Body mass index and its effect on outcome in children after lung transplantation

Nutritional status in the era of highly effective CFTR modulators

Advances in cystic fibrosis (CF) diagnostics and therapeutics have led to improved health and longevity, including increased body weight and decreased malnutrition in people with CF. Highly effective CFTR modulator therapies (HEMT) are associated with increased weight through a variety of mechanisms, accelerating trends of overweight and obesity in the CF population. Higher body mass index (BMI) is associated with improved pulmonary function in CF, yet the incremental improvement at overweight and obese BMIs is not clear. Improvements in pulmonary health with increasing BMI are largely driven by increases in fat-free mass (FFM), and impact of HEMT on FFM is uncertain. While trends toward higher weight and BMI are generally seen as favorable in CF, the increased prevalence of overweight and obesity has raised concern for potential risk of traditional age- and obesity-related comorbidities. Such comorbidities, including impaired glucose tolerance, hypertension, cardiac disease, hyperlipidemia, fatty liver, colon cancer, and obstructive sleep apnea, may occur on top of pre-existing CF-related comorbidities. CF nutrition recommendations are evolving in the post-modulator era to more individualized approaches, in contrast to prior blanket high-fat, high-calorie prescriptions for all. Ultimately, it will be essential to redefine goals for optimal weight and nutritional status to allow for holistic health and aging in people with CF.

Interstitial lung disease as an indication for pediatric lung transplant

Interstitial lung disease can be an indication for lung transplant at any age, but it is a particularly common indication for lung transplant in infants. Nevertheless, not all interstitial lung diseases will lead to lung transplant in childhood. Genetic testing has aided the identification of these diseases in children. In severely affected patients, however, definitive diagnosis is not always necessary to consider referral to a transplant center. At experienced transplant centers, a multidisciplinary team educates patient families and aids in the transplant evaluation of children with interstitial lung disease. Children who have undergone transplant require lifetime immunosuppression and close surveillance, but can enjoy good quality of life for years following surgery.

ESPEN-ESPGHAN-ECFS guideline on nutrition care for cystic fibrosis

BACKGROUND

Nutritional status is paramount in Cystic Fibrosis (CF) and is directly correlated with morbidity and mortality. The first ESPEN-ESPGHAN-ECFS guidelines on nutrition care for infants, children, and adults with CF were published in 2016. An update to these guidelines is presented.

METHODS

The study was developed by an international multidisciplinary working group in accordance with officially accepted standards. Literature since 2016 was reviewed, PICO questions were discussed and the GRADE system was utilized. Statements were discussed and submitted for on-line voting by the Working Group and by all ESPEN members.

RESULTS

The Working Group updated the nutritional guidelines including assessment and management at all ages. Supplementation of vitamins and pancreatic enzymes remains largely the same. There are expanded chapters on pregnancy, CF-related liver disease, and CF-related diabetes, bone disease, nutritional and mineral supplements, and probiotics. There are new chapters on nutrition with highly effective modulator therapies and nutrition after organ transplantation.

Body mass index percentage and survival in pediatric patients listed for lung transplantation: A modern-era multi-institutional analysis

BACKGROUND

Prior studies suggest that being underweight by body mass index percentiles (BMI%) or thinness grade did not affect post-transplant survival in pediatric lung transplant (LTx) recipients regardless of cystic fibrosis (CF) or non-CF diagnosis. Graft and overall survival from the time of listing was instead evaluated based on listing BMI%, the current standard of practice for BMI definitions in pediatrics, to ascertain the impact of a "severely low" subcategory.

METHODS

The UNOS registry was queried for children listed for LTx (aged 2 to <18 years) from January 1986 to March 2020. BMI% at listing and transplant were calculated per CDC guidelines according to age in years, sex, and reported BMI%. Patients were divided by listing BMI%: severely low (<3rd), low (3-<5th), normal (5-<85th), overweight (85-<95th), and obese (≥95th). Kaplan-Meier curves were generated to assess differences in overall survival since listing based on BMI% classes. Cox proportional-hazards models were developed to assess risk factors for overall and graft survival, including listing BMI%, transplant listing era (≥2005), and listing age, by reporting hazard ratios (HR).

