Effect of Sitagliptin as Add-on Therapy in Elderly Type 2 Diabetes Patients With Inadequate Glycemic Control in Taiwan

Evaluation of glucose-lowering medications in older people: a comprehensive systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Type 2 diabetes mellitus (T2DM) is increasingly being diagnosed in older adults. Our objective is to assess the advantages and potential drawbacks of different glucose-lowering medications in this specific population.

METHODS

A network meta-analysis was conducted to identify randomized controlled trials that examined patient-centered outcomes in adults aged ≥65 years with T2DM. We searched PubMed, Cochrane CENTRAL, and Embase up to September 23, 2023. Quality of eligible studies were assessed using the Cochrane RoB 2.0 tool.

RESULTS

A total of 22 trials that involved 41 654 participants were included, incorporating sodium-glucose cotransporter-2 (SGLT2) inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1RAs), dipeptidyl peptidase-4 (DPP-4) inhibitors, metformin, sulfonylureas (SU) and acarbose. Our findings reveal that GLP-1RAs reduce the risk of major adverse cardiovascular events (risk ratio [RR], 0.83; 95% confidence interval [CI], 0.71 to 0.97) and body weight (mean difference [MD], -3.87 kg; 95% CI, -5.54 to -2.21). SGLT2 inhibitors prevent hospitalization for heart failure (RR, 0.66; 95% CI, 0.57 to 0.77), renal composite outcome (RR, 0.69; 95% CI, 0.53 to 0.89), and reduce body weights (MD, -1.85 kg; 95% CI, -2.42 to -1.27). SU treatment increases the risk of any hypoglycaemia (RR, 4.19; 95% CI, 3.52 to 4.99) and severe hypoglycaemia (RR, 7.06; 95% CI, 3.03 to 16.43). GLP-1RAs, SGLT2 inhibitors, metformin, SU and DPP-4 inhibitors are effective in reducing glycaemic parameters. Notably, the number of treatments needed decreases in most cases as age increases.

CONCLUSIONS

Novel glucose-lowering medications with benefits that outweigh risks should be prioritized for older patients with diabetes.

Safety of dipeptidyl peptidase-4 inhibitors in older adults with type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials

Registration:

PROSPERO: CRD42020210645

Introduction:

We aimed to assess the safety of dipeptidyl peptidase-4 (DPP-4) inhibitors in older patients with type 2 diabetes with inadequate glycaemic control.

Methods:

We included randomized controlled trials (RCTs) in older (⩾65 years) patients with type 2 diabetes. The intervention group was randomized to treatment with any DPP-4 inhibitors. A systematic search in MEDLINE and Embase was performed in December 2020. For assessing the risk of bias, RoB 2 tool was applied. The quality of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. We pooled outcomes using random effects meta-analyses.

Results:

We identified 16 RCTs that included 19,317 patients with a mean age of greater than 70 years. The mean HbA1c level ranged between 7.1 and 10.0 g/dl. Adding DPP-4 inhibitors to standard care alone may increase mortality slightly [risk ratio (RR) 1.04; 95% confidence interval (CI) 0.89–1.21]. Adding DPP-4 inhibitors to standard care increases the risk for hypoglycaemia (RR 1.08; 95% CI 1.01–1.16), but difference in overall adverse events is negligible. DPP-4 inhibitors added to standard care may reduce mortality compared with sulfonylureas (RR 0.88; 95% CI 0.75–1.04). DPP-4 inhibitors probably reduce the risk for hypoglycaemia compared with sulfonylureas (magnitude of effect not quantifiable because of heterogeneity) but difference in overall adverse events is negligible. There is insufficient evidence on hospitalizations, falls, fractures, renal impairment and pancreatitis.

