Body Mass Index in the First Year After Kidney Transplantation

Effect of Pre-Transplant Recipient Underweight on the Postoperative Outcome and Graft Survival in Primary Kidney Transplantation

BACKGROUND

The objective of this study was to evaluate the influence of recipient underweight on the short- and long-term outcomes of patients undergoing primary kidney transplantation (KT).

PATIENTS AND METHODS

Three hundred thirty-three patients receiving primary KT in our department between 1993 and 2017 were included in the study. Patients were divided according to their body mass index (BMI) into underweight (BMI <18.5 kg/m2; N = 29) and normal weight (BMI 18.5-24.9 kg/m2; N = 304) groups. Clinicopathological characteristics, postoperative outcomes, and graft and patient survival were analyzed retrospectively.

RESULTS

The postoperative rate of surgical complications and renal function were comparable between the groups. One year and 3 years after KT, 70% and 92.9%, respectively, of the pre-transplant underweight patients reached a normal BMI (≥18.5 kg/m2). The mean death-censored graft survival was significantly lower in pre-transplant underweight patients than in pre-transplant normal-weight patients (11.5 ± 1.6 years vs 16.3 ± 0.6 years, respectively; P = .045). Especially KT recipients with a moderate or severe pre-transplant underweight (BMI <17 kg/m2; N = 8) showed an increased rate of graft loss (5- and 10-year graft survival: 21.4% each). No statistical difference could be observed between the 2 groups regarding causes of graft loss. In multivariate analysis, recipient underweight (P = .024) remained an independent prognostic factor for graft survival.

CONCLUSION

Being underweight did not affect the early postoperative outcome after primary KT. However, underweight, and especially moderate and severe thinness, is associated with reduced long-term kidney graft survival, and therefore this group of patients should be monitored with special attention.

The Impact and Effectiveness of Weight Loss on Kidney Transplant Outcomes: A Narrative Review

Obesity is a worldwide epidemic that leads to several non-communicable illnesses, including chronic kidney disease (CKD). Diet and lifestyle modifications have shown a limited impact in the treatment of obesity. Because the group of end-stage renal disease (ESRD) patients examined in this study had limited access to kidney transplantation (KT), patients with obesity were thought to be at an increased risk of intraoperative and postoperative KT complications. Although bariatric surgery (BS) is now recognized as the gold standard treatment for morbid obesity, its role in ESRD or kidney transplant patients remains unknown. It is critical to know the correlation between weight loss and complications before and after KT, the impact of the overall graft, and patients' survival. Hence, this narrative review aims to present updated reports addressing when to perform surgery (before or after a KT), which surgical procedure to perform, and again, if strategies to avoid weight regain must be specific for these patients. It also analyzes the metabolic alterations produced by BS and studies its cost-effectiveness pre- and post-transplantation. Due to the better outcomes found in KT recipients, the authors consider it more convenient to perform BS before KT. However, more multicenter trials are required to provide a solid foundation for these recommendations in ERSD patients with obesity.

Weight gain after renal transplant: Incidence, risk factors, and outcomes

Background

Renal transplantation is the definitive treatment for patients with end-stage renal disease (ESRD). It is associated with better quality of life and patient survival. Nevertheless, these benefits come with rising concerns about weight gain and metabolic abnormalities, which adversely impact transplant outcomes.

Objective

The objective of this study is to estimate the incidence of weight gain in the first year post-renal transplant in addition to the assessment of potential risk factors and the resulting outcome of the graft.

Methods

We conducted a single-center retrospective cohort study of all 295 patients who underwent kidney transplantation at King Abdulaziz Medical City (KAMC) between January 2016 and December 2019. Clinical and laboratory variables were collected from electronic records. Continuous variables were reported as mean ± standard deviation. Comparison between groups was assessed by unpaired t-test or Mann-Whitney U test while follow-up data were compared using paired t-test and repeated measures ANOVA. Association between the potential risk factors and the weight gain was assessed by means of binary logistic regression analysis.