RESULTS

Listing BMI% was calculable for 1,876 patients. The proportion of patients with CF differed significantly between BMI% groups (p < 0.001). Patients listed with a non-CF diagnosis comprised 34% of those in the severely low category, and 88% of those listed with an obese BMI%. Compared to patients with a normal listing BMI%, the cohort with severely low BMI% had worse overall survival regardless of LTx (p = 0.009) and graft survival (p = 0.034). Compared to patients with a low BMI%, those with a severely low BMI% had significantly poorer graft survival as well (p = 0.040). Mean graft survival was not significantly different between groups that remained at listing BMI% vs those that improved in category despite an overall small sample size. Independent predictors of poorer survival from the time of listing include severely low vs low-normal BMI% (HR = 1.20) and listing age (HR = 1.02).

CONCLUSION

The proportion of children listed at severely low BMI% has steadily decreased with time, yet pediatric LTx candidates listed with a severely low BMI% had poorer graft and overall survival compared to those of normal BMI%. Severely low listing BMI% was an independent prognostic factor for higher mortality risk from the time of placement on the waitlist. BMI% may be a modifiable target for improving survival regardless of transplantation.

Lung transplantation outcomes in underweight recipients: A single center experience

Background

Current guidelines recommend a body mass index (BMI) of 16 kg/m² as the minimum threshold for lung transplantation, despite mixed evidence on outcomes in underweight patients. The current study aimed to describe survival outcomes of underweight patients who underwent lung transplantation at a single center.

Methods

This retrospective observational study included adult lung transplant recipients who underwent transplantation for the first time between March 2010 and March 2022 at King Faisal Specialist Hospital and Research Center and excluded patients with obesity. We defined an underweight status as a BMI <17 kg/m².

Results

Forty-eight of the 202 lung transplant recipients were underweight at the time of surgery. The underweight patients had similar lengths of hospital (p = 0.53) and intensive care unit (p = 0.81) stays compared to other patients. Thirty-three percent of underweight patients had died within 5-year follow-up, compared to 34% of patients who were not underweight. There was no significant difference in mortality risk between underweight patients and patients with normal BMIs in our multivariable Cox regression model (adjusted HR 1.57, 95%CI: 0.77-3.20, p = 0.21). Exploratory analyses revealed that a pre-transplant BMI <13 kg/m² was associated with a trend towards increased 5-year mortality (adjusted HR 4.00, 95%CI: 0.87-18.35, p = 0.07).

Conclusions

Our findings suggest that patients with BMIs of 13-17 kg/m² may be candidates for lung transplantation. Large multi-center cohort studies are needed to confirm the lower BMI limit for safely transplanting patients.

First in Poland Simultaneous Liver-Lung Transplantation With Liver-First Approach for Recipient Due to Cystic Fibrosis: A Case Report

Cystic fibrosis is an autosomal progressive disease affecting the lung, pancreas, and liver. Some patients develop end-stage respiratory and liver failure. For such patients, combined lung-liver transplantation remains the only therapeutic option. In this article we present the first simultaneous lung-liver transplantation in Poland, as well as in Central and Eastern Europe, with detailed clinical history, surgical aspects, and postoperative course.

