Impact of Pretransplant Body Mass Index on Early Kidney Graft Function

Background

An increase in the number of obese patients on transplantation waiting lists can be observed. There are conflicting results regarding the influence of body mass index (BMI) on graft function.

Methods

We performed a single-center, retrospective study of 859 adult patients who received a renal graft from deceased donors. BMI (kg/m²) was calculated from patients' height and weight at the time of transplantation. Kidney recipients were subgrouped into 4 groups, according to their BMI: Groups A (<18.5; n = 57), B (18.6–24.9; n = 565), C (25–29.9; n = 198) and D (>30; n = 39). Primary or delayed graft function (DGF), acute rejection (AR) episodes, and number of reoperations, graft function expressed by glomerular filtration rate (GFR) and serum creatinine concentration and number of graft loss as well as the recipient's death were analyzed. The follow-up period was 1 year.

Results

Obese patients' grafts do not develop any function more frequently in comparison with their nonobese counterparts (P < .0001; odds ratio [OR], 32.364; 95% CI, 2.174–941.422). Other aspects of the procedure were analyzed to confirm that thesis: Cold ischemia time and number of HLA mismatches affect the frequency of AR (OR, 1.0182 [P = .0029] and OR, 1.1496 [P = .0147], respectively); moreover, donor median creatinine serum concentration (P = .00004) and cold ischemia time (P = .00019) are related to delayed graft function. BMI did not influence the incidence of DGF (P = .08, OR; 1.167; 95% CI, 0.562–2.409), the number of AR episodes (P > .1; OR, 1.745; 95% CI, 0.846–3.575), number of reoperations, GFR (P = .22–.92), or creatinine concentration (P = .09). Number of graft losses (P = .12; OR, 1.8; 95% CI, 0.770–4.184) or patient deaths (P = .216; OR, 3.69; 95% CI, 0.153–36.444) were not influenced.

Conclusion

Greater recipient BMI at the time of transplantation has a significant influence on the incidence of primary graft failure.     

Effect of Changes in Body Mass Index on Cardiovascular Outcomes in Kidney Transplant Recipients

Background

A higher body mass index (BMI) before kidney transplantation (KT) is associated with increased mortality and allograft loss in kidney transplant recipients (KTRs). However, the effect of changes in BMI after KT on these outcomes remains uncertain. The aim of this study was to investigate the effect of baseline BMI and changes in BMI on clinical outcomes in KTRs.

Kidney and Recipient Weight Incompatibility Reduces Long-Term Graft Survival

Long-term function of kidney allografts depends on multiple variables, one of which may be the compatibility in size between the graft and the recipient. Here, we assessed the long-term consequences of the ratio of the weight of the kidney to the weight of the recipient (KwRw ratio) in a multicenter cohort of 1189 patients who received a transplant between 1995 and 2006. The graft filtration rate increased by a mean of 5.74 ml/min between the third and sixth posttransplantation months among patients with a low KwRw ratio (<2.3 g/kg; P < 0.0001). In this low KwRw ratio group, the graft filtration rate remained stable between 6 months and 7 years but then decreased at a mean rate of 3.17 ml/min per yr (P < 0.0001). In addition, low KwRw ratios conferred greater risk for proteinuria, more antihypertensive drugs, and segmental or global glomerulosclerosis. Moreover, a KwRw ratio <2.3 g/kg associated with a 55% increased risk for transplant failure by 2 years of follow-up. In conclusion, incompatibility between graft and recipient weight is an independent predictor of long-term graft survival, suggesting that avoiding kidney and recipient weight incompatibility may improve late clinical outcome after kidney transplantation.The effect of nephron reduction has long been described in animal models as well as in humans^1,2 and is thought to be a potential “nonimmunologic” risk factor for chronic graft dysfunction after kidney transplantation.^3,4 The paradigm generally considered to account for the deleterious effect of nephron reduction on graft function is that of “adaptive” hyperfiltration of the remaining glomeruli, ultimately leading to glomerulosclerosis.^5–7 In accordance with this hypothesis, individuals who have undergone nephrectomy have been shown to develop high BP and proteinuria decades after the nephrectomy,^8–11 as in the case of older recipients with a higher body mass index¹²; however, renal insufficiency only appears in the case of a 75% reduction in kidney mass and after at least 10 years of follow-up.⁹ Kidney transplantation has been proposed as an accelerated model of nephron reduction resulting from the accumulation of several unfavorable factors. For example, repeated injuries, from initial brain death of the donor¹³ to ischemia-reperfusion injury,¹⁴ negatively affect the transplant. Moreover, superimposed immunologic and nonimmunologic events further decrease the initial nephron mass of a transplant and serve only to exacerbate the consequences of hyperfiltration related to its single kidney status.Given that kidney weight (Kw) and glomerular volume (but not nephron number) correlate with body surface area (BSA),¹⁵ several studies have already analyzed the effect of donor and recipient BSA mismatches.^7,16–19 The effect of kidney graft size and recipient weight (Rw)^20,21 has also been studied; however, the direct impact of matching the Kw itself (which correlates with both glomerular volume and nephron number)¹⁵ to the Rw has been studied only in relatively small cohorts of <300 patients and only in living donors,^22,23 where the graft does not incur the same accumulating injuries as those from deceased donors.We previously reported on the results of a first study²⁴ focusing on the impact of graft weight on clinical outcome; however, within the relatively short survey period of the latter study (mean 32 months; range 8 days to 94 months), no impact on short-term graft survival was observed. Because renal failure has been described a decade after nephron reduction,^3,10,25 we reappraised our historical cohort to which an additional 47 patients were included (whole population n = 1189) at a mean of 6.2 years from transplantation (range 8 days to 13 years). We now report that the magnitude of the Kw and Rw incompatibility is significantly associated not only with sustained “adaptive” hyperfiltration and early proteinuria but also with an increased risk for hypertension requiring more medication, a higher incidence of segmental or global glomerulosclerosis, and a significantly poorer long-term transplant survival.     

