Intensive nutritional counselling obviates a weight gain in kidney transplant recipients with long-term graft survival in Estonia

Introduction

The management of nutritional status is an important component of the complex care of chronic kidney disease (CKD) patients. Nutritional status, especially a state of malnutrition or obesity in end stage CKD patients, is linked to increased morbidity and mortality. On the other hand, after successful kidney transplantation (KTx), renal function recovers and appetite in kidney recipients tends to increase rapidly, often leading to weight gain (WG), which, together with increased body mass index (BMI), has a negative impact on health, cardiovascular and surgical outcomes. Body WG is an important risk factor for the development of chronic transplant nephropathy. Historically, studies by many researchers have found overall trends in WG over the first couple of years after KTx, with most WG occurring in the first year after surgery¹. Therefore, appropriate early nutritional management plays an important role in the prevention or reversal of this trend.

Despite the abundance of cross-sectional data on the relationship between body composition and nutrient intake, there are few long-term studies of body composition changes in KTx patients or studies that combine dietary intake and body composition². However, because of a lack of evidence for effective interventions that prevent weight gain after kidney transplantation, Australian researchers have recently designed a randomized controlled study³ called the INTENT trial (INTEnsive Nutrition interventions on weight gain after kidney Transplantation). The INTENT trial is a single-blind, randomized controlled trial for assessing the effects of intensive nutrition interventions, including exercise advice, on WG and metabolic parameters in the first year after transplantation⁴. Thus, the results may soon provide important data on the effects of intensive nutrition interventions on WG after transplantation and the associated metabolic consequences.

In addition to nutritional counselling after KTx at our transplant centre, which also routinely provides usual dietary guidance for patients, we also initiated more than 10 years ago a program that incorporates nutritional counselling and guidance for the whole CKD patient population. Besides implementing international⁴ and local^5,6 guidelines into clinical practice, we also conducted a longitudinal prospective study in KTx recipients with long-term graft survival at Tartu University Hospital and looked at the impact of longitudinally intensive nutritional counselling on body composition. We hypothesised that patients who received intensive counselling may have better weight control compared with patients who did not receive such counselling. The purpose of the study was to assess the impact of intensive nutritional counselling on KTx patients in the prevention of post-transplant WG compared with standard dietary guidance in KTx patients. The secondary aim was to determine changes in macronutrient intake and body composition in patients after KTx. We further aimed to assess the long-term impact of intensive nutritional counselling 10 years after KTx on WG by comparing groups of intensively counselled and standard care patients.

Methods

Adult consecutive non-diabetic patients with stable kidney function who agreed to participate and gave written informed consent, were recruited for the first measurement (FM) at 18 months and for a follow-up at (FU) 36 months after kidney transplantation, performed in our centre between 2003 and 2006.

In total, 75 patients were studied; of these 28 KTx patients (12 males, mean age 42.8 ± 16.1 years and 16 females, mean age 47.0 ± 14.9 years) received intensive nutritional counselling. The remaining 47 KTx patients, who stayed in standard dietary guidance maintenance, formed the control group and this group consisted of 27 males (with a mean age of 45.6 ± 9.4 years and 20 females (with a mean age of 48.7 ± 12.8 years). Anthropometrical measurements (body weight, kg; body height, cm; body mass index, kg/m²) were assessed at FM, FU and then, finally, 10 years after the KTx in both groups of patients. WG was estimated taking into account a patients weight measurements at FM and comparing them with measurements after 10 years. Also, laboratory measurements and macronutrient intake were performed on counselled KTx patients twice: at FM and at FU.

All patients at our institution are provided with appropriate usual nutritional guidance before discharge after kidney transplantation. In our study, additional intensive nutritional counselling and dietary guidance at FM (18 months after the KTx) were carried out by a dietician who took into account individual patient’s anthropometrical, laboratory as well as nutritional investigations including the food frequency questionnaire (see Supplementary material 1) and the analysis of 3-day dietary records⁷ Individual nutritional counselling and dietary guidance were performed repeatedly. Nutritional counselling was performed by a dietician who took into consideration the patient`s age, gender, the stage of chronic kidney damage, proteinuria, build of the body, the 24-hour need for food energy and nutrients, and the patient`s eating habits. The consumption of energy and main nutrients content in the 3-day menus of kidney transplant patients was calculated and analysed with the Finnish food composition database program Micro-Nutrica Nutritional Analysis (https://fineli.fi/). All the data were compared with the Estonian Nutrition Recommendations⁸.

Ethics approval: The study was approved by the Ethics Committee on Human Research of the University of Tartu, Estonia (protocol no 141/30; 2005).

Results

Our previous results of detailed anthropological measurements at 18 and 36 months after KTx showed that females were more accurate to follow dietitians' advice compared to male patients⁹. We also showed previously that the mean body weight increased significantly among studied male KTx patients and in control KTx patients, both male and females, after the follow-up, but in female KTx patients the BW increase was non-significant⁹.

Now, in our current study 10 years after the KTx we further aimed to clarify the longitudinal effect of intensive nutritional counselling and guidance on WG. We noticed WG in all KTx patients, both in males and females, as follows: in the standard care group, the males' mean WG was 6.4 kg, the females' 7.0 kg and among intensively counselled males 4.6 kg and females 1.1 kg. But in Table 1, we demonstrate statistically non-significant weight change among counselled living KTx patients with long-term graft survival both in males (N=9, p = 0.0680) and females (N=11, p = 0.3166) which was registered 10 years after the KTx compared with the FM mean weight. Among standard care control KTx patients, weight change was statistically significant in both males and females (males: N=21, p = 0.0016; females: N=15, p = 0.0040) 10 years after the KTx.

We also observed and assessed macronutrient intake, which was determined at FM and at FU (Table 2). The food frequency questionnaire revealed that patients consumed various types of food (milk and dairy products; meat and fish products; cereal and flour products; vegetables; fruits; sweets) at different frequencies, but there was a tendency towards excessive consumption of food rich in proteins and carbohydrates in both males and females in FM. The following changes in nutrient intake were noticed: at FU, mean daily energy and protein intakes were significantly higher than FM in female patients, and in males, mean daily energy, protein, fat and carbohydrate intakes had a tendency to decrease after FU when compared with FM data. However, mean daily intakes of energy, fat and protein estimated at FM and at FU were adequate in both males and females when compared with the Estonian Dietary Reference Intakes⁸ (Table 2). Thus, there was a positive tendency in the change of the content of different macronutrients among all counselled subjects, although the directions in which macronutrient intake changed were not similar in males and females.

Discussion

The impact of obesity and overweight on clinical outcomes after serious disease, have long been the object of research, with contradictory results. In our study, WG was not significant 10 years after KTx in patients who received additional intensive nutritional counselling compared with standard care control KTx patients group.

We conclude that nutritional counselling and guidance is important and should be offered early and regularly after kidney transplantation to maintain body weight and appropriate nutritional state longitudinally. Post-transplant outcomes will be optimized by a team approach for the comprehensive management of the kidney transplantation recipient combined with vigilant surveillance to detect WG in a timely fashion. However, long-term WG data clearly showed that in our KTx patient population, the patients who received intensive individual dietary counselling had much more educated behaviour in the long-term, thereby preventing WG which is a really well-known risk factor for long-term graft failure as well as for cardiovascular complications and mortality. We are awaiting the final results of the Australian researchers³ with great interest.

Data availability

F1000Research: Dataset 1. Raw data supporting the patients’ long-term body weight gain findings in different study groups, 10.5256/f1000research.10035.d141569¹⁰