Management Strategies for Posttransplant Diabetes Mellitus after Heart Transplantation: A Review

Propensity matched post-transplant survival in durable CF-axial pump BTT patients with and without diabetes: A UNOS database analysis

Diabetes and post-transplant survival have been linked. However, the impact on post-transplant survival of patients supported on Continuous Flow (CF) axial left ventricular assist devices (LVAD) as a bridge to transplant (BTT) with diabetes has not been widely studied. This study attempts to assess the impact of diabetes type II (DM type II) as a comorbidity influencing survival patterns in the post-cardiac transplant population supported on LVADs and to test if the presence of a pre- transplant durable LVAD acts as an independent risk factor in long-term post-transplant survival. The UNOS database population from 2004 to 2015 was used to construct the cohorts. A total of 21,032 were transplanted during this period. The transplant data were further queried to extract CF-axial flow pumps BTT (HMII-BTT) patients and patients who did not have VAD support before the transplant. A total of 4224 transplant recipients had HMII at the time of transplant, and 13,131 did not have VAD support. Propensity analysis was performed, and 4107 recipients of similar patient characteristics to those in the BTT group were selected for comparison. The patients with a VAD had significantly reduced survival at 2 years post-transplant (p = 0.00514) but this trend did not persist at 5 years (p = 0.0617) and 10 years post-transplant (p = 0.183). Patients with diabetes and a VAD significantly decreased survival at 2 years (p = 0.00204), 5 years (p = 0.00029), and 10 years (p = 0.00193). The presence of a durable LVAD is not an independent risk factor for long-term survival. Diabetes has a longstanding effect on the posttransplant survival of BTT patients.

New-Onset Diabetes Mellitus after Kidney Transplantation

New-Onset Diabetes Mellitus after Transplantation (NODAT) emerges as a prevalent complication post-kidney transplantation, with its incidence influenced by variations in NODAT definitions and follow-up periods. The condition's pathophysiology is marked by impaired insulin sensitivity and β-cell dysfunction. Significant risk factors encompass age, gender, obesity, and genetics, among others, with the use of post-transplant immunosuppressants intensifying the condition. NODAT's significant impact on patient survival and graft durability underscores the need for its prevention, early detection, and treatment. This review addresses the complexities of managing NODAT, including the challenges posed by various immunosuppressive regimens crucial for transplant success yet harmful to glucose metabolism. It discusses management strategies involving adjustments in immunosuppressive protocols, lifestyle modifications, and pharmacological interventions to minimize diabetes risk while maintaining transplant longevity. The importance of early detection and proactive, personalized intervention strategies to modify NODAT's trajectory is also emphasized, advocating for a shift towards more anticipatory post-transplant care.

Early post-transplant hyperglycemia and post-transplant diabetes mellitus following heart transplantation

INTRODUCTION

Heart transplantation is an important treatment for end-stage heart failure. Early post-transplant hyperglycemia (EPTH) and post-transplant diabetes mellitus (PTDM) are common following heart transplantation and are associated with increased morbidity and mortality.

AREAS COVERED

This review summarizes the clinical characteristics, diagnosis, and treatment of EPTH and PTDM in cardiac transplant patients, incorporating findings from non-cardiac solid organ transplant studies where relevant due to limited heart-specific research.

EXPERT OPINION

EPTH following heart transplantation is common yet understudied and is associated with the later development of PTDM. PTDM is associated with adverse outcomes including infection, renal dysfunction, microvascular disease, and an increased risk of re-transplantation and mortality. Risk factors for EPTH include the post-operative immunosuppression regimen, recipient and donor age, body mass index, infections, and chronic inflammation. Early insulin treatment is recommended for EPTH, whereas PTDM management is varied and includes lifestyle modification, anti-glycemic agents, and insulin. Given the emerging evidence on the transplant benefits associated with effective glucose control, and the cardioprotective potential of newer anti-glycemic agents, further focus on the management of EPTH and PTDM within heart transplant recipients is imperative.