Association of obesity with mortality and clinical outcomes in children and adolescents with transplantation: A systematic review and meta-analysis

Obesity might be associated with mortality and clinical outcomes following transplantation; however, the direction of this relationship has not been well-recognized in youth. The aim of this systematic review and meta-analysis was to investigate the association of obesity with post-transplant mortality and clinical outcomes in children and adolescents. Following a systematic search of observational studies published by December 2018 in PubMed, Scopus, Embase, and Cochrane library, 15 articles with total sample size of 50,498 patients were included in the meta-analysis. The main outcome was mortality and secondary outcomes included acute graft versus host disease (GVHD), acute rejection, and overall graft loss. The pooled data analyses showed significantly higher odds of long term mortality (OR 1.30, 95% CI 1.15-1.48, P < 0.001, I² = 50.3%), short term mortality (OR 1.79, 95% CI 1.19-2.70, P = 0.005, I² = 59.6%), and acute GVHD (OR 2.13, 95% CI 1.5-3.02, P < 0.001, I² = 1.7%) in children with obesity. There were no significant differences between patients with and without obesity in terms of acute rejection (OR 1.07, 95% CI 0.98-1.16, P = 0.132, I² = 7.5%) or overall graft loss (OR 1.04, 95% CI 0.84-1.28, P = 0.740, I² = 51.6%). This systematic review and meta-analysis has stated higher post-transplant risk of short and long term mortality and higher risk of acute GVHD in children with obesity compared to those without obesity. Future clinical trials are required to investigate the effect of pre-transplant weight management on post-transplant outcomes to provide insights into the clinical application of these findings. This may in turn lead to establish guidelines for the management of childhood obesity in transplantations.

Cystic fibrosis foundation consensus statements for the care of cystic fibrosis lung transplant recipients

Cystic fibrosis (CF) is the indication for transplantation in approximately 15% of recipients worldwide, and Cystic Fibrosis Lung Transplant Recipients (CFLTRs) have excellent long-term outcomes. Yet, CFLTRs have unique comorbidities that require specialized care. The objective of this document is to provide recommendations to CF and lung transplant clinicians for the management of perioperative and underlying comorbidities of CFLTRs and the impact of transplantation on these comorbidities. The Cystic Fibrosis Foundation (CFF) organized a multidisciplinary committee to develop CF Lung Transplant Clinical Care Recommendations. Three workgroups were formed to develop focused questions. Following a literature search, consensus recommendations were developed by the committee members based on literature review, committee experience and iterative revisions, and in response to public comment. The committee formulated 32 recommendation statements in the topics related to infectious disease, endocrine, gastroenterology, pharmacology, mental health and family planning. Broadly, the committee recommends close coordination of care between the lung transplant team, the cystic fibrosis care center, and specialists in other disciplines with experience in the care of CF and lung transplant recipients. These consensus statements will help lung transplant providers care for CFLTRs in order to improve post-transplant outcomes in this population.

Timing it right: the challenge of recipient selection for lung transplantation

Selection criteria for the referral and potential listing of patients for lung transplantation (LTx) have changed considerably over the last three decades but one key maxim prevails, the ultimate focus is to increase longevity and quality of life by careful utilization of a rare and precious resource, the donor organs. In this article, we review how the changes have developed and the outcomes of those changes, highlighting the impact of the lung allocation score (LAS) system. Major diseases, including interstitial lung disease (ILD), chronic obstructive pulmonary disease and pulmonary hypertension are considered in detail as well as the concept of retransplantation where appropriate. Results from bridging to LTx using extracorporeal membrane oxygenation (ECMO) are discussed and other potential contraindications evaluated such as advanced age, frailty and resistant infections. Given the multiplicity of risk factors it is a credit to those working in the field that such excellent and improving results are obtained with an ongoing dedication to achieving best practice.

The outcomes of 80 lung transplants in a single center from Saudi Arabia

BACKGROUND

Lung transplantation has become a standard of care for a select group of patients with advanced lung diseases. Lung transplantation has undergone rapid growth in the last few years in Saudi Arabia.

OBJECTIVE

Describe five years of experience with lung transplantation.

DESIGN

Retrospective, descriptive.

SETTINGS

Major tertiary care hospital.

PATIENTS

All patients who underwent lung transplant surgery between 2010 to 2015.

