Early development of metabolic syndrome in patients subjected to lung transplantation

Metabolic complications in lung transplantation for cystic fibrosis - A case control study

Background

Metabolic complications post-lung transplant are poorly understood and little is known about how these complications differ between patients with or without cystic fibrosis (pwCF and pwoCF). This study compared post-lung transplant outcomes between pwCF and pwoCF relating to survival and incidence of diabetes, dyslipidaemia, hypertension, and renal impairment.

Methods

A retrospective (2004-2017) case-control study involving 90 pwCF and 90 pwoCF (age, sex and year of transplant matched) was conducted. Demographic variables, pre/post-transplant metabolic diseases, blood investigations and medications were extracted. Descriptive statistics were used to describe the cohort. Mann-Whitney U and Chi-squared tests were used to analyse morbidity and mortality data. Regression analyses were used to identity independent variables that impacted clinical outcomes. Kaplan Meier analysis with log-rank testing was used to compare survival.

Results

PwCF were younger, had lower BMIs, and were less likely to have pre-transplant extracorporeal membrane oxygenation (ECMO) use. A total of 37 pwCF and 41 pwoCF died (p = 0.65) during the period of observation with no differences in survival. Adjusting for covariates of age, sex and BMI via multiple logistic regression, CF status was associated with a dramatic increased risk of new-onset diabetes post-transplant (adjusted odds ratio 28.7; 95 % CI, 28.76 to 108.7). No other differences in adjusted risk were found.

Conclusions

As pwCF had a greater adjusted risk of developing new post-transplant diabetes and experienced metabolic complications at similar rates as pwoCF, the findings highlight the need for rigorous monitoring of pwCF for possible metabolic complications post-transplant.

Retrospective analysis on incidence and risk factors of post-transplant diabetes mellitus after lung transplantation and its association with clinical outcomes

BACKGROUND

Post-transplant diabetes mellitus (PTDM) is a common complication after transplantation. We aim to explore potential risk factors of PTDM and its association with outcomes after lung transplantation (LTx).

METHODS

A retrospective study was conducted in 100 patients who underwent LTx at our institution from 2017 to 2021. Patients' information was collected, and genotyping for single nucleotide polymorphisms known to potentially increase the risk of Type 2 DM was performed. Univariate and multivariate analyses were conducted to identify risk factors for PTDM. The primary outcome was the incidence of PTDM. Secondary outcomes were associations between PTDM and clinical outcomes following LTx.

RESULTS

Thirty-nine patients (39.0%) developed PTDM, while 10 patients (25.6%) recovered subsequently. The incidence of PTDM was associated with age > 45 (HR: 2.919, 95% CI [1.021-8.348]), pre-transplant HbA1c > 5.7% (HR: 2.344, 95% CI [1.201-4.573]), KCNJ11 rs5215 (HR: 2.090, 95% CI [1.050-4.162]) and tacrolimus concentration > 8 ng/mL in the first month (HR: 2.090, 95% CI [1.050-4.162]). Patients with PTDM experienced elevated fasting blood glucose levels (FBG) during the first month post-transplantation (p < 0.001), and required a longer duration for FBG to return to normal levels (p < 0.001). However, the presence of PTDM did not significantly impact renal function, incidence of infection episodes, chronic lung allograft dysfunction or mortality following LTx.

CONCLUSION

Advanced age, elevated HbA1c levels, KCNJ11 gene polymorphism, and early exposure to tacrolimus are all significant risk factors for PTDM following LTx. The clinical implications of these factors warrant attention.

Chronic kidney disease after lung transplantation in a changing era

Lung transplant (LTx) physicians are responsible for highly complex post-LTx care, including monitoring of kidney function and responding to kidney function loss. Better survival of the LTx population and changing patient characteristics, including older age and increased comorbidity, result in growing numbers of LTx patients with chronic kidney disease (CKD). CKD after LTx is correlated with worse survival, decreased quality of life and high costs. Challenges lie in different aspects of post-LTx renal care. First, serum creatinine form the basis for estimating renal function, under the assumption that patients have stable muscle mass. Low or changes in muscle mass is frequent in the LTx population and may lead to misclassification of CKD. Second, standardizing post-LTx monitoring of kidney function and renal care might contribute to slow down CKD progression. Third, new treatment options for CKD risk factors, such as diabetes mellitus, proteinuria and heart failure, have entered clinical practice. These new treatments have not been studied in LTx yet but are of interest for future use. In this review we will address the difficult aspects of post-LTx renal care and evaluate new and promising future approaches to slow down CKD progression.

New-onset Obesity After Lung Transplantation: Incidence, Risk Factors, and Clinical Outcomes

BACKGROUND

Lung transplant (LTx) recipients who gain weight after transplantation may experience an upward shift in body mass index (BMI) that places them in the obese category. The incidence, risk factors, and impact on metabolic health and mortality of new-onset obesity have not been documented in the LTx setting.

