Inferior outcomes for overweight children undergoing allogeneic stem cell transplantation

Impact of body mass index at diagnosis on outcomes of pediatric acute leukemia: A systematic review and meta-analysis

BACKGROUND

The incidence of childhood malnutrition i.e., both obesity and undernutrition, is on a rise. While there is extensive evidence of the influence of body mass index (BMI) on the survival and other important outcomes of adult cancers, the impact of childhood BMI on one of the common pediatric cancers i.e., leukemia is not well studied.

METHODS

Systematic search of PubMed, Scopus, and Google Scholar databases was done to identify studies that were conducted among pediatric patients with leukemia and had examined outcomes of interest based on BMI at the time of diagnosis.

RESULTS

Effect sizes were reported as pooled hazards ratio (HR) along with 95% confidence intervals (CI). A total of 17 studies were included. Compared to pediatric leukemia patients with normal BMI, underweight (HR 1.07, 95% CI: 1.04, 1.11) and obese (HR 1.42, 95% CI: 1.18, 1.71) children with leukemia had higher risks of overall mortality. Underweight (HR 1.10, 95% CI: 1.02, 1.19) and obese (HR 1.34, 95% CI: 1.15, 1.55) pediatric leukemia patients had a tendency to lower event-free survival compared to children with normal BMI. The risk of relapse was not significant for underweight, overweight, and obese children.

CONCLUSIONS

Both underweight and obese status at the time of diagnosis were associated with poor survival outcomes in pediatric patients with leukemia.

Pre-Transplant Serum Leptin Levels and Relapse of Acute Myeloid Leukemia after Allogeneic Transplantation

Weight loss and metabolic activity influence outcome after allogeneic stem cell transplantation (alloSCT). This study evaluates pre-conditioning Leptin, a peptide hormone involved in metabolism and immune homeostasis, as a prognostic factor for survival, relapse and non-relapse mortality (NRM) following alloSCT. Leptin serum levels prior to conditioning were determined in a cohort of patients transplanted for various hematologic malignancies (n = 524) and correlated retrospectively with clinical outcome. Findings related to patients with acute leukemia (AL) from this sample were validated in an independent cohort. Low pre-conditioning serum Leptin was an independent prognostic marker for increased risk of relapse (but not of NRM and overall mortality) following alloSCT for AL of intermediate and advanced stage (beyond first complete remission). Multivariate analysis revealed a hazard ratio (HR) for relapse of 0.75 per log2 increase (0.59–0.96, p = 0.020). This effect was similar in an independent validation cohort. Pre-conditioning serum Leptin was validated as a prognostic marker for early relapse by fitting the multivariate Cox model to the validation data. Pre-conditioning serum Leptin levels may serve as an independent prognostic marker for relapse following alloSCT in intermediate and advanced stage AL patients. Prospective studies are required to prove whether serum Leptin could be used for guiding nutritional intervention in patients with AL undergoing alloSCT.

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.

Pediatric hematopoietic cell transplantation: Longitudinal trends in body mass index and outcomes

Pediatric recipients of HCT may have a high susceptibility for overweight and obesity, and obesity may negatively impact post-transplant mortality and survival. This is a single-center retrospective analysis of 297 pediatric patients who received HCT between 2005 and 2018. Patients were classified as UW, NW, OW, or OB based on age-adjusted BMI. A mixed-effects linear regression model controlling for patient, disease, and transplant-related characteristics was used to trend weight longitudinally. Comparisons were made between weight category and post-transplant outcomes. In the pretransplant period, 5.4%, 54.5%, 22.2%, and 17.8% of patients were UW, NW, OW, and OB, respectively. Five years post-transplantation, those numbers were 10.6%, 48.2%, 16.5%, and 24.7%. Overall, BMI increased 0.00094 ± 0.0001 kg/m² each day post-transplant (P < .001), with older individuals demonstrating greater rates of increase. Further, there was a larger BMI increase in patients without TBI compared with those who received TBI (1.29 ± 0.49, P = .008). Rates of acute GVHD, chronic GVHD, and viral infections, in addition to time to platelet and neutrophil engraftment and 5-year survival estimates, were not significantly different based on pretransplant BMI. Overweight and obese individuals had poorer 5-year survival based on 100-day post-transplant BMI (P = .02). Overall, pediatric HCT recipients are at risk of developing obesity, which is associated with decreased survival. Adolescents and young adults demonstrate the highest risk of weight gain, representing a vulnerable population that requires close monitoring, additional interventions, and further research.