MAIN OUTCOME MEASURES

Indications for lung transplant demographics, body mass index, blood group, type of transplant surgery, morbidity rate using the Clavien-Dindo classification, rate of early- and late-onset bronchiolitis obliterans syndrome (BOS), bronchiolitis obliterans-free survival, 30- and 90-day mortality rate, and survival (30 days, 90 days, 1-year, 3-years and 5-years) for lung transplant recipients. The duration of mechanical ventilation, colonization by bacteria and need for lung volume reduction surgery for lung donors.

SAMPLE SIZE

80, 45% women and 55% men.

RESULTS

The most common indication for lung transplant in Saudi Arabia is pulmonary fibrosis (45%), followed by non-cystic fibrosis bronchiectasis (25%) and cystic fibrosis-related bronchiectasis (20%). Only 45% of our lung transplant recipients had a normal BMI (18-28 kg/m2). The most frequent blood group was A (40%), followed by blood group O (32.5%). Most (85%) lung transplants were bilateral while 15% were single lung transplants. Postoperative complications developed in 64 patients, 34 (42.5%) had minor grade 1 complications, while 13 (16.5%) had severe complications leading to death (grade V). Early onset BOS developed in 6 (7.5%) patients while 16 (20%) had late onset BOS. The BOS-free survival rate was 72.5%. The mean duration of mechanical ventilation in lung donors was 9 days and most were infected by bacteria. The majority of recipients required lung volume reduction. The 30-day mortality rate was 12.5% and the 90-day mortality rate was 17.5%. Survival rates at our center were 87.5% at 30 days, 82.5% at 90 days, 81.2% at 1 year, 67.9% at 2 years and 62.1% at 5 years.

CONCLUSIONS

Lung transplantation has become an invaluable approach for the treatment of end-stage respiratory disease. Our 5-year experience has shown exciting promises for lung transplantation in Saudi Arabia.

LIMITATIONS

Retrospective design, single center experience.

CONFLICT OF INTEREST

None.

Pre-transplant weight loss and clinical outcomes after lung transplantation

BACKGROUND

Patients with greater adiposity before lung transplantation are at an increased risk for worse post-transplant outcomes. Few studies have addressed whether pre-transplant weight loss mitigates this risk. In this study we examined the association between pre-transplant weight loss and post-transplant clinical outcomes.

METHODS

We conducted a retrospective cohort study of patients who received a lung transplant at the Duke University Hospital from May 1, 2005 to April 30, 2015. The sample included adult transplant recipients with restrictive, obstructive, and vascular diseases. Cox proportional hazards models were used to examine mortality and chronic lung allograft dysfunction (CLAD)-free survival, and negative binomial regression analyses were used to examine length of stay (LOS). Weight loss was assessed from change in body mass index (BMI).

RESULTS

The cohort consisted of 810 patients. Initially, 403 (50%) were overweight and 109 (13%) were obese by BMI criteria. Greater pre-transplant weight loss was associated with dose-response improvements in survival (hazard ratio [HR] 0.83 [0.72 to 0.97], p = 0.018), with modest (0% to 3%, HR 0.91), moderate (7% to 10%, HR 0.83), and high (>15%, HR 0.71) levels of weight loss conferring longer survival, independent of initial weight (p = 0.533 for interaction). Weight loss was also associated with improved CLAD-free survival (HR 0.84 [0.71 to 0.99], p = 0.034) and shorter LOS (b = ‒0.17, p < 0.001).

CONCLUSIONS

Weight loss before transplantation was associated with improved short- and long-term clinical outcomes, independent of initial weight. Survival improved proportionally to percentage of weight lost. The mechanisms by which weight loss improve clinical outcomes warrant further exploration.