Conclusion:

There is no evidence that DPP-4 inhibitors in addition to standard care decrease mortality but DPP-4 inhibitors increase hypoglycaemia risk. Second-line therapy in older patients should be considered cautiously even in drugs with a good safety profile such as DPP-4 inhibitors. In case second-line treatment is necessary, DPP-4 inhibitors appear to be preferable to sulfonylureas.

Plain language summary

Safety of dipeptidyl peptidase-4 inhibitors in older adults with type 2 diabetes Introduction: We performed the review to assess the safety of dipeptidyl peptidase-4 (DPP-4) inhibitors in older type 2 diabetes patients with blood sugar outside the normal level. Methods: To answer the question, we searched various electronic databases. We included studies in older (⩾65 years) patients with type 2 diabetes that assessed the safety of DPP-4 inhibitors. The data from the different studies were quantitatively summarized using statistical methods. We assessed the quality of the data to judge the certainty of the findings. Results: We identified 16 studies that included 19,317 patients with a mean age greater than 70 years. The average blood sugar level of patients in the included studies was slightly or moderately increased. Adding DPP-4 inhibitors to standard care alone may increase mortality slightly. Adding DPP-4 inhibitors to standard care increases the risk for hypoglycaemia, but difference in overall adverse events is negligible. DPP-4 inhibitors added to standard care may reduce mortality compared with sulfonylureas. DPP-4s probably reduce the risk of hypoglycaemia compared with sulfonylureas (magnitude of effect not quantifiable because of heterogeneity) but difference in overall adverse events is negligible. There is insufficient evidence on hospitalizations, falls, fractures, renal impairment and pancreatitis. Conclusion: There is no evidence that DPP-4 inhibitors in addition to standard care decrease mortality but DPP-4 inhibitors increase the risk that blood sugar falls below normal. Adding DPP-4 inhibitorss to standard care in older patients should be considered cautiously even in drugs with a good safety profile such as DPP-4 inhibitors. In case additional treatment is necessary, DPP-4 inhibitors appear to be preferable to sulfonylureas.

Dipeptidyl peptidase-4 inhibitor sitagliptin induces vasorelaxation via the activation of Kv channels and PKA

The present study investigated the vasorelaxant effects of sitagliptin, which is a dipeptidyl peptidase-4 (DPP-4) inhibitor in aortic rings pre-contracted with phenylephrine (Phe). Sitagliptin induced vasorelaxation in a concentration-dependent manner but the inhibition of voltage-dependent K⁺ (Kv) channels by pretreatment with 4-aminopyridine (4-AP) effectively reduced this effect. By contrast, the inhibition of inward rectifier K⁺ (Kir) channels by pretreatment with barium (Ba²⁺), large-conductance calcium (Ca²⁺)-activated K⁺ (BK_Ca) channels with paxilline, and adenosine triphosphate (ATP)-sensitive K⁺ (K_ATP) channels with glibenclamide did not change this effect. Although the application of SQ 22536, which is an adenylyl cyclase inhibitor, also did not change this effect, treatment with KT 5720, a protein kinase A (PKA) inhibitor, effectively reduced the vasorelaxant effects of sitagliptin. ODQ, which is a guanylyl cyclase inhibitor, and KT 5823, a protein kinase G (PKG) inhibitor, did not impact the effect. Furthermore, neither the inhibition of Ca²⁺ channels by pretreatment with nifedipine nor the inhibition of sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase (SERCA) pumps by pretreatment with thapsigargin changed the effect. Similarly, the effects of sitagliptin were not altered by eliminating the endothelium, by pretreatment with a nitric oxide (NO) synthase inhibitor (L-NAME), or by inhibition of small- and intermediate-conductance Ca²⁺-activated K⁺ channels (SK_Ca and IK_Ca) using apamin and TRAM-34. Taken together, these results suggest that sitagliptin induces vasorelaxation by inhibiting both membrane potential (Em)-dependent and -independent vasoconstriction and activating PKA and Kv channels independently of PKG signaling pathways, other K⁺ channels, SERCA pumps, and the endothelium.

