Paediatric reference values for total psoas muscle area

Sarcopenia is a Predictor for Adverse Clinical Outcome in Pediatric Inflammatory Bowel Disease

OBJECTIVES

Inflammatory bowel disease (IBD) has a high impact on nutritional status. Sarcopenia is related to higher risk of surgery and rescue therapy in adults with IBD; however, comparable data in pediatric populations are scarce. We evaluated muscle mass as a predictor of disease outcome in pediatric IBD.

METHODS

All pediatric IBD patients who underwent magnetic resonance enterography (MRE) during 2008 to 2019 were included. Muscle mass was assessed by measuring the area of the psoas muscle at the upper level of L3 on MRE. The psoas area divided by the body surface area (BSA) yielded the psoas index. Clinical and radiological data, including disease location, activity, course, and medications were documented. The control group included non-IBD children who underwent an MR imaging study.

RESULTS

We enrolled 101 IBD patients, 69 (68.3%) with Crohn disease (CD) and 32 (31.7%) with ulcerative colitis (UC) (mean age 15.03 ± 3.27 years). The psoas index was significantly lower in the IBD patients compared with the 87 controls (326 vs 528, respectively, P < 0.001). Patients with a psoas index in the lowest quartile had significantly higher risk for biologic therapy (multivariate analysis, hazard ratio [HR] = 12.1, P = 0.046) and disease exacerbation (HR = 9, P = 0.047) independently of body mass index, compared with patients with a psoas index in the uppermost quartile.

CONCLUSIONS

Sarcopenia correlates with the radiological severity of pediatric IBD and serves as a predictor for adverse clinical disease outcome. Muscle mass measurement in MRE studies may serve as a possible marker for disease outcome in this population.

Sarcopenia is a prognostic outcome marker in children with high-risk hepatoblastoma

BACKGROUND

Children with hepatoblastoma (HB) are at risk of sarcopenia due to immobility, chemotherapy, and malnutrition. We hypothesized that children with HB have a low preoperative total psoas muscle area (tPMA), reflecting sarcopenia, which negatively impacts outcome.

PROCEDURE

Retrospective study of children (1-10 years) with hepatoblastoma treated at a large university children's hospital from 2009 to 2018. tPMA was measured as the sum of the right and left psoas muscle area (PMA) at intervertebral disc levels L3-4 and L4-5. z-Scores were calculated using age- and gender-specific reference values and were compared to anthropometric measurements, clinical variables, and outcomes. Sarcopenia was defined as a tPMA z-score below -2.

RESULTS

Thirty-three children were included. Mean tPMA z-score was -2.18 ± 1.08, and 52% were sarcopenic. A poor correlation between tPMA and weight was seen (r = 0.35; confidence interval [CI] 0.01, 0.62; P = .045), and most children had weights within the normal range (mean z-score -0.55 ± 1.39). All children categorized as high risk with relapse (n = 5/12) were sarcopenic before surgery. Relapse was significantly higher in the high-risk sarcopenic group compared to the nonsarcopenic group (P = .008). The change in tPMA z-score 1-4 months after surgery did not improve in patients with relapse, but did improve in 75% of children without relapse.

CONCLUSIONS

The majority of children with HB were sarcopenic prior to surgery. Especially in children with high-risk hepatoblastoma, sarcopenia is an additional risk factor for relapse. Large multicenter studies are needed to confirm these preliminary results.

Sarcopenia in Children With End-Stage Liver Disease on the Transplant Waiting List

Sarcopenia predicts morbidity and mortality in adults with end-stage liver disease (ESLD) and is determined by total psoas muscle area (tPMA) measurement from computed tomography (CT) imaging. Recently developed pediatric age- and sex-specific tPMA growth curves provide the opportunity to ascertain prevalence and impact of sarcopenia in children awaiting liver transplantation (LT). This retrospective single-center study evaluated sarcopenia in children between 1 and 16 years with ESLD and a clinically indicated abdominal CT less than 3 months before first isolated LT. Sarcopenia was defined as tPMA z score less than -2 measured at the intervertebral L4-5 level. Patient demographic, biochemical, and outcome data were recorded. tPMA was compared with other measures of nutritional status using univariate and multivariate logistic analyses. Outcome measures included 1-year morbidity events and mortality after LT. CT images from 25 (64% female) children with median age of 5.50 (interquartile range [IQR], 3.75-11.33) years were reviewed. Ten children (40%) had a tPMA z score less than -2. Sarcopenia was associated with lower z scores for weight (odds ratio [OR], 0.38; P = 0.02), height (OR, 0.32; P = 0.03), and nutritional support before LT (OR, 12.93; P = 0.01). Sarcopenic children had a longer duration of pediatric intensive care unit (PICU) stay (3.50 [IQR, 3.00-6.00] versus 2.00 [IQR, 2.00-3.50] days; P = 0.03). Sarcopenia was prevalent in 40% of children with ESLD awaiting LT, and lower tPMA z score was associated with deficient anthropometrics and need for nutritional support before LT. Post-LT PICU duration was increased in children with sarcopenia, reflecting adverse outcomes associated with muscle loss. Further studies are needed to elucidate the underlying mechanisms of sarcopenia in children with ESLD.