Results

Significant weight gain was observed in 161 (54.6%) patients. Females were 119 (40.30%) of the cohort. The mean age was 45.3±15.1 years. The prevalence of diabetes was 234 (79.6%), while hypertensives constituted 77 (26.3%). The comparison between patients who gained weight significantly and patients with stable weight showed a numerical higher prevalence of female gender in patients who had more weight gain (44.1% vs. 35.8%), higher diabetes, higher rate of a living donor, and statistically significant lower dialysis duration before transplant. Other clinical and laboratory variables were comparable between the two groups.

Conclusion

Our study showed a high incidence of clinically significant weight gain among patients post-renal transplantation. Patients with lower dialysis duration, a living kidney donor and those who are obese at baseline were at higher risk of gaining weight. Patients who underwent kidney transplantation should be monitored closely for weight gain and further studies are needed to determine the risk factors and appropriate interventions.

Risk factors associated with weight gain after kidney transplantation: A cohort study

BACKGROUND

Renal transplantation is the best modality of renal replacement therapy for patients with end-stage renal disease. However, it is associated with weight gain and metabolic abnormalities, which adversely impact transplant outcomes.

OBJECTIVE

The objective of this study was to identify the risk factors of one-year weight gain after renal transplantation.

METHODS

A retrospective cohort study was conducted with 374 patients that underwent kidney transplantation between January 2006 and July 2013. Clinical and laboratory variables were collected from electronic records, and the outcome of interest was weight gain during the first year after renal transplantation. The data were reported as mean ± standard deviation, median (interquartile range) or number of subjects (%). The association between variables were assessed via chi-square test and ANOVA. For analysis of risk factors related to the outcomes of interest, multivariable logistic regression models were used.

RESULTS

There were 181 (48.4%) female patients, 334 (89.3%) with white ethnicity and the mean age was 44.4 ± 12.8 years. The mean BMI pre-transplant was 24.7 ± 4.1 kg/m2, and 35 (9.9%) patients were classified as obese; 119 (33.6%) as overweight; 187 (52.8%) as normal weight; and 13 (3.7%) as malnourished. After one year of follow-up, the mean BMI was 26.2 ± 5.0 kg/m2, and 61 (17.3%) patients were classified as obese; 133 (37.8%) as overweight; 148 (42.0%) as normal weight; and 10 (2.8%) as malnourished. Weight gain was observed in 72.7% patients, and the average increase was 7.12 ± 5.9 kg. The female gender, lower pre-transplant body weight, lower number of hospitalizations, and a kidney received from a living donor were associated with weight gain by more than 5% in the first year post-transplant.

CONCLUSION

Female gender and lower pre-transplant body weight were independently associated with weight gain by more than 5% in the first year after kidney transplantation; lower rates of hospitalization and donation from living donors were also risk factors for this outcome.

Malnutrition according to GLIM criteria in stable renal transplant recipients: Reduced muscle mass as predominant phenotypic criterion

BACKGROUND & AIMS

Malnutrition has a negative impact on quality of life and survival in renal transplant recipients (RTR). Therefore, malnutrition detection is important in RTR, but this may be hampered by concomitant presence of weight gain and overweight. Recently, the Global Leadership Initiative on Malnutrition (GLIM) developed a set of diagnostic criteria for malnutrition. We aimed to assess the prevalence of malnutrition according to the GLIM criteria and the distribution of phenotypic criteria in RTR. Additionally, we examined the potential value of 24-h urinary creatinine excretion rate (CER) as alternative measure for the criterion reduced muscle mass.

METHODS

We used data from stable outpatient RTR included in the TransplantLines Cohort and Biobank Study (NCT02811835). Presence of weight loss and reduced intake or assimilation were derived from Patient-Generated Subjective Global Assessment (PG-SGA) item scores. Reduced muscle mass was assessed by multi-frequency bio-electrical impedance analysis (MF-BIA) and defined as an appendicular skeletal muscle mass index (ASMI) < 7 kg/m² for men and <5.5 kg/m² for women, and in additional analysis defined as creatinine-height index (CHI, based on 24 h urine CER) < 80%. Inflammation was present if C-reactive protein (CRP) was >5 mg/L. Malnutrition was defined as presence of at least one phenotypic (weight loss and/or low BMI and/or reduced muscle mass) and one etiologic criterion (reduced intake/assimilation and/or disease burden/inflammation).