Effectiveness and safety of dipeptidyl peptidase 4 inhibitors in the management of type 2 diabetes in older adults: a systematic review and development of recommendations to reduce inappropriate prescribing

Background

Preventable drug-related hospital admissions can be associated with drugs used in diabetes and the benefits of strict diabetes control may not outweigh the risks, especially in older populations. The aim of this study was to look for evidence on risks and benefits of DPP-4 inhibitors in older adults and to use this evidence to develop recommendations for the electronic decision support tool of the PRIMA-eDS project.

Methods

Systematic review using a staged approach which searches for systematic reviews and meta-analyses first, then individual studies only if prior searches were inconclusive. The target population were older people (≥65 years old) with type 2 diabetes. We included studies reporting on the efficacy and/or safety of DPP-4 inhibitors for the management of type 2 diabetes. Studies were included irrespective of DPP-4 inhibitors prescribed as monotherapy or in combination with any other drug for the treatment of type 2 diabetes. The target intervention was DPP-4 inhibitors compared to placebo, no treatment, other drugs to treat type 2 diabetes or a non-pharmacological intervention.

Results

Thirty studies (reported in 33 publications) were included: 1 meta-analysis, 17 intervention studies and 12 observational studies. Sixteen studies were focused on older adults and 14 studies reported subgroup analyses in participants ≥65, ≥70, or ≥75 years. Comorbidities were reported by 26 studies and frailty or functional status by one study. There were conflicting findings regarding the effectiveness of DPP-4 inhibitors in older adults. In general, DPP-4 inhibitors showed similar or better safety than placebo and other antidiabetic drugs. However, these safety data are mainly based on short-term outcomes like hypoglycaemia in studies with HbA1c control levels recommended for younger people. One recommendation was developed advising clinicians to reconsider the use of DPP-4 inhibitors for the management of type 2 diabetes in older adults with HbA1c <8.5% because of scarce data on clinically relevant benefits of their use. Twenty-two of the included studies were funded by pharmaceutical companies and authored or co-authored by employees of the sponsor.

Conclusions

Other than the surrogate endpoint of improved glycaemic control, data on clinically relevant benefits of DPP-4 inhibitors in the treatment of type 2 diabetes mellitus in older adults is scarce. DPP-4 inhibitors might have a lower risk of hypoglycaemia compared to other antidiabetic drugs but data show conflicting findings for long-term benefits. Further studies are needed that evaluate the risks and benefits of DPP-4 inhibitors for the management of type 2 diabetes mellitus in older adults, using clinically relevant outcomes and including representative samples of older adults with information on their frailty status and comorbidities. Studies are also needed that are independent of pharmaceutical company involvement.

Electronic supplementary material

The online version of this article (doi:10.1186/s12877-017-0571-8) contains supplementary material, which is available to authorized users.

Dipeptidyl peptidase-4 inhibitors and the risk of heart failure: a systematic review and meta-analysis

BACKGROUND

Given recent discrepant results from randomized controlled trials (RCTs), we examined the totality of RCT evidence assessing the association between dipeptidyl peptidase-4 (DPP-4) inhibitors and heart failure.

METHODS

MEDLINE, Embase and ClinicalTrials.gov were searched without language restrictions to August 2016 for RCTs comparing DPP-4 inhibitors to placebo or no therapy for a period of 24 weeks or more. We included all heart failure outcomes when listed either as a serious adverse event or adverse event. Pooled analyses used random-effects.