Association of fasting blood glucose variability with all-cause mortality in heart transplant recipients

BACKGROUND

Fasting blood glucose (FBG) variability, an emerging marker of glycemic control, has been shown to be related to the risk of cardiovascular events and all-cause mortality in subjects with or without diabetes. However, whether FBG variability is independently associated with a higher all-cause mortality in heart transplant recipients remains unknown.

METHODS

We performed a retrospective cohort study including 373 adult recipients who survived for at least 1 year after heart transplantation with a functioning graft and measured FBG more than three times within first year after transplantation. Multivariable adjusted Cox regression analyses were performed to assess the association between FBG variability and all-cause mortality.

RESULTS

Patients were categorized into three groups according to the coefficient of variation of FBG level: ≤7.0%, 7.0%-13.5%, and >13.5%. During a median follow-up of 44.4 months (interquartile range [IQR], 22.6-63.3 months), 31 (8.3%) participants died. In univariate analyses, FBG variability was associated with an increased all-cause mortality (hazard ratio [HR]: 3.00, 95% confidence interval [CI]: 1.67, 5.38; p < .001). This association remained materially unchanged in the multivariable model adjusted for components of demographics, cardiovascular history and lifestyle, hospital information, immunosuppressive therapy, and post-transplant renal function (HR: 2.75, 95% CI: 1.43, 5.28; p = .004).

CONCLUSIONS

After heart transplantation, high FBG variability is strongly and independently associated with an increased risk of all-cause mortality. Our findings suggest that FBG variability is a novel risk factor and prognostic marker for heart transplantation recipients in outpatient clinic.

Diabetes medication following heart transplantation: a focus on novel cardioprotective therapies-a joint review from endocrinologists and cardiologists

There is accumulating evidence that novel glucose-lowering agents infer potent cardiovascular and renal benefits. Therefore, it is imperative to reassess the management of post-transplant diabetes mellitus and consider the role of newer agents. With improved transplant-related survival and high prevalence of post-transplant diabetes, management of long-term complications such as diabetes are increasingly important. There are limited guidelines to assist in choice of appropriate agents after solid organ transplantation. Traditional therapies including insulin and sulfonylureas may still have a role; however, other agents should be considered prior. The evidence of novel glucose-lowering agents in post-transplant care is limited, and most studies have focused on kidney transplant recipients. While there are some parallels between renal and cardiac transplant recipients, the potential cardiovascular benefits, particularly on cardiac fibrosis are unique to cardiac transplantation. The treatment of diabetes, with a focus on additional cardiac and renal benefits, needs to be brought to the forefront of post-transplant care with incorporation of recent evidence outside of transplantation. The role for novel glucose-lowering agents in cardiac transplant recipients will be explored, with a summary of available evidence.

Post-Transplant Diabetes: Prevalence, Risk, and Management Challenges

The prevalence of diabetes and diabetic nephropathy is increasing, especially in middle eastern countries. Many patients reach end-stage renal disease and either start dialysis or consider preemptive transplantation. Even a higher number of patients develop post-transplant diabetes, which imposes an even higher risk on graft survival and outcomes post-transplantation. Recently, in the UAE, a renal transplant service has been initiated. Because the population is considered at high risk for post-transplant diabetes, we wrote this review article to discuss the prevalence, risk factors, diagnostic criteria, and management, including lifestyle interventions, manipulation of immunosuppressant agents, and suggested algorithms for the use of oral hypoglycemic agents used in the management of post-transplantation diabetes mellitus. We also discussed the specific indications for each of the oral hypoglycemic agents.

Institutional Experience With New Antidiabetic Drugs in Kidney Transplant

BACKGROUND

The recent introduction of new antidiabetic drugs, analogs of glucagon-like peptide-1 (GLP-1) and sodium-glucose cotransporter 2 inhibitors, has shown excellent results in the management of patients with diabetes with chronic kidney disease. However, documented results of these medications in the population that has undergone kidney transplant are sparse. We report our institutional experience with them, including occurrence of side effects and possible interactions with immunosuppressive medications.