RESULTS

We included 599 RTR (55 ± 13 years old, 62% male, BMI 27.2 ± 4.7 kg/m²) at a median of 3.1 years after transplantation. According to GLIM criteria, 14% was malnourished, of which 91% met the phenotypic criterion for reduced muscle mass. Similar results were found by using CHI as measure for muscle mass (13% malnutrition of which 79% with reduced muscle mass).

CONCLUSIONS

Malnutrition is present in one in 7 stable RTR, with reduced muscle mass as the predominant phenotypic criterion. Assessment of nutritional status, most importantly muscle status, is warranted in routine care, to prevent malnutrition in RTR from remaining undetected and untreated. The diagnostic value of 24-h urinary CER in this regard requires further investigation.

Weight Gain, Energy Intake, Energy Expenditure, and Immunosuppressive Therapy in Kidney Transplant Recipients

BACKGROUND

Weight gain after kidney transplantation is a common health problem. The factors in weight gain after kidney transplant include many factors such as age, ethnicity, gender, change in lifestyle (eg, kilocalorie intake and physical activity level), and immunosuppressive therapy.

RESEARCH QUESTIONS

This study aimed to evaluate the relationship between weight gain and energy intake in dietary, energy expenditure in physical activity, and immunosuppressive therapy in kidney transplant recipients.

DESIGN

This prospective, observational study included 51 participants who underwent kidney transplant, during 6 months from the start of the study. Anthropometric measurements were performed at first week, third- and sixth-month follow-ups of transplant recipients. Participants also completed 3-day "Dietary Record Form" and the "Physical Activity Record Form" at each follow-up. Simple frequency, analysis of variance analysis, and correlation analysis were used for data analysis.

RESULTS

Weight gain in sixth month follow-up compared to baseline value was positively related to energy intake in first week (r = 0.59), third month (r = 0.75), and sixth month (r = 0.67) follow-ups, and energy expenditure in first week (r = 0.35) and sixth month (r = 0.34) follow-ups. However, weight gain was negatively related to mycophenolate mofetil dose (mg/d) in sixth month (r = -0.31) follow-up (P < .05).

DISCUSSION

The results of this study provide an opportunity to reflect and discuss on modifiable risk factors such as energy intake and energy expenditure that affect weight gain posttransplantation in participants. It also examines the relationship between immunosuppressive therapy. Additionally, these results can be effective in designing interventions and managing risk factors to achieve weight management goals.

Nutrition Trends in Patients Over the Long Term After Kidney Transplantation

OBJECTIVES

Nutritional behaviors may exert important influence on morbidity and graft function in patients after kidney transplantation (KT). Nutritional status is closely related to potential risk factors of developing posttransplant complications, including diabetes mellitus, weight gain, and negative effects on immunosuppressive therapy. The aim of this study was to assess the dietary intake in patients after KT.

DESIGN AND METHODS

Nutritional intake of 154 (61 women and 93 men) patients was assessed based on a questionnaire regarding food intake (proteins, fats, carbohydrates, cholesterol, sugar, phosphorus, calorific value) within 3 working days preceding the routine outpatient posttransplant visit. Patient medical history, concomitant medications, and estimated glomerular filtration rate (eGFR) was obtained from medical charts.

RESULTS

The mean age (years) ± SD of patients was 51.9 ± 14.1. The patients were evaluated 94 ± 67 months after KT, with a median eGFR of 53 (range, 41.2-64.1) mL/min/1.73 m². Sixty-two percent of patients had increased body mass index values. The mean total energy intake was 2159.4 ± 551.9 kcal/day. The patients reported elevated salt (8.5 ± 2.4 g per day) and fat intake (99.4 ± 3.2 g per day) including 57% saturated fatty acids. The patients consumed products containing high amounts of sugars (108.2 ± 107.0 g per day), carbohydrates (238.3 ± 64.3 g per day), and cholesterol (303.6 ± 11.1 mg per day). The diet among kidney recipients consisted predominantly of fats, meat, cured meat, and sweets.