RESULTS

We identified 100 RCTs (n = 79 867) - 3 large cardiovascular-safety RCTs (SAVOR-TIMI 53[saxagliptin]/n = 16 492, EXAMINE[alogliptin]/n = 5380, and TECOS[sitagliptin]/n = 14 735), and 97 smaller RCTs with a primary outcome that was usually change in glycated hemoglobin. Virtually all RCTs were high-quality, multicentre, placebo-controlled trials. A total of 96% (1192/1244) of heart failure events were prespecified, blindly adjudicated and required hospital admission. Pooled results suggested a 13% increase in heart failure (relative risk [RR] 1.13, 95% confidence interval [CI] 1.01-1.26, I2 = 0%; 32 RCTs, n = 54 640, 1244 events). When including only the 3 large RCTs, the increase was similar, but not significant (RR 1.14, 95% CI 0.97-1.32; 3 RCTs, n = 36 543, 1169 adjudicated events; number needed to harm 246) owing to heterogeneity (I2 = 42%), which lead to wider CIs, because SAVOR-TIMI 53 showed increased heart failure (RR 1.26, 95% CI 1.06-1.49) and TECOS showed no effect (RR 1.00, 95% CI 0.83-1.19).

INTERPRETATION

Despite pooled data from 79 867 patients, whether DPP-4 inhibitors increase heart failure overall or exhibit within-class differences remains unresolved. Our results highlight the importance of ongoing trials that are comparing DPP-4 inhibitors to placebo, although no large cardiovascular-safety RCTs are comparing different DPP-4 inhibitors to each other; consequently, these will address the overall but not class-difference question.

Sitagliptin: Is It Effective in Routine Clinical Practice?

Aim. The present study was conducted to determine the glycaemic effects of sitagliptin in type 2 diabetes patients. Methods. Data was collected from patient medical records of a major teaching hospital in Malaysia, from 2009 to 2012. Glycated hemoglobin (HbA1c) values prior to and up to 12 months after the initiation of sitagliptin were analysed. The change in HbA1c values was accounted for based on a generalized linear model generated using the Generalized Estimating Equations (GEE) method. Results and Discussion. Of the 457 patients, 53.6% were elderly and 81.4% were overweight. The mean HbA1c (standard deviation) before initiation of sitagliptin was 8.5 (1.4)%. This dropped to 7.7 (1.4)%, 3 to 6 months after initiation of sitagliptin, with a mean difference of 0.8% (95% confidence interval (CI): 0.7-1.0; P < 0.001). However, this value increased to 8.0 (1.7)% after 7 to 12 months on sitagliptin (P = 0.002) with a mean difference from baseline of 0.6% (95% CI: 0.4-0.7; P < 0.001). Conclusion. In routine clinical practice, sitagliptin produces a significant reduction in mean HbA1c (0.8%) within the first 6 months of use which corresponds to efficacy data obtained in controlled clinical trials. However, this reduction was lesser, 7 to 12 month later.

Real-world effectiveness of sitagliptin as add-on therapy in patients with type 2 diabetes mellitus

AIMS

To assess the effectiveness of sitagliptin in glycemic control in a clinical practice.

METHODS

This was a retrospective medical chart review study conducted in a single hospital. A total of 3081 patients with diabetes mellitus who were prescribed sitagliptin were selected, including 2729 continuous sitagliptin users (defined as continuous usage ≥ 24 weeks) and 352 subjects who used sitagliptin for < 24 weeks. An additional 12-month observation period was monitored after initiating sitagliptin to extract clinical information at 3, 6, 9, and 12 months through patient medical chart review.

RESULTS

In the 2729 continuous users, a baseline glycated hemoglobin (HbA1c) level of 9.0% was reduced to 8.1%, 8.1%, 8.1%, and 8.2% at 3, 6, 9, and 12 months, respectively, representing a 0.9% HbA1c level reduction at 3, 6, and 9 months and a 0.8% HbA1c level reduction at 12 months. With a goal of HbA1c value of < 7.0%, 9.1% of the patients were under control at baseline; after initiating sitagliptin, 22.7% of the patients achieved the HbA1c level goal at 3 months, 23.6% at 6 months, 20.8% at 9 months, and 20.4% at 12 months. The proportion of patients attaining the goal of HbA1c level < 7.0% at least doubled at different time points after treatment with sitagliptin.