Diabetes mellitus in pediatric solid organ recipients without and with cystic fibrosis: An analysis from the German-Austrian diabetes database (Diabetes Patienten Verlaufsdokumentation)

INTRODUCTION

Posttransplantation diabetes mellitus (PTDM) increases the risk of cardiovascular disease, graft loss, and decreased survival. Follow-up treatment after solid organ transplantation (SOT) needs to focus on, inter alia, maintaining balanced glucose metabolism. This study aimed to ascertain the prevalence of PTDM and describe patient characteristics in the large DPV (Diabetes Patienten Verlaufsdokumentation) pediatric diabetes database.

METHODS

DPV data of 71 902 patients from the January 01, 1995 to January 04, 2015 period were analyzed for patients with and without cystic fibrosis (CF) after SOT (kidney, liver, heart, and lung). Multivariable analysis served to assess differences between SOT patient groups at risk for developing diabetes.

RESULTS

Out of 109 SOT patients, 51 had CF; 72.5% received steroids and 62% were additionally given tacrolimus. PTDM developed in 45% of CF patients and 12% of non-CF patients. SOT patients were older at diabetes onset (mean age, 12.50 ± 3.98 years), shorter (height z-score, -1.67 ± 1.25), and lighter (weight z-score, -1.59 ± 1.57) than non-SOT diabetes patients (P < 0.01). With transplantation, glycated hemoglobin (HbA1c) was significantly lower and treatment for hypertension and dyslipidemia was increased. Among SOT patients, weight and body mass index (BMI) z-scores were significantly lower in patients with CF-related diabetes (P < 0.05).

CONCLUSIONS

SOT was present in 6.6% of children with diabetes, and this might aggravate the risk of cardiovascular disease in populations with already increased rates of hypertension and dyslipidemia. Dystrophy and short stature were also present, particularly in transplant recipients with CF and diabetes. Comorbidities and long-term consequences call for multidisciplinary collaboration.

The Impact of Waiting List BMI Changes on the Short-term Outcomes of Lung Transplantation

BACKGROUND

Obesity and underweight are associated with a higher postlung transplantation (LTx) mortality. This study aims to assess the impact of the changes in body mass index (BMI) during the waiting period for LTx on early postoperative outcomes.

METHODS

Medical records of 502 consecutive cases of LTx performed at our institution between 1999 and 2015 were reviewed. Patients were stratified per change in BMI category between pre-LTx assessment (candidate BMI) and transplant BMI as follows: A-candidate BMI, less than 18.5 or 18.5 to 29.9 and transplant BMI, less than 18.5; B-candidate BMI, less than 18.5 and transplant BMI, 18.5 to 29.9; C-candidate BMI, 18.5 to 29.9 and transplant BMI, 18.5 to 29.9; D-candidate BMI, 30 or greater and transplant BMI, 18.5 to 29.9; and E-candidate BMI, 30 or greater or 18.5 to 29.9 and transplant BMI, 30 or greater. Our primary outcome was in-hospital mortality and secondary outcomes were length of mechanical ventilation, intensive care unit length of stay (LOS), hospital LOS and postoperative complications.

RESULTS

BMI variation during the waiting time was common, as 1/3 of patients experienced a change in BMI category. Length of mechanical ventilation (21 days vs 9 days; P = 0.018), intensive care unit LOS (26 days vs 15 days; P = 0.035), and rates of surgical complications (76% vs 44%; P = 0.018) were significantly worse in patients of group E versus group D. Obese candidates who failed to decrease BMI less than 30 by transplant exhibited an increased risk of postoperative mortality (odds ratio, 2.62; 95% confidence interval, 1.01-6.48) compared with patients in group C. Pre-LTx BMI evolution had no impact on postoperative morbidity and mortality in underweight patients.

CONCLUSIONS

Our results suggest that obese candidates with an unfavorable pretransplant BMI evolution are at greater risk of worse post-LTx outcomes.

Weight loss prior to lung transplantation is associated with improved survival

BACKGROUND

Obesity is associated with increased mortality after lung transplantation and is a relative contraindication to transplant. It is unknown whether weight reduction prior to transplantation ameliorates this risk. Our objective was to determine whether weight loss prior to lung transplantation improves survival.