CONCLUSIONS

The nutritional behaviors of patients after KT are in most cases poor. Improvement of eating habits in these patients seems to be a simple method to preserve kidney function over the long term.

Approach and Management of Hypertension After Kidney Transplantation

Hypertension is one of the most common cardiovascular co-morbidities after successful kidney transplantation. It commonly occurs in patients with other metabolic diseases, such as diabetes mellitus, hyperlipidemia, and obesity. The pathogenesis of post-transplant hypertension is complex and is a result of the interplay between immunological and non-immunological factors. Post-transplant hypertension can be divided into immediate, early, and late post-transplant periods. This classification can help clinicians determine the etiology and provide the appropriate management for these complex patients. Volume overload from intravenous fluid administration is common during the immediate post-transplant period and commonly contributes to hypertension seen early after transplantation. Immunosuppressive medications and donor kidneys are associated with post-transplant hypertension occurring at any time point after transplantation. Transplant renal artery stenosis (TRAS) and obstructive sleep apnea (OSA) are recognized but common and treatable causes of resistant hypertension post-transplantation. During late post-transplant period, chronic renal allograft dysfunction becomes an additional cause of hypertension. As these patients develop more substantial chronic kidney disease affecting their allografts, fibroblast growth factor 23 (FGF23) increases and is associated with increased cardiovascular and all-cause mortality in kidney transplant recipients. The exact relationship between increased FGF23 and post-transplant hypertension remains poorly understood. Blood pressure (BP) targets and management involve both non-pharmacologic and pharmacologic treatment and should be individualized. Until strong evidence in the kidney transplant population exists, a BP of <130/80 mmHg is a reasonable target. Similar to complete renal denervation in non-transplant patients, bilateral native nephrectomy is another treatment option for resistant post-transplant hypertension. Native renal denervation offers promising outcomes for controlling resistant hypertension with no significant procedure-related complications. This review addresses the epidemiology, pathogenesis, and specific etiologies of post-transplant hypertension including TRAS, calcineurin inhibitor effects, OSA, and failed native kidney. The cardiovascular and survival outcomes related to post-transplant hypertension and the utility of 24-h blood pressure monitoring will be briefly discussed. Antihypertensive medications and their mechanism of actions relevant to kidney transplantation will be highlighted. A summary of guidelines from different professional societies for BP targets and antihypertensive medications as well as non-pharmacological interventions, including bilateral native nephrectomy and native renal denervation, will be reviewed.

Nutritional management in renal transplant recipients: A transplant team opportunity to improve graft survival

AIMS

The nutritional management of renal transplant recipients (RTR) represents a complex problem either because the recovery of renal function is not complete and for the appearance of "unavoidable" metabolic side effects of immunosuppressive drugs. Nevertheless, it remains a neglected problem, whereas an appropriate dietary intervention could favorably affect graft survival.

DATA SYNTHESIS

Renal transplantation is associated with steroids and calcineurin inhibitors administration, liberalization of diet after dialysis restrictions, and patients' better quality of life. These factors predispose, from the first months after surgery, to body weight gain, enhanced post transplant diabetes, hyperlipidemia, metabolic syndrome, with negative consequences on graft outcome. Unfortunately, specific guidelines about this topic and nutritional counseling are scarce; moreover, beyond the low adherence of patients to any dietary plan, there is a dangerous underestimation of the problem by physicians, sometimes with inadequate interventions. A prompt and specific nutritional management of RTR can help prevent or minimize these metabolic alterations, mostly when associated with careful and repeated counseling.

CONCLUSIONS

A correct nutritional management, possibly tailored to enhance patients' motivation and adherence, represents the best preventive maneuver to increase patients' life and probably improve graft survival, at no cost and with no side effects.