Effects of Body Mass Index Changes In Pediatric Kidney Transplant Patients

BackgroundThe negative effects of pretransplant obesity and post-transplant body mass index (BMI) increase on graft survival have been reported in recent years. The aim of this study is to evaluate the effects of BMI changes on post-transplant graft function, lipid profile, and blood pressure.MethodsThe study included 133 pediatric patients transplanted between 1994 and 2019 in Ege University. BMI Z-scores (BMIZs) were calculated according to age and sex before and after transplantation using the World Health Organization criteria. Patients with BMIZs >+1 standard deviation (SD) were defined as overweight, and those with BMIZs >+2 SD were defined as obese: Group 1: Obese or overweight before transplantation; Group 2: Thin or normal weight before and 2 years after transplantation; and Group 3: Thin or normal weight before transplantation and obese or overweight 2 years after transplantation.ResultsAt the time of transplantation 8% of the patients were overweight, and 1% were obese. Overweight and obesity statistically significantly increased (31.6%) 2 years after renal transplantation (P = .001). Obese and overweight patients have lower high-density lipoprotein levels and were younger at the time of transplantation. Graft functions, lipid levels, and blood glucose levels of the groups were similar (P > .05). The only significant difference between the groups was that Group 1 patients were younger than Group 2.ConclusionsObesity develops at a significant rate in pediatric patients after renal transplantation. In this study, we could not demonstrate negative effects of obesity and being overweight in terms of post-transplant graft function, lipid profile, blood glucose, and blood pressure.     

Factor Analysis for Body Mass Index Changes in Kidney Transplant Recipients

BackgroundThe purpose of this study was to identify factors influencing changes in the body mass index (BMI) of kidney transplant (KT) patients and provide data for the management of the BMI of patients who have undergone KT.MethodThe participants were 106 patients who underwent KT at a single center from August 2014 to June 2017. BMIs were compared and analyzed for 6 months and 24 months after KT, and the survey details were collected through medical records. Analysis was performed between 2 groups, one with increased BMI and the other without. Multivariate logistic regression analysis was performed to identify the factors related to an increase in BMI.ResultsBMI increased from 22.60 ± 2.72 kg/m² at 6 months to 23.18 ± 3.06 kg/m² 2 years after KT. The group with increased BMI (n = 39) had more patients with higher low-density cholesterol levels at the time of KT (low-density cholesterol ≥100 mg/dL; 34 [54.0%] vs 10 [26.3]; P = .008) and without statin drug use than the other group (n = 67) (statin drug use, 48 [70.6%] vs 34 [87.2%], P = .044). Multiple logistic regression analysis showed that age >50 years (odds ratio [OR] = 2.942; 95% confidence interval [CI], 1.075-8.055; P = .036), low-density lipoprotein >100 mg/dL at KT (OR = 6.618; 95% CI, 2.225-19.682; P = 0.001), and no statin drugs (OR = 5.094; 95% CI, 1.449-17.911, P = .011) were the risk factors for an increased BMI after KT.ConclusionsAfter KT, to prevent an increase in the BMI, clinicians should strongly recommend the use of drugs to treat hyperlipidemia, especially in elderly patients with high low-density lipoprotein levels before KT.     