A Review on the Impact of Body Mass Index on Outcomes in Pediatric Leukemia

In the last decades, adults and pediatric obesity have become a major issue in developed countries. Considerable research has been conducted in patients with acute lymphoblastic (ALL) and myeloid leukemia (AML) with the aim of correlating body mass index (BMI) and outcomes in patients undergoing chemotherapy for hematological diseases. In adults, a high BMI has been associated with increased leukemia-related mortality. Whether a similar effect exists in the pediatric setting remains controversial. Some of the studies detailed in this review have reported no differences in outcomes according to BMI, whilst other reports have described higher treatment-related mortality, increased risk of relapse and death. Although the link between BMI and acute leukemia outcomes is controversial, a large number of studies describe poorer survival rates in children with AML or ALL with higher BMI. On the other hand, being underweight has been associated with higher treatment-related toxicity. Understanding more about the impact of BMI in pediatric leukemia is of utmost importance to provide prompt intervention and improve outcomes.

Obesity and Pediatric Drug Development

There is a lack of dosing guidelines for use in obese children. Moreover, the impact of obesity on drug safety and clinical outcomes is poorly defined. The paucity of information needed for the safe and effective use of drugs in obese patients remains a problem, even after drug approval. To assess the current incorporation of obesity as a covariate in pediatric drug development, the pediatric medical and clinical pharmacology reviews under the Food and Drug Administration (FDA) Amendments Act of 2007 and the FDA Safety and Innovation Act (FDASIA) of 2012 were reviewed for obesity studies. FDA labels were also reviewed for statements addressing obesity in pediatric patients. Forty-five drugs studied in pediatric patients under the FDA Amendments Act were found to have statements and key words in the medical and clinical pharmacology reviews and labels related to obesity. Forty-four products were identified similarly with pediatric studies under FDASIA. Of the 89 product labels identified, none provided dosing information related to obesity. The effect of body mass index on drug pharmacokinetics was mentioned in only 4 labels. We conclude that there is little information presently available to provide guidance related to dosing in obese pediatric patients. Moving forward, regulators, clinicians, and the pharmaceutical industry should consider situations in drug development in which the inclusion of obese patients in pediatric trials is necessary to facilitate the safe and effective use of new drug products in the obese pediatric population.

Body Mass Index at Pediatric Leukemia Diagnosis and the Risks of Relapse and Mortality: Findings from a Single Institution and Meta-analysis

High body mass index (BMI) is associated with relapse of certain adult cancers, but limited knowledge exists on its association with pediatric leukemia relapse. We evaluated the association between overweight/obesity (BMI ≥ 85^th percentile) at pediatric leukemia diagnosis and relapse or mortality. A meta-analysis combining our findings with those of previous studies was also performed. The study included 181 pediatric leukemia patients. Sporadic missing data were multiply imputed, and hazard ratios (HR) and 95% confidence intervals (95% CI) were calculated using Cox proportional hazard. Age- and sex-adjusted analysis for patients ≥10 years showed a trend towards increased risk of relapse for overweight/obese patients (HR = 2.89, 95% CI = 0.89-9.36, p=0.08) that was not evident among children<10 years (HR = 0.52, 95% CI = 0.08-3.54, p=0.49). We observed a statistically significant association between mortality and obesity status in unadjusted models (imputed: HR = 2.54, 95% CI = 1.15-5.60, p=0.021; complete set: HR = 2.72, 95% CI = 1.26-5.91, p=0.011) that was not statistically significant in both age- and sex-adjusted and multivariable adjusted analyses. The pooled estimate of our finding and previous studies showed an association between overweight/obese and increased risk of mortality for ALL (HR = 1.39, 95% CI = 1.16-1.46) and AML (HR = 1.64, 95% CI = 1.32-2.04). Although our study did not observe statistically significant associations due to a small sample size, the meta-analyses revealed an increased risk of mortality for overweight/obese patients. The findings of our study suggest an association of obesity status with relapse in children ≥10 years. However, our study was based on a small sample size from a single institution, and this association needs to be investigated in larger, multicenter studies.