Are Females More Prone Than Males to Become Obese After Kidney Transplantation?

Background

Being overweight for kidney transplant recipients can cause serious side effects. Weight gain affects two-thirds of kidney transplant recipients and has been attributed to a more liberal diet after transplantation, recovery of appetite due to lack of uremic toxicity, corticosteroid use, and inadequate lifestyle changes. The aim of this study was to assess gender-dependent profile of body mass index (BMI) changes after kidney transplantation (KTx).

Material/Methods

Sixty-two kidney transplant recipients (38 males and 24 females), aged 46.0±12.8 years at KTx, were observed according to weight gain after KTx. BMI was calculated before transplantation (pre-KTx) and at 6, 12, and 24 months post-KTx.

Results

During the 24-month observation period, we found an increase in the incidence of kidney transplant recipients being overweight or obese (pre-KTx 43.5% increase and 24-month post-Ktx 61.3% increase, P=0.036). We analyzed a number of factors that could potentially influence a 24-month BMI gain including age at KTx, gender, pre-KTx BMI, time on dialysis, pre-KTx glucose metabolism disorder, and post-KTx diabetes mellitus. For female recipients, there was a significant step-wise post-KTx increase in BMI during the 24-month observation period. The overall pre-KTx to 24-month net increase for female BMI was 2 times greater than that observed for male recipients (1.90±2.20 kg/m² versus 0.89±1.85 kg/m², P<0.001).

Conclusions

Weight gain after KTx was observed in both sexes, but the net BMI increase was more than 2 times greater in females than in males at 24-months post-KTx. This indicated the need for diet education and strict weight control in kidney transplant recipients, especially in female patients.

The impact of plasma brain-derived neurotrophic factor concentration and weight gain after kidney transplantation

Obesity and its related complications continue to be significant challenges for kidney transplant recipients. In previous studies, researchers have reported that brain-derived neurotrophic factor (BDNF) is closely associated with metabolic imbalance and obesity, but the role of BDNF in weight gain after kidney transplant has not been elucidated. The purpose of this pilot study was to explore the relationship between plasma BDNF levels and weight change. We examined associations between plasma BDNF levels measured at transplantation and 12 months later and measures of weight change during these 12 months in a sample of 55 kidney recipients (mean age of 48 years, 60% male, 56% African American). Of the 55 recipients, 49 had BDNF levels measured at baseline, 33 had BDNF levels measured at 12 months, and 27 had BDNF levels measured at both time points. We found that plasma BDNF levels at baseline (n = 49), but not at 12 months (n = 33), were significantly and positively correlated with the body mass index change (p = 0.037) and percentage weight change (p = 0.036). In addition, average plasma BDNF value at 12 months (307 ± 254 pg/ml) was significantly lower than at baseline (452 ± 345 pg/ml) in the 27 recipients with BDNF levels measured at both time points. Findings from this pilot work suggest that BDNF might serve as a regulator of weight change for kidney transplant related obesity.

Different Dietary Patterns and New-Onset Diabetes Mellitus After Kidney Transplantation: A Cross-Sectional Study

OBJECTIVE

To verify the association of dietary patterns and dietary components with new-onset diabetes mellitus after transplantation (NODAT).

DESIGN

Cross-sectional study.

SUBJECTS

Adult kidney transplant recipients, without history of diabetes before transplantation, who received a kidney transplant and were followed up for at least 1 year. One hundred and sixteen subjects recruited between January 2013 and August 2014. Diagnosis of NODAT was established according to the American Diabetes Association criteria for type 2 diabetes.

METHODS

Demographic, clinical, and anthropometric data were collected. Dietary intake was assessed by food frequency questionnaire, administered by a registered dietitian. Dietary patterns were identified by cluster analysis. Chi-square test was used to verify the association between dietary patterns and NODAT. Total energy, fiber, and cholesterol intake were calculated. Consumption of macronutrients, carbohydrates, proteins, and fats (total fats and saturated, monounsaturated, polyunsaturated and trans fatty acids), were expressed in percentage of total energy intake.