METHODS

A retrospective analysis of 15 patients (10 with diabetes and 5 without diabetes but with obesity) managed with these medications was carried out in the kidney transplant unit of Hospital Doctor Peset during the year 2019. Data acquired at baseline and 3, 6, and 12 months were analyzed.

RESULTS

The median hemoglobin A1c at baseline was 6.7 (interquartile range [IQR] = 5.8-8.2) and at 12 months it was 6 (IQR = 5.3-8.1, P = .96). The mean weight difference at 12 months was a loss of 7.2 ± 6 kg; median body mass index at baseline was 31.2 kg/m² (IQR = 29.7-35.5) and 29.5 kg/m² (IQR = 27.6-31.6, P = .01) at 12 months. In addition to weight loss, a reduction in insulin and oral antidiabetic drug requirements was observed. No significant changes were detected in serum creatinine or proteinuria values and the immunosuppressant levels remained stable. No acute rejection episodes were observed.

CONCLUSION

Based on our experience, the new antidiabetic drugs are safe, with no significant changes in renal function or immunosuppressant levels or clinically important adverse effects.

Impact of diabetes mellitus on clinical outcomes after heart transplantation

PURPOSE

Diabetes mellitus (DM) is common among recipients of heart transplantation (HTx) but its impact on clinical outcomes is unclear. We evaluated the associations between pretransplant DM and posttransplant DM (PTDM) and outcomes among adults receiving HTx at a single center.

METHODS

We performed a retrospective study (range 01/2008 - 07/2018), n = 244. The primary outcome was survival; secondary outcomes included acute rejection, cardiac allograft vasculopathy, infection requiring hospitalization, macrovascular events, and dialysis initiation post-transplant. Comparisons were performed using Kaplan-Meier and multivariable Cox regression analyses.

RESULTS

Pretransplant DM was present in 75 (30.7%) patients and was associated with a higher risk for infection requiring hospitalization (p<0.05), but not with survival or other outcomes. Among the 144 patients without pretransplant DM surviving to one year, 29 (20.1%) were diagnosed with PTDM at the 1-year follow-up. After multivariable adjustment, PTDM diagnosis at 1-year remained associated with worse subsequent survival (hazard ratio 2.72, 95% confidence interval 1.03-7.16). Predictors of PTDM at 1-year included cytomegalovirus seropositivity and higher prednisone dose (>5mg/day) at 1-year follow-up.

CONCLUSIONS

Compared to HTx recipients without baseline DM, those with baseline DM have a higher risk for infections requiring hospitalization, and those who develop DM after HTx have worse survival. This article is protected by copyright. All rights reserved.

Chances and risks of sodium-glucose cotransporter 2 inhibitors in solid organ transplantation: A review of literatures

Solid organ transplantation offers life-saving treatment for patients with end-organ dysfunction. Patient survival and quality of life have improved over the past few decades as a result of pharmacological development, expansion of the donor pool, technological advances and standardization of practices related to transplantation. Still, transplantation is associated with cardiovascular complications, of which post-transplant diabetes mellitus (PTDM) is one of the most important. PTDM increases mortality, which is best documented in patients who have received kidney and heart transplants. PTDM results from traditional risk factors seen in patients with type 2 diabetes mellitus, but also from specific post-transplant risk factors such as metabolic side effects of immunosuppressive drugs, post-transplant viral infections and hypomagnesemia. Oral hypoglycaemic agents are the first choice for the treatment of type 2 diabetes mellitus in non-transplanted patients. However, the evidence on the safety and efficacy of oral hypoglycaemic agents in transplant recipients is limited. The favourable risk/benefit ratio, which is suggested by large-scale and long-term studies on new glucose-lowering drug classes such as glucagon-like peptide 1 receptor agonists and sodium-glucose cotransporter 2 inhibitors, makes studies warranted to assess the potential role of these agents in the management of PTDM.