Baseline body mass index among children and adults undergoing allogeneic hematopoietic cell transplantation: clinical characteristics and outcomes

Obesity is an important public health problem that may influence the outcomes of hematopoietic cell transplantation (HCT). We studied 898 children and adults receiving first-time allogeneic hematopoietic SCTs between 2004 and 2012. Pretransplant body mass index (BMI) was classified as underweight, normal weight, overweight or obese using the WHO classification or age-adjusted BMI percentiles for children. The study population was predominantly Caucasian, and the median age was 51 years (5 months-73 years). The cumulative 3-year incidence of nonrelapse mortality (NRM) in underweight, normal weight, overweight and obese patients was 20%, 19%, 20% and 33%, respectively. Major causes of NRM were acute and chronic GVHD. The corresponding incidence of relapse was 30%, 41%, 37% and 30%, respectively. Three-year OS was 59%, 48%, 47% and 43%, respectively. Multivariate analysis showed that obesity was associated with higher NRM (hazard ratio (HR) 1.43, P=0.04) and lower relapse (HR 0.65, P=0.002). Pretransplant plasma levels of ST2 and TNFR1 biomarkers were significantly higher in obese compared with normal weight patients (P=0.04 and P=0.05, respectively). The increase in NRM observed in obese patients was partially offset by a lower incidence of relapse with no difference in OS.

Effect of body mass in children with hematologic malignancies undergoing allogeneic bone marrow transplantation

The rising incidence of pediatric obesity may significantly affect bone marrow transplantation (BMT) outcomes. We analyzed outcomes in 3687 children worldwide who received cyclophosphamide-based BMT regimens for leukemias between 1990 and 2007. Recipients were classified according to age-adjusted body mass index (BMI) percentiles as underweight (UW), at risk of UW (RUW), normal, overweight (OW), or obese (OB). Median age and race were similar in all groups. Sixty-one percent of OB children were from the United States/Canada. Three-year relapse-free and overall survival ranged from 48% to 52% (P = .54) and 55% to 58% (P = .81) across BMI groups. Three-year leukemia relapses were 33%, 33%, 29%, 25%, and 21% in the UW, RUW, normal, OW, and OB groups, respectively (P < .001). Corresponding cumulative incidences for transplant-related mortality (TRM) were 18%, 19%, 21%, 22%, and 28% (P < .01). Multivariate analysis demonstrated a decreased risk of relapse compared with normal BMI (relative risk [RR] = 0.73; P < .01) and a trend toward higher TRM (RR = 1.28; P = .014). BMI in children is not significantly associated with different survival after BMT for hematologic malignancies. Obese children experience less relapse posttransplant compared with children with normal BMI; however, this benefit is offset by excess in TRM.