CONCLUSIONS

In this single-hospital retrospective chart analysis, a meaningful clinical improvement in glycemic control before and after sitagliptin treatment commenced, including HbA1c level reduction and the HbA1c goal attainment rate, was observed. The results reflect the actual clinical practice in a large hospital in Taiwan, and supplement data from randomized controlled trials.

Dipeptidyl peptidase-4 inhibitors as a third-line oral antihyperglycaemic agent in patients with type 2 diabetes mellitus: the impact of ethnicity

Aims. The aim of this study is to examine the efficacy of adding a dipeptidyl peptidase-4 (DPP-4) inhibitor to patients with type 2 diabetes inadequately controlled by metformin and sulphonylurea combination treatment. The response of Asian and non-Asian patients to this regimen was also examined. Methods. The medical and computerized records of 80 patients were examined. These patients had baseline HbA1c levels ranging from 7.0 to 12.5% and had a DPP-4 inhibitor add-on therapy for a minimum period of 12 weeks. The primary endpoint was the change in HbA1c level before and after DPP-4 inhibitor treatment. Results. During oral triple therapy, there was a reduction of HbA1c from 8.3% (7.7-8.9) to 7.2% (6.8-7.6) and 26 patients (32.5%) achieved an HbA1c <7%. Poor baseline glycaemic control, lower BMI, and younger age were associated with a better response, but duration of diabetes and gender did not affect outcome. The HbA1c reduction was not different between Asians and non-Asians group [-1.00% (0.6-1.3) vs -0.90% (0.4-1.6)]. Conclusions. DPP-4 inhibitor as a third-line add-on therapy can achieve significant glycaemic improvement in patients with type 2 diabetes inadequately controlled on the combination of metformin and sulphonylurea. The improvement in HbA1c was similar between Asian and non-Asian patients.

Differences in the glucose-lowering efficacy of dipeptidyl peptidase-4 inhibitors between Asians and non-Asians: a systematic review and meta-analysis

AIMS/HYPOTHESIS

The aim of this work was to compare the glucose-lowering efficacy of dipeptidyl peptidase-4 (DPP-4) inhibitors between Asian and non-Asian patients with type 2 diabetes.

METHODS

We searched MEDLINE, EMBASE, LILACS, CENTRAL, ClinicalTrials.gov and conference proceedings. Studies were eligible if they were randomised controlled trials with a treatment duration of at least 12 weeks, compared a DPP-4 inhibitor with a placebo as either monotherapy or oral combination therapy, had information on ethnicity and HbA1c values and were published or described in English. A systematic review and meta-analysis with a meta-regression analysis was conducted.

RESULTS

Among 809 potentially relevant studies, 55 trials were included. A meta-analysis revealed that DPP-4 inhibitors lowered HbA1c to a greater extent in studies with ≥50% Asian participants (weighted mean difference [WMD] -0.92%; 95% CI -1.03, -0.82) than in studies with <50% Asian participants (WMD -0.65%; 95% CI -0.69, -0.60). The between-group difference was -0.26% (95% CI -0.36, -0.17, p < 0.001). The baseline BMI significantly correlated with the HbA1c-lowering efficacy of DPP-4 inhibitors. The RR of achieving the goal of HbA1c <7.0% (53.0 mmol/mol) was higher in studies with ≥50% Asian participants (3.4 [95% CI 2.6, 4.7] vs 1.9 [95% CI 1.8, 2.0]). The fasting plasma glucose-lowering efficacy was higher with monotherapy in the Asian-dominant studies, but the postprandial glucose-lowering efficacy and changes in body weight were comparable between the two groups.

CONCLUSIONS/INTERPRETATION

DPP-4 inhibitors exhibit a better glucose-lowering efficacy in Asians than in other ethnic groups; this requires further investigation to understand the underlying mechanism, particularly in relation to BMI.