Diabetes and Cardiovascular Risk in Renal Transplant Patients

End-stage kidney disease (ESKD) is a main public health problem, the prevalence of which is continuously increasing worldwide. Due to adverse effects of renal replacement therapies, kidney transplantation seems to be the optimal form of therapy with significantly improved survival, quality of life and diminished overall costs compared with dialysis. However, post-transplant patients frequently suffer from post-transplant diabetes mellitus (PTDM) which an important risk factor for cardiovascular and cardiovascular-related deaths after transplantation. The management of post-transplant diabetes resembles that of diabetes in the general population as it is based on strict glycemic control as well as screening and treatment of common complications. Lifestyle interventions accompanied by the tailoring of immunosuppressive regimen may be of key importance to mitigate PTDM-associated complications in kidney transplant patients. More transplant-specific approach can include the exchange of tacrolimus with an alternative immunosuppressant (cyclosporine or mammalian target of rapamycin (mTOR) inhibitor), the decrease or cessation of corticosteroid therapy and caution in the prescribing of diuretics since they are independently connected with post-transplant diabetes. Early identification of high-risk patients for cardiovascular diseases enables timely introduction of appropriate therapeutic strategy and results in higher survival rates for patients with a transplanted kidney.

Effects of GLP-1 receptor agonists and SGLT-2 inhibitors in heart transplant patients with type 2 diabetes: Initial report from a cardiometabolic center of excellence

Type 2 diabetes mellitus (T2D) is a common comorbidity among patients who have undergone heart transplantation. Recently two classes of glucose-lowering medications (sodium-glucose cotransporter type-2 inhibitors [SGLT-2Is] and glucagon-like-peptide-1 receptor agonists [GLP-1RAs]), have been shown to significantly improve cardiovascular outcomes. There is a paucity of data regarding their use in immunosuppressed patients, with many studies specifically excluding this population. We retrospectively evaluated the safety and efficacy of GLP-1RAs and SGLT-2Is in patients who had undergone orthotopic heart transplant at a high-volume center. Among 21 patients, we found significant weight loss, reductions in insulin use, hemoglobin A1c, and low-density lipoprotein-cholesterol. Moreover, both SGLT-2Is and GLP-1RAs were well tolerated with no adverse events leading to discontinuation of either therapy. While larger studies of patients after solid organ transplant are needed, this small hypothesis-generating study demonstrates that SGLT-2Is and GLP-1RAs appear safe and effective therapies among patients with T2D after heart transplant.

Current Pharmacological Intervention and Medical Management for Diabetic Kidney Transplant Recipients

Hyperglycemia after kidney transplantation is common in both diabetic and non-diabetic patients. Both pretransplant and post-transplant diabetes mellitus are associated with increased kidney allograft failure and mortality. Glucose management may be challenging for kidney transplant recipients. The pathophysiology and pattern of hyperglycemia in patients following kidney transplantation is different from those with type 2 diabetes mellitus. In patients with pre-existing and post-transplant diabetes mellitus, there is limited data on the management of hyperglycemia after kidney transplantation. The following article discusses the nomenclature and diagnosis of pre- and post-transplant diabetes mellitus, the impact of transplant-related hyperglycemia on patient and kidney allograft outcomes, risk factors and potential pathogenic mechanisms of hyperglycemia after kidney transplantation, glucose management before and after transplantation, and modalities for prevention of post-transplant diabetes mellitus.

Post-transplant diabetes mellitus: incidence, predicting factors and outcomes

PURPOSE

To identify predictors and evaluate outcomes of posttransplant diabetes mellitus (PTDM) and to investigate the effect of treatment modalities on outcomes.

METHODS

The database of a tertiary medical center was searched for all adult patients without prior diabetes who underwent lung, liver, or heart transplantation between January 1, 2012 and June 30, 2018. Patients in whom PTDM (defined as HbA1C ≥ 6.5% at least 3 months post transplantation) developed during follow-up (mean 3.32 years) were identified. Risk factors for PTDM, determined by regression analysis and clinical outcomes [all-cause mortality, severe infections, graft loss, and major adverse cardiovascular events (MACE)], were compared between those who developed PTDM and those who did not; in the former, insulin-based therapy was compared with non-insulin regimen.