Association between baseline body mass index and overall survival among patients over age 60 with acute myeloid leukemia

Acute myeloid leukemia (AML) is more common and more lethal among patients over the age of 60. Increased body mass index (BMI) has been associated with a higher incidence of various malignancies, including AML. We sought to determine whether patient BMI at the time of AML diagnosis is related to overall survival (OS) among elderly patients. We identified 97 patients with AML diagnosed after the age of 60 and treated with cytarabine-based induction chemotherapy. The median age was 68 years (range 60-87); 52% of patients were male, and our study population was predominantly white (89% of patients). The median OS for all patients was 316 days (95% CI 246-459). The hazard ratio for mortality was increased among patients with a BMI < 25 compared to BMI ≥ 30 (HR 2.14, P = 0.009, 95% CI 1.21-3.77), as well as with older age (HR 1.76, P = 0.015, 95% CI 1.12-2.79) and with secondary versus de novo disease (HR 1.95, P = 0.006, 95% CI 1.21-3.14). After multivariable analysis, we did not find a significant association between OS and other potential confounders such as coronary artery disease or diabetes among these patients. We conclude that increased BMI was independently associated with improved OS among older AML patients at our institution.

Influence of obesity on clinical outcomes in hospitalized children: a systematic review

IMPORTANCE

Obesity is prevalent among hospitalized children. Knowledge of the relationship between obesity and outcomes in hospitalized children will enhance nutrition assessment and provide opportunities for interventions.

OBJECTIVE

To systematically review the existing literature concerning the impact of obesity on clinical outcomes in hospitalized children.

EVIDENCE ACQUISITION

PubMed, Web of Science, and EMBASE databases were searched for studies of hospitalized children aged 2 to 18 years with identified obesity and at least 1 of the following clinical outcomes: all-cause mortality, incidence of infections, and length of hospital stay. Cohort and case-control studies were included. Cross-sectional studies, studies of healthy children, and those without defined criteria for classifying weight status were excluded. The Newcastle-Ottawa Scale was used to assess study quality.

RESULTS

Twenty-eight studies (26 retrospective; 24 cohort and 4 case-control) were included. Of the 21 studies that included mortality as an outcome, 10 reported a significant positive relationship between obesity and mortality. The incidence of infections was assessed in 8 of the 28 studies; 2 reported significantly more infections in obese compared with nonobese patients. Of the 11 studies that examined length of stay, 5 reported significantly longer lengths of hospital stay for obese children. Fifteen studies (53%) had a high quality score. Larger studies observed significant relationships between obesity and outcomes. Studies of critically ill, oncologic or stem cell transplant, and solid organ transplant patients showed a relationship between obesity and mortality.

CONCLUSIONS AND RELEVANCE

The available literature on the relationship between obesity and clinical outcomes is limited by subject heterogeneity, variations in criteria for defining obesity, and outcomes examined. Childhood obesity may be a risk factor for higher mortality in hospitalized children with critical illness, oncologic diagnoses, or transplants. Further examination of the relationship between obesity and clinical outcomes in this subgroup of hospitalized children is needed.

Childhood obesity and outcomes after bone marrow transplantation for patients with severe aplastic anemia

The prevalence of obesity in the pediatric population has increased in the last 2 decades and represents a serious health concern, with potential impact on outcomes of hematopoietic cell transplantation (HCT). We studied the effect of weight by age-adjusted body mass index (BMI) percentile in 1,281 pediatric patients (age 2-19 years) with severe aplastic anemia who underwent HCT between 1990 and 2005. The study population was divided into 5 weight groups-underweight, risk of underweight, normal BMI range, risk of overweight, and overweight-according to age-adjusted BMI percentiles. Cox proportional hazards regression models for survival and acute graft-versus-host disease (aGVHD), performed using weight groups as the main effect and the normal BMI range (26th-75th percentile) as the baseline comparison, found higher mortality among overweight children (>95th percentile adjusted for age). Weight at transplantation did not increase the adjusted risk of grade III-IV aGVHD. The 1-year and 2-year overall survival rates were 60% and 59% for overweight children, compared with >70% in children with lower BMI at both time points (P < .001). Other significant factors associated with survival included race and region, donor type, conditioning regimens in related donor transplants, performance score, and year of transplantation. In conclusion, overweight children with aplastic anemia have worse outcomes after HCT. The impact of obesity on survival outcomes in children should be discussed during pretransplantation counseling.