Trends, Determinants, and Impact on Survival of Post-Lung Transplant Weight Changes: A Single-center Longitudinal Retrospective Study

Can we HALT obesity following lung transplant? A Dietitian- and Physiotherapy-directed pilot intervention

INTRODUCTION

Unintentional weight gain, overweight and obesity following solid organ transplantation (SOT) are well-established and linked to morbidity and mortality risk factors. No interventional studies aimed at prevention have been undertaken among lung transplant (LTx) recipients. The combination of group education and telephone coaching is effective in the general population but is untested among SOT cohorts.

METHODS

A non-randomised, interventional pilot study was conducted among new LTx recipients. The control group received standard care. In addition to standard care, the intervention involved four group education and four individual, telephone coaching sessions over 12-months. Data collection occurred at 2 weeks, 3- and 12 months post-LTx. Measurements included weight, BMI, fat mass (FM), fat mass index (FMI), fat-free mass (FFM), fat-free mass index (FFMI), waist circumference (WC), visceral adipose tissue (VAT), nutrition knowledge, diet, physical activity, lipid profile, HbA_1C , FEV₁ , six-minute walk distance and patient satisfaction.

RESULTS

Fifteen LTx recipients were recruited into each group. One control participant died 120 days post-LTx, unrelated to the study. There were trends towards lower increases in weight (6.7±7.2kg vs 9.8±11.3kg), BMI (9.6% of baseline vs 13%), FM (19.7% vs 40%), FMI, VAT (7.1% vs 30.8%) and WC (5.5% vs 9.5%), and greater increases in FFM and FFMI (all p>0.05), among the intervention group by 12 months. The intervention was well-accepted by participants.

CONCLUSION

This feasible intervention demonstrated non-significant, but clinically meaningful, favourable weight and body composition trends among LTx recipients over 12 months compared to standard care. Australian New Zealand Clinical Trials Registry (ACTRN12619001606178) This article is protected by copyright. All rights reserved.

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.