effect on bone metabolism and fracture incidence, while several others suggest a beneficial effect. Conclusions: Patients with type 2 diabetes mellitus are at high risk of alterations in their bone metabolism. SGLT2 inhibitors are a novel class with pleiotropic effects in many organs, such as the kidneys and heart, although their effect on bone metabolism and fracture incidence is still unclear. Until we have more clinical data, all caregivers (medical and nursing staff) should be aware of possible bone fractures in patients receiving this class of agents.

Cardiovascular therapeutic targets of sodium-glucose co-transporter 2 (SGLT2) inhibitors beyond heart failure

Sodium-glucose co-transporter 2 (SGLT2) inhibitors are oral antidiabetic agents that have shown significant improvements in cardiovascular and renal outcomes among patients with heart failure (HF), regardless of diabetic status, establishing them as a cornerstone therapy. In addition to glycemic control and the osmotic diuretic effect, the inhibition of SGLT2 improves endothelial function and vasodilation, optimizing myocardial energy metabolism and preserving cardiac contractility. Moreover, SGLT2 inhibitors may exhibit anti-inflammatory properties and attenuate acute myocardial ischemia/reperfusion injury, thereby reducing cardiac infarct size, enhancing left ventricular function, and mitigating arrhythmias. These pleiotropic effects have demonstrated efficacy across various cardiovascular conditions, ranging from acute to chronic coronary syndromes and extending to arrhythmias, valvular heart disease, cardiomyopathies, cardio-oncology, and cerebrovascular disease. This review provides an overview of the current literature on the potential mechanisms underlying the effectiveness of SGLT2 inhibitors across a wide range of cardiovascular diseases beyond HF.

The effect of antidiabetic drugs on bone metabolism: a concise review

Diabetes mellitus (DM) is a complex metabolic disorder characterized by chronic hyperglycemia, which derives from either insufficient insulin production [type 1 diabetes mellitus (T1DM)] or both impaired insulin sensitivity along with inadequate insulin production [type 2 diabetes mellitus (T2DM)] and affects millions of people worldwide. In addition to the adverse effects of DM on classical target organs and tissues, skeletal health can also be adversely affected. There is considerable evidence linking DM with osteoporosis. The fracture risk in patients with DM differs upon the type of diabetes, and it appears to be related to the type of anti-diabetic treatment. Antidiabetic drugs may have various effects on bone health. Most of them have neutral or even favorable effects on bone metabolism with the exception of thiazolidinediones (TZDs). Some studies suggest that TZDs may have negative impact on bone health by decreasing bone formation and increasing the fracture risk. There are also limited studies linking the use of canagliflozin, a Sodium-glucose contransporter-2 inhibitor (SGLT2i), with increased fracture risk. On the other hand, therapies that are based on incretin effect, like Dipeptidyl peptidase-4 inhibitors (DPP-4i) and Glucagon-like peptide-1 receptor agonizts (GLP-1RAs) might have positive effects on bone health by promoting bone formation. Herein we review the impact of antidiabetic drugs on bone health, highlighting the potential benefits and risks associated with these medications in an attempt to contribute to the development of personalized treatment strategies for individuals with DM.

Effects of sodium-glucose cotransporter 2 (SGLT2) inhibitors, dapagliflozin and canagliflozin, on the musculoskeletal system in an experimental model of diabetes induced by high-fat diet and streptozotocin in rats