METHODS

Our investigation was a two-center, retrospective cohort study of lung transplant recipients between January 1, 2000 and November 5, 2010. Change in weight, demographics, transplant details, lung allocation score, length of intensive care and mechanical ventilator days and graft and patient survival were abstracted. Wilcoxon's signed-rank test and the Cox proportional hazard model were used for analysis where appropriate.

RESULTS

Three hundred fifty-five patients (55% male, median age 59 years) satisfied inclusion and exclusion criteria. After adjusting for standard demographic and clinical measures, a 1-unit reduction in BMI pre-transplant was associated with a reduced risk of death with a hazard ratio 0.89 (95% confidence interval 0.82 to 0.96; p = 0.004). This survival benefit persisted in the group with baseline BMI ≥ 25 kg/m(2) (overweight and obese) and hazard ratio 0.85 (95% CI 0.77 to 0.95; p = 0.003), but not in those with a BMI ≤ 24.9 kg/m(2). The 1-unit reduction in BMI was also associated with a 6.1% decrease in median mechanical ventilator days (p = 0.02) and a trend toward decreased intensive care unit length of stay (p = 0.06).

CONCLUSIONS

A reduction in BMI prior to lung transplantation was associated with a reduction in the risk of death and mechanical ventilator days. A greater reduction in BMI was associated with a greater survival benefit.

Lung transplantation in patients with cystic fibrosis: special focus to infection and comorbidities

Despite advances in medical care, patients with cystic fibrosis still face limited life expectancy. The most common cause of death remains respiratory failure. End-stage cystic fibrosis can be treated with lung transplantation and is the third most common reason for which the procedure is performed. Outcomes for cystic fibrosis are better than most other lung diseases, but remain limited (5-year survival 60%). For patients with advanced disease lung transplantation appears to improve survival. Outcomes for patients with Burkholderia cepacia remain poor, although they are better for patients with certain genomovars. Controversy exists about Mycobacterium abscessus infection and appropriateness for transplant. More information is also becoming available for comorbidities, including diabetes and pulmonary hypertension among others. Extra-corporeal membrane oxygenation is used more frequently for end-stage disease as a bridge to lung transplantation and will likely be used more in the future.

Changes in body composition after lung transplantation in children

BACKGROUND

The evaluation of nutritional status, including body composition measurements, in pediatric patients before and after lung transplant (LTx) can aid in adapting nutrition support and physical rehabilitation programs to meet individual patient needs. The purpose of this retrospective study was to determine the changes in weight, lean body mass (LBM), and body fat (BF) before and after LTx and their association with lung function in pediatric patients.

METHODS

Included were 41 LTx patients, aged 3 months to 20.7 years, who had at least 2 body composition measurements determined by dual-energy X-ray absorptiometry (GE Lunar Prodigy, Waukesha, WI) in the first 2 years after LTx were measured pre-LTX and at 12 or 24 months post-LTX, for weight, LBM, and BF.

RESULTS

Pre-LTx, 29% of patients had moderate and 12% had severe chronic malnutrition (growth stunting). This compares with 21% of patients being moderately LBM-depleted and 23% being BF-depleted. The weight change at 12 and 24 months was +9.3% (interquartile range, 5.6%-23%) and +4.7% (0.9%-11.6%), respectively; whereas the LBM change at 12 and 24 months was +15.2% (6.8%-17.1%) and +4.2% (-0.6% to 7.7%), respectively. LBM percentiles correlated with pulmonary function tests ( % predicted forced vital capacity [ρ = 0.36, p = 0.001] and forced expiratory volume in 1 second [ρ = 0.265, p = 0.015).

CONCLUSIONS

Maximum weight and LBM gain occur at 12 months after LTx, with smaller gains noted at 24 months. Clinicians must look beyond height and weight and evaluate LBM and fat mass in pediatric patients after LTx.