RESULTS

Twenty-eight patients developed NODAT in the follow-up period. They presented higher body mass index and body fat percentage, as well as higher levels of triglycerides and urinary protein/creatinine ratio than the non-NODAT group. Two dietary patterns, I and II, were identified. Pattern II was characterized by higher intake of total, saturated, monounsaturated, and trans fats than pattern I. No association between the dietary patterns and NODAT was identified (P = .905), and there was no difference in the distribution of macronutrients, dietary fiber, and dietary cholesterol between the groups with and without NODAT.

CONCLUSION

Posttransplant dietary patterns were not different between patients with and without NODAT. Further larger and prospective studies are needed to evaluate a possible relationship between dietary components and NODAT incidence in kidney transplant recipients.

Influence of the recipient body mass index on the outcomes after kidney transplantation

PURPOSE

The relationship between the body mass index (BMI) of kidney transplant recipients and outcomes after kidney transplantation (KT) is not fully understood and remains controversial. We studied the influence of BMI on clinically relevant outcomes in kidney transplant recipients.

METHODS

In this retrospective single-centre study, all patients who underwent kidney transplantation at our institution between January 2007 and December 2012 were included. Demographic data and BMI were correlated with the clinical course of the disease, rejection rates, delayed graft function rates, and graft and patient survival.

RESULTS

During the study period, 384 single KTs (130 women and 254 men) were performed. Seventeen percent of the transplants were transplanted within the Eurotransplant Senior Programme (ESP). Most of the transplants were performed using organs that were obtained from donors after brain death (DBD), and living donor kidney transplants were performed in 22.4% of all transplants. The median BMI of the recipients was 25.9 kg/m². Additionally, 13.5% of the recipients had a BMI of 30-34.9 kg/m² and 3.9% had a BMI >35 kg/m². A BMI >30 kg/m² was significantly associated with primary non-function of the kidney (p = 0.047), delayed graft function (p = 0.008), and a higher rate of loss of graft function (p = 0.015). The glomerular filtration rate 12 months after KT was significantly lower in recipients with a BMI >30 kg/m². Multivariate analysis revealed that recipient BMI, among other factors, was an independent risk factor for delayed graft function and graft survival. Patients with a BMI >30 kg/m² had an almost four times higher risk for surgical site infection than did recipients with a lower BMI.

CONCLUSIONS

Increased BMI at kidney transplantation is a predictor of adverse outcomes, including delayed graft function. These findings demonstrate the importance of the careful selection of patients and pre-transplant weight reduction, although the role of weight reduction for improving graft function is not clear.

Increase in Body Mass Index After Renal Transplantation

The aim of this study was to determine the changes in body mass index (BMI) of patients after renal transplantation regarding causes like steroid use, lower necessity for dietary restrictions, and changes in eating habits. Ninety-seven patients were enrolled in this retrospective study; they had undergone cadaver or living donor renal transplantation between 2011 and 2013. Demographic features of patients, height, weight, and BMI were evaluated before and 6 and 12 months after surgery. The patients were grouped as malnutritioned, normal, overweight, and obese. Statistical analyses were performed using the SPSS 11.0 statistics program. Mean age of patients was 39.1 ± 10.7 years. Twenty-six (26.8%) were female and 71 (73.1%) were male. Mean BMI before surgery was 22.52 ± 3.97 kg/m(2). Six months post-transplantation the mean BMI was 24.40 ± 4.1 kg/m(2) and after 12 months it was 25.56 ± 4.14 kg/m(2) (P < .05). Also, 68% of patients showed improvement 12 months after surgery; they were in the preoperative malnutrition group. There is a significant increase in the BMI of patients in the first year who undergo renal transplantation, and the reason is multifactorial. BMI is relevant to diabetes, hypertension, and allograft nephropathy. BMI should be carefully considered in the follow-up of patients who have undergone renal transplantation, and early nutritional changes with dietary and exercise programs should be performed in overweight cases.