The effect of SGLT2 inhibitors, a new group of antidiabetic drugs, on the skeletal system is a matter of debate. There are concerns that they may unfavorably affect bones. The aim of the study was to investigate the effects of dapagliflozin and canagliflozin on musculoskeletal system in an experimental rat model of type 2 diabetes induced by a high-fat diet (HFD) and streptozotocin (STZ). The experiments were carried out on mature female rats. To induce diabetes, STZ was administered 2 weeks after the introduction of HFD. Administration of dapagliflozin (1.4 mg/kg p.o.) or canagliflozin (4.2 mg/kg p.o.) started 1 week after the STZ injection, and lasted 4 weeks. Skeletal muscle mass and strength, serum bone turnover marker concentration and other biochemical parameters, and bone mass, density, histomorphometric parameters and mechanical properties were determined. Diabetes induced decreases in skeletal muscle mass and osteoporotic changes, including decreases in bone density, and worsening of the histomorphometric parameters and cancellous bone mechanical properties. The SGLT2 inhibitors decreased glycemia and other diabetes-induced metabolic changes, and counteracted only some unfavorable effects of diabetes on bones. The effects of dapagliflozin and canagliflozin on metabolic parameters were similar, whereas there were some differences in their effects on the skeletal system. The study demonstrated possibility of differential skeletal effects of different SGLT2 inhibitors in diabetic conditions, indicating the need for caution concerning their use in patients at risk of bone fractures.

A Randomized Controlled Trial on the Effect of Luseogliflozin on Bone Microarchitecture Evaluated Using HR-pQCT in Elderly Type 2 Diabetes

INTRODUCTION

Bone fragility is a critical issue in the treatment of elderly people with type 2 diabetes (T2D). In the Canagliflozin Cardiovascular Assessment Study, the subjects with T2D who were treated with canagliflozin showed a significant increase in fracture events compared to a placebo group as early as 12 weeks post-initiation. In addition, it has been unclear whether sodium-glucose co-transporter 2 (SGLT2) inhibitors promote bone fragility. We used high-resolution peripheral quantitative computed tomography (HR-pQCT) to prospectively evaluate the short-term effect of the SGLT2 inhibitor luseogliflozin on bone strength and microarchitecture in elderly people with T2D.

METHODS

This was a single-center, randomized, open-label, active-controlled pilot trial for ≥ 60-year-old Japanese individuals with T2D without osteoporosis. A total of 22 subjects (seven women and 15 men) were randomly assigned to a Lusefi group (added luseogliflozin 2.5 mg) or a control group (added metformin 500 mg) and treated for 48 weeks. We used the second-generation HR-pQCT (Xtreme CT II®, Scanco Medical, Brüttisellen, Switzerland) before and 48 weeks after the treatment to evaluate the subjects' bone microarchitecture and estimate their bone strength.

RESULTS

Twenty subjects (Lusefi group, n = 9; control group, n = 11) completed the study, with no fracture events. As the primary outcome, the 48-week changes in the bone strength (stiffness and failure load) estimated by micro-finite element analysis were not significantly different between the groups. As the secondary outcome, the changes in all of the cortical/trabecular microarchitectural parameters at the radius and tibia from baseline to 48 weeks were not significantly different between the groups.

CONCLUSIONS

In the pilot trial, we observed no negative effect of 48-week luseogliflozin treatment on bone microarchitecture or bone strength in elderly people with T2D.

TRIAL REGISTRATION

UMIN-CTR no. 000036202 and jRCT 071180061.

Complex actions of sodium glucose transporter-2 inhibitors on lipids, calcific atherosclerosis, and bone density

PURPOSE OF REVIEW

Inhibitors of sodium-glucose cotransporter-2 (SGLT2) lower renal glucose reabsorption and, thus, are used to treat patients with type 2 diabetes mellitus. Clinical trials coincidentally showed that SGLT2 inhibitors also benefitted patients with heart failure. This review explores the impact of SGLT2 inhibitors on other aspects of cardiovascular disease and skeletal health.

RECENT FINDINGS

In some, but not all, clinical and preclinical studies, SGLT2 inhibitors are found to reduce serum levels of free fatty acids and triglycerides. Their effects on total and low-density lipoprotein cholesterol and cardiac function also vary. However, SGLT2 inhibitors reduce lipid accumulation in the liver, kidney, and heart, and alter expression of lipid metabolism genes. Effects on free fatty acid uptake in abdominal fat depots depend on the location of adipose tissue. In male, but not female, mice, SGLT2 inhibitors reduce the atherosclerotic lesions and aortic calcium deposition. With respect to skeletal health, recent literature has reported conflicting associations with the risks of fracture and amputation.