Routine abdominal magnetic resonance imaging can determine psoas muscle area in paediatric Crohn's disease and correlates with bioelectrical impedance spectroscopy measures of lean mass

BACKGROUND

Paediatric Crohn's disease (CD) has been associated with undernutrition. Accurate and accessible measures of body composition would provide data to personalise nutritional therapy. We assessed feasibility of MRI-derived measures of psoas cross-sectional area (PCSA) in paediatric CD and correlated with anthropometric and bioelectrical impedance spectroscopy (BIS) measures.

METHODS

MRI small bowel/pelvis images of patients with CD, aged <18 years, were retrieved. Patients with concurrent anthropometric and BIS measurements were eligible for inclusion. The PCSA at L3 was calculated by two assessors and combined. To assess reproducibility of measures we calculated the coefficient of variation (CoV). Age, height-Z-scores, weight-Z-scores and BIS measures were correlated with PCSA. Using normal paediatric data from CT-scans we derived psoas area Z-scores for our cohort.

RESULTS

10 patients were included. Mean age at MRI scan was 14.6 years (11.7-16.3). PCSA was calculated for all MRI scans. There was high reproducibility between measurers, mean CoV 0.099. There was a significant positive correlation between PCSA and BIA-derived fat free mass, Pearson correlation coefficient (PCC) 0.831, p = 0.003. Correlation coefficients for PCSA and Height-for-age Z-score, weight-for-age -Z-score and age were PCC 0.343- p = 0.33, PCC = 0.222- p = 0.54, and PCC 0.6034- p = 0.065, respectively. The mean PCSA Z-score was -1.81, with 70% of the patients having a Z-score < -2.0.

CONCLUSIONS

These data demonstrate the feasibility of deriving measures of body composition from routine MRI imagine. There was significant positive correlation between PCSA and BIS-derived lean mass. Further studies are required to confirm applicability of normal ranges prior to routine clinical implementation.

Establishing Reference Values for Lean Muscle Mass in the Pediatric Patient

OBJECTIVES

Adults with decreased muscle mass experience worse outcomes and more frequent complications. The effects of sarcopenia on pediatric outcomes are unknown. Our objective was to define reference values for lean muscle mass in a healthy pediatric population to facilitate future studies on the impact of lean muscle mass on pediatric outcomes.

PATIENTS AND METHODS

Bilateral psoas muscle surface area was measured by computed tomography in a healthy pediatric population undergoing evaluation after trauma. Pearson correlation coefficients (PCCs) were calculated for age, weight, height, body mass index (BMI), total psoas muscle area, and psoas muscle index (PMI; defined as psoas muscle area divided by height squared). Quantile regression was used to determine age- and sex-specific percentiles of psoas muscle area and PMI.

RESULTS

Analysis of 494 male and 288 female patients with available imaging (median age: 9.3 years, interquartile range: 5.4-13.4; 63.1% male) was performed. For males, age correlated strongly with total psoas volume (PCC = 0.87), height (0.95), and weight (0.88) and poorly with BMI (0.45). In females, age correlated strongly with total psoas volume (0.88), height (0.92), weight (0.88) and poorly with BMI (0.19). Gender-specific curves and charts were created using output from the quantile regression from reference values of the total psoas muscle area corresponding to the 25th, 50th, and 75th percentiles across all ages.

CONCLUSIONS

We created gender-specific reference charts for total and height-normalized psoas muscle area in healthy children based on age. These results can be used in future studies to establish the effects of sarcopenia in pediatric patients.