RESULTS

The cohort included 281 transplant recipients: 158 lung, 109 liver, and 14 heart. PTDM was diagnosed in 60 (21.35%) patients at a mean of 11.3 ± 12.89 months post transplantation. The only significant independent risk factor for PTDM was age (HR 1.028, 95% CI = 1.002-1.054, P = 0.0314). PTDM was associated with higher rates of severe infections (HR 2.565, 95% CI = 1.626-4.050, P < 0.0001), MACE (HR 1.856, 95% CI = 1.013-3.401, P = 0.0454) and death (HR 1.840, 95% CI = 1.024-3.304, P = 0.0413). Recipients treated with insulin-based regimens had a higher risk of severe infections (HR 2.579, 95% CI = 1.640-4.055, P < 0.0001), MACE (1.925, 95% CI = 1.074-3.451, P = 0.0278) and death (HR 1.960, 95% CI = 1.071-3.586, P = 0.0291).

CONCLUSIONS

PTDM is associated with increased mortality and poor outcomes in lung, liver, and heart transplant recipients. Early identification and aggressive treatment of PTDM and its associated cardiometabolic risk factors may improve outcomes.

The pharmaceutical management of cardiac allograft vasculopathy after heart transplantation

INTRODUCTION

Cardiac allograft vasculopathy (CAV) is a major limitation to long-term survival after heart transplantation. Its peculiar pathophysiology involves multifactorial pathways including immune-mediated and metabolic risk factors, which are associated with the development of specific pathological lesions. The often diffuse and chronic nature of the disease reduces the effectiveness of revascularization procedures, and pharmacological prevention of the disease is the sole therapeutic approach with some proven efficacy.

AREAS COVERED

In this article, after briefly outlining the risk factors for CAV, the authors revise the potential pharmacological approaches that may reduce the burden of CAV. While several therapies have shown convincing efficacy in terms of CAV prevention diagnosed by coronary imaging, very few have been reported to improve prognosis with any meaningful level of evidence.

EXPERT OPINION

The authors believe that a customizable approach is necessary for clinical practice given the currently available evidence. Furthermore, it is important, in the future, to address the glaring therapeutic gap of an effective treatment against donor-specific antibodies, whose effect on endothelial injury is currently one of the major mechanisms of CAV development and for which no pharmacological treatment is currently available.

Prevention of cardiac allograft vasculopathy - A new possible indication for SGLT-2 inhibitors?

One of the main risk factors influencing patient survival after heart transplantation is cardiac allograft vasculopathy, the leading cause of death after the first year of transplantation. It is an entity of multifactorial origin including both humoral and cellular alloimmune responses as well as immunologic-independent factors such as graft injury, ischaemia-reperfusion injury, oxidative stress, cytomegalovirus infection, hyperlipidaemia, diabetes mellitus and hypertension. A fundamental characteristic of cardiac allograft vasculopathy is vascular remodelling, initially driven by the injury and apoptosis of endothelial cells, then by the migration of smooth muscle cells leading to intimal thickening and ultimately allograft vessel occlusion. Since cardiac allograft vasculopathy occurs within the first year of transplantation, prevention strategies should be implemented early. The disease could be partially prevented with overall cardiovascular risk reduction, mainly by controlling diabetes, hyperlipidemia and hypertension that can be related to the recipient but also induced or augmented by immunosuppressive drugs used. Current therapeutic options are only partially effective in postponing the development of vascular lesions. Diabetes is an important issue in the management of patients following cardiac transplantation. Although it is highly prevalent among heart transplant recipients (23% at 1 year increasing to 37% at 5 years after the procedure), no specific therapeutic protocols have been recommended yet. Sodium-glucose cotransporter-2 (SGLT-2) inhibitors are a novel class of antidiabetic drugs that produce glycosuric and natriuretic effects by inhibiting glucose and sodium reabsorption from the renal proximal tubules and have already shown benefits in cardiovascular outcome trials. Our hypothesis is that SGLT-2 inhibitors could prevent or delay the development of cardiac allograft vasculopathy targeting various mechanisms underpinning its pathogenesis due to their antidiabetic, antihypertensive, anti-inflammatory, antifibrotic, antioxidative and antiapoptotic effects, as well as through amelioration of endothelial dysfunction, ischaemia-reperfusion injury and modification of neurohumoral system. All the segments of the proposed theory that could interfere with evolution of vasculopathy are discussed separately within the main text. The implications for the science if the hypothesis were to be confirmed are as follows: prolongation of lifespan in heart transplant patients with diabetes, reduction of polypragmasia in posttransplant patients while targeting several mechanisms with one drug, and the possibility of spreading the indications even to patients without diabetes.