SUMMARY

Studies suggest that SGLT2 inhibitors reduce tissue lipid accumulation, and in a sex-dependent manner, atherosclerosis and vascular calcification. However, their effects on lipid levels and bone health are complex and remain to be established.

A comprehensive meta-analysis on the association of SGLT2is and GLP-1RAs with vascular diseases, digestive diseases and fractures

AIM

Sodium-glucose cotransporter-2 inhibitors (SGLT2is) and glucagon-like peptide 1 receptor agonists (GLP-1RAs) are two new classes of antidiabetic agents. We aimed to evaluate the association between these two drug classes and risk of various vascular diseases, digestive diseases and fractures.

METHODS

Large randomized trials of SGLT2is and GLP-1RAs were included. Outcomes of interest were the various serious adverse events related to vascular diseases, digestive diseases and fractures. We performed meta-analyses using synthesize risk ratio (RR) and 95% confidence interval (CI) as effect size.

RESULTS

We included 27 large trials. SGLT2is had significant association with less hypertension (RR 0.70, 95% CI 0.54-0.91), hypertensive crisis (RR 0.63, 95% CI 0.47-0.84), varicose vein (RR 0.34, 95% CI 0.13-0.92), and vomiting (RR 0.55, 95% CI 0.31-0.97); but more spinal compression fracture (RR 1.73, 95% CI 1.02-2.92) and tibia fracture. GLP-1RAs had significant association with more deep vein thrombosis (RR 1.92, 95% CI 1.23-3.00), pancreatitis (RR 1.54, 95% CI 1.07-2.22), and cholecystitis acute (RR 1.51, 95% CI 1.08-2.09); but less rib fracture (RR 0.59, 95% CI 0.35-0.97). Sensitivity analyses suggested that our findings were robust.

CONCLUSIONS

SGLT2is may have protective effects against specific vascular and digestive diseases, whereas they may increase the incidence of site-specific fractures (e.g., spinal compression fracture). GLP-1RAs may have protective effects against site-specific fractures (i.e., rib fracture), whereas they may increase the incidence of specific vascular and digestive diseases. These findings may help to make a choice between SGLT2is and GLP-1RAs in clinical practice.

Fractures in women with type 2 diabetes are associated with marked deficits in cortical parameters and trabecular plates

The basis for increased fracture risk in type 2 diabetes (T2DM) is not well understood. In this multi-ethnic, population-based study (n = 565), we investigated bone microstructure, trabecular plate/rod morphology, and mineralization in women with T2DM (n = 175) with and without fracture using a second-generation HRpQCT and individual trabecula segmentation and mineralization (ITS; ITM). Covariate-adjusted aBMD was 3.0%-6.5% higher at all sites (all p<.005) in T2DM vs controls. By HRpQCT, T2DM had higher covariate-adjusted trabecular vBMD (5.3%-6.4%) and number (3.8%-5.1%) and greater cortical area at the radius and tibia. Covariate-adjusted cortical porosity was 10.0% higher at the tibia only in T2DM vs controls, but failure load did not differ. Among women with T2DM, those with adult atraumatic fracture (n = 59) had 5.2%-8.5% lower adjusted aBMD at all sites by DXA compared with those without fracture (n = 103). By HRpQCT, those with fracture had lower adjusted total vBMD and smaller cortical area (10.2%-16.1%), lower cortical thickness (10.5-15.8%) and lower cortical vBMD associated with 18.1 and 17.2% lower failure load at the radius and tibia, respectively (all p<.05); plate volume and thickness were 5.7% and 4.7% lower, respectively, (p<.05) while rod volume fraction was 12.8% higher in the fracture group at the tibia only. Sodium glucose cotransporter 2 inhibitor users (SGLT2i; n = 19), tended to have lower radial rod tissue mineral density by ITS (p=.06). GLP1 agonist users (n = 19) had trabecular deficits at both sites and higher cortical porosity and larger pores at the distal tibia. In summary, T2DM is associated with increased cortical porosity while those with T2DM and fracture have more marked cortical deficits and fewer trabecular plates associated with lower failure load.