METHODS

This single-center retrospective study included 564 LTx recipients. Individuals were stratified according to their BMI trajectories from pretransplant evaluation up to 10 y posttransplant. New-onset obesity was defined as a pretransplant BMI <30 kg/m2 and posttransplant BMI >30 kg/m2. The incidence, risk factors, and posttransplant diabetes mellitus, metabolic syndrome, and mortality of recipients with new-onset obesity were compared with those of nonobese (BMI <30 kg/m2, pre/post-LTx), consistently obese (BMI >30 kg/m2, pre/post-LTx), and obese recipients with weight loss (BMI >30 kg/m2 pre-LTx, BMI <30 kg/m2 post-LTx).

RESULTS

We found that 14% of recipients developed obesity after transplantation. Overweight individuals (odds ratio [OR]: 9.01; 95% confidence interval [CI] [4.86-16.69]; P < 0.001) and candidates with chronic obstructive pulmonary disease (OR: 6.93; 95% CI [2.30-20.85]; P = 0.001) and other diagnoses (OR: 4.28; 95% CI [1.22-14.98]; P = 0.023) were at greater risk. Multivariable regression analysis showed that new-onset obesity was associated with a greater risk of metabolic syndrome (hazard ratio: 1.70; 95% CI [1.17-2.46]; P = 0.005), but not of posttransplant diabetes mellitus, than nonobesity. Recipients with new-onset obesity had a survival comparable to that of consistently obese individuals.

CONCLUSIONS

A greater understanding of the multifaceted nature of post-LTx obesity may lead to interventions that are better tailored to the characteristics of these individuals.

Feasibility of a Home-Based Exercise Program for Managing Posttransplant Metabolic Syndrome in Lung and Liver Transplant Recipients: Protocol for a Pilot Randomized Controlled Trial

Background

Posttransplant metabolic syndrome (PTMS) is a common contributor to morbidity and mortality among solid organ transplant recipients in the late posttransplant period (≥1 year). Patients diagnosed with PTMS are at a higher risk of cardiovascular disease and frequently experience decreased physical function and health-related quality of life (HRQL). Studies in the early posttransplant period (<1 year) have shown the benefits of facility-based exercise training on physical function and HRQL, but have not evaluated the effects on metabolic risk factors. It remains unclear whether home-based exercise programs are feasible and can be delivered at a sufficient exercise dose to have effects on PTMS. This protocol outlines the methodology of a randomized controlled trial of a partly supervised home-based exercise program in lung transplant (LTx) and orthotopic liver transplant (OLT) recipients.

Objective

This study aims to evaluate the feasibility (ie, recruitment rate, program adherence, attrition, safety, and participant satisfaction) of a 12-week individualized, home-based aerobic and resistance training program in LTx and OLT recipients initiated 12 to 18 months after transplantation, and to assess estimates of intervention efficacy on metabolic risk factors, exercise self-efficacy, and HRQL.

Methods

In total, 20 LTx and 20 OLT recipients with ≥2 cardiometabolic risk factors at 12 to 18 months after transplantation will be randomized to an intervention (home-based exercise training) or control group. The intervention group will receive an individualized exercise prescription comprising aerobic and resistance training, 3 to 5 times a week for 12 weeks. Participants will meet on a weekly basis (via videoconference) with a qualified exercise professional who will supervise exercise progression, provide support, and support exercise self-efficacy. Participants in both study groups will receive a counseling session on healthy eating with a dietitian at the beginning of the intervention. For the primary aim, feasibility will be assessed through recruitment rate, program adherence, satisfaction, attrition, and safety parameters. Secondary outcomes will be measured at baseline and 12 weeks, including assessments of metabolic risk factors (ie, insulin resistance, abdominal obesity, blood pressure, and cholesterol), HRQL, and exercise self-efficacy. Descriptive statistics will be used to summarize program feasibility and effect estimates (means and 95% CIs) for sample size calculations in future trials.

Results

Enrollment started in July 2021. It is estimated that the study period will be 18 months, with data collection to be completed by December 2022.

Conclusions

A partly supervised home-based, individually tailored exercise program that promotes aerobic and resistance training and exercise self-efficacy may be an important intervention for improving the metabolic profile of LTx and OLT recipients with cardiometabolic risk factors. Thus, characterizing the feasibility and effect estimates of home-based exercise constitutes the first step in developing future clinical trials designed to reduce the high morbidity associated with PTMS.

Trial Registration

ClinicalTrials.gov NCT04965142; https://clinicaltrials.gov/ct2/show/NCT04965142

International Registered Report Identifier (IRRID)

DERR1-10.2196/35700

New onset hypertension after transplantation

It has been reported that up to 90% of organ transplant recipients have suboptimal blood pressure control. Uncontrolled hypertension is a well-known culprit of cardiovascular and overall morbidity and mortality. In addition, rigorous control of hypertension after organ transplantation is a crucial factor in prolonging graft survival. Nevertheless, hypertension after organ transplantation encompasses a broader range of causes than those identified in non-organ transplant patients. Hence, specific management awareness of those factors is mandated. An in-depth understanding of hypertension after organ transplantation remains a debatable issue that necessitates further clarification. This article provides a comprehensive review of the prevalence, risk factors, etiology, complications, prevention, and management of hypertension after organ transplantation.