Body Mass Index,Waist Circumference and Mortality in Kidney Transplant Recipients

Higher body mass index (BMI) appears paradoxically associated with better outcomes in patients with chronic kidney disease. Whereas higher BMI reflects both increased visceral and subcutaneous fat and/or muscle mass, a combined assessment of BMI and waist circumference may enable differentiation of visceral adiposity from muscle and/or nonvisceral fat mass. We examined the association of BMI and waist circumference with all‐cause mortality in a prospective cohort of 993 kidney transplant recipients. Associations were examined in Cox models with adjustment for demographic and comorbid conditions and for inflammatory markers. Unadjusted death hazard ratios (95%CI) associated with one standard deviation higher BMI and waist circumference were 0.94 (0.78, 1.13), p = 0.5 and 1.20 (1.00, 1.45), p = 0.05, respectively. Higher BMI was associated with lower mortality after adjustment for waist circumference (0.48 [0.34, 0.69], p < 0.001), and higher waist circumference was more strongly associated with higher mortality after adjustment for BMI (2.18 [1.55–3.08], p < 0.001). The associations of waist circumference with mortality remained significant after additional multivariable adjustments. Higher BMI and waist circumference display opposite associations with mortality in kidney transplant recipients. Waist circumference appears to be a better prognostic marker for obesity than BMI.     

Impact of Graft Infection on Long-Term Survival After Kidney Transplant

Background

Patients undergoing transplantation procedures are at a high risk of developing infections because of the need for immunosuppression. Infections presenting directly after renal transplantation greatly influence the overall success of the procedure. The aim of this study was to evaluate the influence of postoperative infection on the length of survival after renal transplant.

Methods

In 2009 a multicenter prospective trial evaluating the factors that influence the occurrence of postoperative infective complications was published by the authors. That study reported that 25 out of 232 recipients of a renal transplant were diagnosed with an infection. The present study shows the effect of postoperative infection on the length of survival after renal transplantation during a 15-year observation period. Statistical methods involved monofactorial and multifactorial Kaplan-Meier analysis for the length of survival and the Cox proportional hazards model for mortality prediction. A P value of <.05 was considered to indicate statistical significance.

Results

The analysis demonstrated that the lifespan of renal transplant recipients was decreased in those with postoperative infection, at both year 10 of the observation period (P = .013) and 15 years after transplantation (P = .012). Moreover, it was ascertained that an infection in the postoperative period was an independent risk factor increasing the mortality after renal transplantation: P = .026; hazard ratio 2.90 (95% confidence interval, 1.13–7.41).

Conclusions

The occurrence of an infection in the postoperative period significantly decreases the lifespan of a renal transplantation recipient.     

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

BackgroundThe 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 methodsThree 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.ResultsThe 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.ConclusionBeing 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.     

C-Reactive Protein and Body Mass Index Independently Predict Mortality in Kidney Transplant Recipients

C-reactive protein (CRP) is a risk factor for cardiovascular outcomes and mortality in the general population. To date, there are no prospective studies of the association between CRP and mortality or allograft loss in kidney transplant recipients (KTR). In 1995, 438 consecutive KTR were enrolled in this prospective study. Important information on demographic, clinical and immunological characteristics was collected at baseline, and CRP was measured using standard methods. Patients were then followed-up for a median 7.8 years. Time-to-event analyses (univariate and multivariate Cox proportional hazards regression models) were used to study the main outcomes: all-cause mortality and kidney allograft loss, defined as the earlier of return to dialysis, re-transplantation, or death. From univariate analyses, we found that CRP >or=0.5 mg/dL was associated with a 83% greater mortality risk compared with lower levels of this inflammatory marker [hazard ratio (HR) = 1.83; 95% confidence interval (CI): 1.23-2.72; p = 0.003]. After multivariate adjustment, patients with a CRP >or=0.5 mg/dL had a 53% higher mortality risk compared with patients whose CRP was below that threshold (HR = 1.53; 95% CI: 1.01-2.31; p = 0.04). No associations between CRP and the risk of kidney allograft loss were detected. Furthermore, we were not able to detect any effect modification between CRP and body mass index on the outcomes under study. We conclude that CRP predicts all-cause mortality, but not allograft loss in stable KTR.     