Metformin therapy in patients with diabetes mellitus is associated with a reduced risk of vasculopathy and cardiovascular mortality after heart transplantation

Background

Cardiac allograft vasculopathy (CAV) is a major cause of morbidity and mortality following heart transplantation (HT). Reduced cardiovascular mortality and morbidity have been reported in non-HT patients treated with metformin. Given the high prevalence of type 2 diabetes mellitus (T2DM) in HT patients, we investigated the association between metformin therapy and cardiovascular outcomes after HT.

Methods

The study population comprised 103 DM patients who had undergone HT between 1994 and 2018 and were prospectively followed-up. We excluded from the study patients with type 1 diabetes mellitus. Fifty-five HT patients (53%) in the cohort were treated with metformin. Clinical data were recorded on prospectively designed forms. The primary outcomes included CAV, survival, and the combined end-point of CAV or cardiovascular mortality.

Results

Kaplan–Meier survival analysis showed that the CAV rate at 20 years of follow-up was lower in DM patients treated with metformin than in those who were not (30 vs. 65%; log-rank p = 0.044). Similarly, the combined risk of CAV or cardiovascular mortality was lower in the metformin-treated patients than in those not receiving metformin (32 vs. 68%; log rank p = 0.01). Consistently, multivariate analysis adjusted for age and comorbidities showed that metformin therapy was independently associated with a significant 90% reduction (95% confidence interval 0.02–0.46, p = 0.003) in the risk for the development of CAV, and a 91% reduction (95% confidence interval 0.02–0.42; p = 0.003) in the risk for CAV or cardiovascular mortality.

Conclusions

In diabetic HT patients, metformin therapy is independently associated with a significant reduction in the long-term risk for CAV and the combined end-point of CAV or cardiovascular mortality after HT.

The change of immunosuppressive regimen from calcineurin inhibitors to mammalian target of rapamycin (mTOR) inhibitors and its effect on malignancy following heart transplantation

Malignancy is a significant cause of mortality after organ transplantation. There is an increased rate of malignancy following heart transplantation (HTx) compared to the general population and other organ transplant recipients. Post-HTx patients with a history of malignancy are also at a higher risk of developing new malignancies or exacerbation of their existing malignancies. Mammalian target of Rapamycin inhibitors (mTORIs) are newly introduced immunosuppressive drugs with a unique mechanism of action. By changing the immunosuppressive regimen from classic drugs, especially calcineurin inhibitors (CNIs) to mTORIs, the rate of developing de novo malignancies and the relapse of former malignancies is significantly reduced. However, issues like allograft function, total surveillance of patients, and post-transplantation complications should be considered during the conversion of drug regimens utilizing CNIs to drug regimens employing mTORIs. We reviewed different post-heart transplant maintenance immunosuppressive regimens and their effect on post-HTx malignancies with a focus on mTORIs, compared safety against effectiveness, and gathered conclusions based on our review of the literature, which may lead clinicians to make a better evidence-based decision regarding post-HTx maintenance immunosuppressive drug regimens. Overall, CNI to mTORI conversion in post-HTx maintenance immunosuppressive drug regimens was associated with a reduced rate of developing malignancy in post-HTx patients. Furthermore, nephrotoxicity decreased significantly while using mTORIs in combination with lower doses of CNIs and the rejection rate was equivalent to CNI-only regimens. In conclusion, mTORI-based maintenance immunosuppressive drug regimens seem to be safe and beneficial when considering efficacy vs. adverse effects, and all-cause mortality rates are significantly lower in patients switched to mTORIs when compared to CNI recipients.