A multicentre, double-blind, placebo-controlled, randomized, parallel comparison, phase 3 trial to evaluate the efficacy and safety of pioglitazone add-on therapy in type 2 diabetic patients treated with metformin and dapagliflozin

AIM

To investigate the efficacy and safety of pioglitazone compared to placebo when added to metformin plus dapagliflozin, a sodium-glucose cotransporter-2 (SGLT2) inhibitor, for patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

In a multicentre study, with a randomized, double-blind, placebo-controlled design, 249 Korean patients with T2DM suboptimally managed on metformin and dapagliflozin were assigned to receive either pioglitazone (15 mg daily) or placebo for 24 weeks, followed by a 24-week pioglitazone extension. Primary outcomes included changes in glycated haemoglobin (HbA1c), with secondary outcomes assessing insulin resistance, adiponectin levels, lipid profiles, liver enzymes, body weight and waist circumference.

RESULTS

Pioglitazone administration resulted in a significant reduction in HbA1c levels (from 7.80% ± 0.72% to 7.27% ± 0.82%) compared with placebo (from 7.79% ± 0.76% to 7.69% ± 0.86%, corrected mean difference: -0.42% ± 0.08%; p < 0.01) at 24 weeks. Additional benefits from pioglitazone treatment included enhanced insulin sensitivity, increased adiponectin levels, raised high-density lipoprotein cholesterol levels and reduced liver enzyme levels, resulting in improvement in nonalcoholic fatty liver disease liver fat score. Despite no serious adverse events in either group, pioglitazone therapy was modestly but significantly associated with weight gain and increased waist circumference.

CONCLUSIONS

Adjunctive pioglitazone treatment in T2DM inadequately controlled with metformin and dapagliflozin demonstrates considerable glycaemic improvement, metabolic benefits, and a low risk of hypoglycaemia. These advantages must be weighed against the potential for weight gain and increased waist circumference.

The relationship between use of SGLT2is and incidence of respiratory and infectious diseases and site-specific fractures: a meta-analysis based on 32 large RCTs

OBJECTIVES

We aimed to evaluate the relationship between use of sodium-glucose cotransporter-2 inhibitors (SGLT2is) and incidence of various respiratory and infectious diseases and site-specific fractures.

METHODS

Large randomized controlled trials (RCTs) of SGLT2is enrolling more than 400 subjects were included. Outcomes of interest were various serious adverse events regarding to respiratory and infectious disorders and site-specific fractures. Meta-analysis was done using risk ratio (RR) and 95% confidence interval (CI) as effect size.

RESULTS

Thirty-two large RCTs were included in this meta-analysis. Use of SGLT2is was significantly associated with the lower incidences of 6 kinds of noninfectious respiratory diseases {e.g., Asthma (RR 0.64, 95% CI 0.43-0.96; P = 0.0299), Chronic obstructive pulmonary disease [COPD] (RR 0.75, 95% CI 0.62-0.91; P = 0.0027), and Respiratory failure (RR 0.78, 95% CI 0.61-0.99; P = 0.0447)} and 4 kinds of infectious respiratory diseases {e.g., Bronchitis (RR 0.61, 95% CI 0.46-0.81; P = 0.0007), and Pneumonia (RR 0.85, 95% CI 0.78-0.93; P = 0.0002)}. Use of SGLT2is was not significantly associated with the incidences of 31 kinds of site-specific fractures (e.g., Hip fracture, Femoral neck fracture, and Spinal fracture; P > 0.05).

CONCLUSIONS

Our meta-analysis confirmed the benefits of SGLT2is against 6 kinds of noninfectious respiratory diseases (e.g., Asthma, COPD, and Respiratory failure) and 4 kinds of infectious respiratory diseases (e.g., Bronchitis, and Pneumonia). These findings suggest a likelihood that SGLT2is might be used to prevent or treat these respiratory diseases. Moreover, our meta-analysis for the first time revealed no association between use of SGLT2is and incidence of various site-specific fractures.