Body Composition of Infants With Biliary Atresia: Anthropometric Measurements and Computed Tomography-based Body Metrics

OBJECTIVES

Biliary atresia (BA) causes neonatal cholestasis that requires hepatoportoenterostomy or liver transplantation (LT) for long-term survival. Nutritional optimization is necessary as sarcopenia and sarcopenic obesity have been associated with adverse clinical outcome. Currently, mid upper arm circumference (MUAC) is considered the most accurate indicator. The aim of the study was to determine computed tomography (CT)-based body metrics in infants with BA and to evaluate its correlation with MUAC.

METHODS

We retrospectively analyzed all BA infants below 2 years of age who underwent CT as part of LT screening at our hospital between 2006 and 2019. Measured variables were indexed with length and included: MUAC, total psoas muscle surface area (tPMSA), cross-sectional skeletal muscle area (CSMA), and total abdominal fat area. Intraclass correlation coefficients and Pearson coefficients were calculated. CSMA-to-abdominal fat area ratio was divided in quartiles, the lowest quartile group was considered sarcopenic obese.

RESULTS

Eighty infants with a median age of 4.6 months at LT screening were included. Intraclass correlation coefficients were: tPMSA = 0.94, CSMA = 0.92, and total abdominal fat area = 0.99. Correlation between MUAC z-score and indices of tPMSA, CSMA, and total abdominal fat area were r = 0.02, r = 0.06, and r = 0.43, respectively. The cut-off for sarcopenic obesity was CSMA-to-abdominal fat area ratio below 0.93.

CONCLUSIONS

In BA infants, it is possible to determine CT-based body metrics during LT screening with very strong interobserver agreement. Poor correlation between CT-based body metrics and MUAC suggests that CT-based body metrics provide additional information on body composition in BA infants, such as relative muscle mass.

Paediatric reference values for total psoas muscle area

BACKGROUND

Sarcopenia, the unintentional loss of skeletal muscle mass, is associated with poor outcomes in adult patient populations. In adults, sarcopenia is often ascertained by cross-sectional imaging of the psoas muscle area (PMA). Although children with chronic medical illnesses may be at increased risk for muscle loss because of nutritional deficiencies, physical deconditioning, endocrine anomalies, and systemic inflammation, consistent quantitative definitions for sarcopenia in children are lacking. We aimed to generate paediatric reference values for PMA at two intervertebral lumbar levels, L3-4 and L4-5.

METHODS

In this cross-sectional study, we analysed abdominal computed tomography scans of consecutive children presenting to the emergency department. Participants were children 1-16 years who required abdominal cross-sectional imaging after paediatric trauma between January 1, 2005 and December 31, 2015 in a large Canadian quaternary care centre. Children with a documented chronic medical illness or an acute spinal trauma at presentation were excluded. Total PMA (tPMA) at levels L3-4 and L4-5 were measured in square millimetres (mm² ) as the sum of left and right PMA. Age-specific and sex-specific tPMA percentile curves were modelled using quantile regression.

RESULTS

Computed tomography images from 779 children were included. Values of tPMA at L4-5 were significantly larger than at L3-4 at all ages, but their correlation was high for both girls (r = 0.95) and boys (r = 0.98). Amongst girls, tPMA 50th percentile values ranged from 365 to 2336 mm² at L3-4 and from 447 to 2704 mm² for L4-5. Amongst boys, 50th percentile values for tPMA ranged between 394 and 3050 mm² at L3-4 and from 498 to 3513 mm² at L4-5. Intraclass correlation coefficients were excellent at L3-4 (0.97, 95% CI 0.94 to 0.981) and L4-5 (0.99, 95% CI 0.986 to 0.995). Weight and tPMA were correlated, stratified by sex for boys (L3-4 r = 0.90; L4-5 r = 0.90) and for girls (L3-4 r = 0.87; L4-5 r = 0.87). An online application was subsequently developed to easily calculate age-specific and sex-specific z-scores and percentiles.

CONCLUSIONS

We provide novel paediatric age-specific and sex-specific growth curves for tPMA at intervertebral L3-4 and L4-5 levels for children between the ages of 1-16 years. Together with an online tool (https://ahrc-apps.shinyapps.io/sarcopenia/), these tPMA curves should serve as a reference enabling earlier identification and targeted intervention of sarcopenia in children with chronic medical conditions.