Metabolic Consequences of Solid Organ Transplantation

Metabolic complications affect over 50% of solid organ transplant recipients. These include posttransplant diabetes, nonalcoholic fatty liver disease, dyslipidemia, and obesity. Preexisting metabolic disease is further exacerbated with immunosuppression and posttransplant weight gain. Patients transition from a state of cachexia induced by end-organ disease to a pro-anabolic state after transplant due to weight gain, sedentary lifestyle, and suboptimal dietary habits in the setting of immunosuppression. Specific immunosuppressants have different metabolic effects, although all the foundation/maintenance immunosuppressants (calcineurin inhibitors, mTOR inhibitors) increase the risk of metabolic disease. In this comprehensive review, we summarize the emerging knowledge of the molecular pathogenesis of these different metabolic complications, and the potential genetic contribution (recipient +/- donor) to these conditions. These metabolic complications impact both graft and patient survival, particularly increasing the risk of cardiovascular and cancer-associated mortality. The current evidence for prevention and therapeutic management of posttransplant metabolic conditions is provided while highlighting gaps for future avenues in translational research.

Sleep-disordered breathing after lung transplantation: An observational cohort study

Data concerning sleep-disordered breathing (SDB) after lung transplantation (LTX) are scarce. This study aims to analyze prevalence, associated factors, and impact on survival of moderate to severe SDB in a large cohort of consecutive LTX patients (n = 219). Patients underwent a diagnostic polysomnography 1 year after LTX. Moderate to severe SDB was present in 57.5% of patients, with the highest prevalence in chronic obstructive pulmonary disease/emphysema (71.1%) and pulmonary fibrosis (65.1%). SDB patients were older, mostly male, and had higher body mass index and neck circumference. Nocturnal diastolic and 24-hour blood pressures were higher in SDB patients. In 45 patients, polysomnography was also performed pre-LTX. Compared to pre-LTX, mean apnea/hypopnea index (AHI) increased significantly after LTX. A significant correlation was seen between lung function parameters and AHI, suggesting a role of decreased caudal traction on the pharynx. Presence of SDB had no impact on mortality or prevalence of chronic lung allograft dysfunction. However, survival was better in continuous positive airway pressure (CPAP) compliant SDB patients compared to SDB patients without CPAP treatment. These findings may be pertinent for systematic screening of SDB after LTX.

Post-transplant diabetes mellitus in patients with solid organ transplants

Solid organ transplantation (SOT) is a life-saving procedure and an established treatment for patients with end-stage organ failure. However, transplantation is also accompanied by associated cardiovascular risk factors, of which post-transplant diabetes mellitus (PTDM) is one of the most important. PTDM develops in 10-20% of patients with kidney transplants and in 20-40% of patients who have undergone other SOT. PTDM increases mortality, which is best documented in patients who have received kidney and heart transplants. PTDM results from predisposing factors (similar to type 2 diabetes mellitus) but also as a result of specific post-transplant risk factors. Although PTDM has many characteristics in common with type 2 diabetes mellitus, the prevention and treatment of the two disorders are often different. Over the past 20 years, the lifespan of patients who have undergone SOT has increased, and PTDM becomes more common over the lifespan of these patients. Accordingly, PTDM becomes an important condition not only to be aware of but also to treat. This Review presents the current knowledge on PTDM in patients receiving kidney, heart, liver and lung transplants. This information is not only for transplant health providers but also for endocrinologists and others who will meet these patients in their clinics.

Prevalence and predictors of diabetes after lung transplantation: a prospective, longitudinal study

OBJECTIVE

To determine incidence and prevalence of diabetes mellitus (DM) after lung transplantation (LTx), identify risk factors for persistent DM after LTx, and determine its effect on survival.

RESEARCH DESIGN AND METHODS

This was a prospective, longitudinal study comparing DM status before and after LTx using oral glucose tolerance tests (OGTTs). DM prevalence and changes in metabolic control over time were determined. Risk factors for persistent DM and survival differences by DM status were assessed.

RESULTS

Between August 2010 and December 2012, 156 patients underwent LTx. DM prevalence after 3, 12, and 24 months was 47%, 44%, and 40%, respectively. A further 20%, 11%, and 7% had impaired glucose tolerance and/or impaired fasting glucose. Incidence of new-onset DM after transplant (NODAT) was 32%, 30%, and 24% after 3, 12, and 24 months. Nonfasting insulin levels and second phase insulin release fell 3 months after transplant (Tx) but returned to baseline by 2 years. The only risk factors for NODAT were 1- and 2-h glucose levels on pre-Tx OGTT (OR 1.73 [95% CI 1.19-2.50], P = 0.004, and 1.84 [1.22-2.77], P = 0.004, respectively). Survival was reduced in patients with DM at study end versus those without (estimated mean 979 days [95% CI 888-1,071] vs. 1,140 days [1,070-1,210], P = 0.023).

CONCLUSIONS

Most patients had dysglycemia during the first year after LTx, and 32% developed NODAT. Hyperglycemia was caused both by β-cell dysfunction and by insulin resistance. Only pre-Tx OGTT glucose levels predicted persistent NODAT. As DM was common and associated with reduced survival, early detection and management of DM in LTx recipients are warranted.