The Effect of Individual HLA Antigens on Graft Survival Rates in Kidney Transplant Patients

We have used information available in the UCLA International Transplant Registry to study the effect of HLA antigens on graft survival outcome. All results showed that of all antigens tested, the presence of DR1 in the recipient was associated with the highest graft survival rate. There was a positive matching effect for most DR antigens that were either presumed homozygous or heterozygous in the recipient. A regression analysis not only confirmed the association of DR1 and low immune response, but also suggested a greater importance of the DR rather than A or B locus to graft survival rates. Recipients with DR1,5 had the highest survival rates when DR1 was compared with other DR antigens and the heterozygous combinations of the two groups. This suggests that presence of heterozygous DR antigens may have combined effects on graft survival.     

Impact of Blood Pressure Control on Graft Survival in Kidney Transplant Recipients

BackgroundCardiovascular disease is the primary driver of morbidity and mortality in kidney transplant recipients. Hypertension is an important risk factor for development of cardiovascular disease in this population. Despite its important role in post-transplant outcomes, the blood pressure goals for kidney transplant recipients remain elusive. Current guidelines are based on observational data or data extrapolated from the chronic kidney disease population.MethodsWe followed 5-year blood pressure control of 378 kidney-alone transplant recipients at a single center and evaluated patient survival, graft survival, proteinuria, and rate of decline of kidney graft function.ResultsWe found that a mean systolic blood pressure (BP) of 121 to 130 mm Hg was associated with better graft survival, slower decline of kidney allograft function, and lower degree of proteinuria when compared with a mean systolic BP ≤120 or >130 mm Hg.ConclusionThis study provides evidence for strict blood pressure control, systolic BP between 121 and 130 mm Hg, and also cautions against intensive control of systolic BP <120 mm Hg in kidney transplant recipients.     

Repair of Achilles Tendon Rupture Using Autologous Semitendinosus Graft in a Kidney Transplant Recipient

Insertional Achilles tendon injuries can be difficult to treat when minimal tendon tissue remains for anastomosis. Moreover, in the chronic case with tendon shortening, operative repair can be more difficult than acute rupture. It is particularly desirable to reinforce the tendons, in addition to performing primary repair, in patients with renal or systemic diseases because of the accelerated collagen degeneration. Many techniques have been described for the surgical management of Achilles tendon rupture; however, none has shown clear superiority. We report the case of a 50-year-old renal transplant patient with a spontaneous distal Achilles tendon injury that we repaired using the pull-out technique reinforced with an autologous semitendinosus graft. At 2 years postoperatively, the ankle-hindfoot scale score was 92 points, and the postoperative course was without complication. We believe that the free hamstring tendon autograft is advantageous for this repair, because it is easy to handle, has limited donor site morbidity, and preserves the structures around the ankle.     

A Case Report of a Kidney Transplant Recipient With Organizing Pneumonia After Graft Loss

We present a case of a 68-year-old male patient who underwent ABO-incompatible living kidney transplantation from his wife because of immunoglobulin A nephropathy 13 years ago. Over time, the patient showed a gradual decline in graft function and required reinitiation of hemodialysis because of fluid overload, which led to his admission to our hospital. An arteriovenous fistula was created, and subsequently, hemodialysis therapy was started. Because he had chronic cytomegalovirus retinopathy and thrombotic microangiopathy due to immunosuppressive therapy at admission, mycophenolate mofetil and tacrolimus were discontinued during hemodialysis initiation. Only low-dose prednisolone was continued. One week later, the patient had a fever, and chest computed tomography revealed bilateral pneumonia, which was not improved by antibiotics. The patient was diagnosed with organized pneumonia. After ruling out opportunistic infection, including pneumocystis pneumonia, increased doses of prednisolone resulted in the remission of organizing pneumonia.     

Impact of Slow and Delayed Graft Function on Kidney Graft Survival Between Various Subgroups Among Renal Transplant Patients

Objective

Renal allografts with excellent graft function show good long-term outcomes, while grafts with delayed function have been associated with poor long-term survivals, although few reports have analyzed outcomes among these groups. We compared first-week postoperative graft function among renal transplant patients to analyze the impact of slow graft function (SGF) and delayed graft function (DGF) on graft survival.

Materials and Methods

Renal transplantations were performed from 362 unrelated, 46 related, and 163 deceased donors. Kidney transplant patients were divided into 3 groups according to their initial graft function. First-week dialyzed patients formed the DGF group. Nondialyzed patients were divided into a SGF or an excellent graft function (EGF) cohort according to whether the serum creatinine at day 7 was higher vs lower than 2.5 mg/dL, respectively.

Results

Of the 570 renal transplant recipients, DGF was observed in 39 patients (6.8%), SGF in 64 (11.2%), and EGF in 467 (81.8%). There was no significant difference in SGF vs DGF between patients who received kidneys from unrelated vs related living or deceased donors. Graft survival was worse among the DGF than the SGF or EGF patients, with no significant difference between the last 2 groups. The 6-month graft survivals were 74%, 93%, and 96%; the 3-year graft survivals were 70%, 88%, and 90%, respectively (P < .001).

Conclusions

We observed a similar impact of EGF and SGF on kidney graft survival. Kidney transplant recipients who developed DGF showed worse graft survival than those with EGF or SGF.     

Impact of Age Difference,Sex Matching,and Body Mass Index Matching Between Donor and Recipient in Renal Transplant

BackgroundVarious factors influence kidney transplant (KT) outcome. The impact of age difference between donor and recipient on long- and short-term graft and patient survival in living donor KT remains unclear.ObjectiveWe aim to determine whether age difference, sex matching, and body mass index (BMI) matching between donor and recipient affect the 12-month patient and graft survival in KT.MethodWe studied a retrospective cohort of 804 patients 18 years or older with primary KT from January 2010 to December 2014. Patient renal function and patient survival were followed up for 12 months post KT. Repeated analysis of variance measurement determined if there was a significant difference in the mean creatinine levels when the sample was grouped according to the matching groups for sex, age difference, and BMI classification. Odds ratios were computed to ascertain graft loss and graft rejection. Results were considered statistically significant if P < .05.ResultsMale donor–female recipient had the lowest creatinine levels over time compared with male donor–male recipient (P < .001) and female donor–male recipient (P < .001). Older donor–younger recipient with age difference of ≥ 15 years had the highest overall creatinine (P < .001). For BMI matching, a normal donor and an underweight recipient combination resulted in the lowest mean creatinine levels over the course of 12 months (P < .001). In terms of graft rejection, odds ratio was highest for a female donor and a male recipient (P < .00a) compared with a male donor and a female recipient. For graft loss, older donors (≥ 15 years) had the highest risk (P < .001) vs those older by 11 to 15 years.ConclusionThere was significant difference in the 12-month graft function of patients when grouped according to their matching for age difference, sex, and BMI. The risk for graft rejection increases when the combination for donor-recipient is female donor–male recipient. For graft loss, this is most significant for donors who are older by ≥ 15 years than their recipients.     

Long-Term Impact of Pretransplant and Posttransplant Diabetes Mellitus on Kidney Transplant Outcomes

Background  

The aim of this study was to compare the impact of preexisting diabetes mellitus (pre-DM), posttransplant DM (PTDM), and non-DM on the long-term outcomes of renal transplant recipients (RTRs).     

Effect of Pretransplantation Body Mass Index on Allograft Function and Patient Survival After Renal Transplantation

We evaluated the effects of pretransplantation recipient body mass index (BMI) on allograft survival and on kidney function. Kidney transplant recipients were grouped according to their pretransplantation BMIs: Group I (BMI <18.5 kg/m²; n = 10); Group II (BMI 18.5-24.9 kg/m²; n = 62); Group III (BMI 25.0-29.9 kg/m²; n = 47); and Group IV (BMI >30.0 kg/m²; n = 16). Excellent 1-year patient and graft survival rates were observed in all groups. Increased BMI was associated with increased hypertension and longer hospital stays. The incidence of acute rejection episodes, slow graft function, and delayed graft function, as well as the need for antithymocyte globulin Fresenius (ATG-F) rescue therapy were comparable between the 4 patient groups. The 1-year glomerular filtration rate was markedly different between the 4 patient groups. The 1-year posttransplantation glucose level was higher among obese patients compared with the other groups. A multivariate regression analysis confirmed the association of a higher 1-year GFR with obesity (BMI >30.0 kg/m²). Overweight and obese recipients showed excellent long-term patient and graft survival rates. Accordingly, denying patients renal transplantation because of obesity may not be justified.