Computed tomography-based multiple body composition parameters predict outcomes in Crohn’s disease

Abstract

Background The efficacy of computed tomography-based multiple body composition parameters in assessing disease behavior and prognosis has not been comprehensively evaluated in Crohn’s disease. This study aimed to assess the association of body composition parameters with disease behavior and outcomes in Crohn’s disease and to compare the efficacies of indexes derived from body and lumbar spinal heights in body composition analysis. Results One hundred twenty-two patients with confirmed Crohn’s disease diagnoses and abdominal computed tomography scans were retrospectively included in this study. Skeletal muscle, visceral, and subcutaneous fat indexes were calculated by dividing each type of tissue area by height2 and lumbar spinal height2. Parameters reflecting the distribution of adiposity were also assessed. Principal component analysis was used to deal with parameters with multicollinearity. Patients were grouped according to their disease behavior (inflammatory vs. structuring/penetrating) and outcomes. Adverse outcome included need for intestinal surgery or anti-TNF therapy. Predictors of disease course from multiple parameters were evaluated using multivariate analysis. Indexes derived from body and lumbar spinal heights were strongly correlated (r, 0.934–0.995; p < 0.001). Low skeletal muscle-related parameters were significantly associated with complicated disease behavior in multivariate analysis (p = 0.048). Complicated disease behavior (p < 0.001) and adipose tissue parameters-related first principal component (p = 0.029) were independent biomarkers for predicting adverse outcomes. Conclusions Skeletal muscle and adipose tissue principle component were associated with complicated Crohn’s disease behavior and adverse outcome, respectively. Indexes derived from body and lumbar spinal heights have similar efficacies in body composition analysis.

The relationship between perianal fistula activity and abdominal adipose tissue in Crohn’s disease: an observational study

“…Therefore, VAT density is not only a distinguishing indicator of CD activity, but also reflects perianal fistula activity to some extent. In Thiberge's study [21], CD patients with low SAI and VAI were at greater risk of adverse outcomes, which is supported by Zhou's results [22]. And the latter proposed standardizing SAT and VAT area with L1-L5 vertebral height instead of height to reduce reliance on clinical data, and the new standardized indexes obtained proved to be highly relevant to the traditional method.…”

“…Feng et al found that the λ HU of creeping fat (CF) in CD patients increased with the severity of intestinal inflammation, and the λ HU of CF around the intestinal segments without lesions was significantly higher than that in the controls [ 20 ]. Zhou et al showed an increased risk of poor prognosis in CD patients with high SAT and VAT density [ 22 ]. Similarly, we observed higher VAT density at all levels in the high activity group ( p < 0.01).…”

“…In order to avoid the influence of absolute content parameters on conclusions, many studies have introduced relative content parameters Previous studies have shown that VSR or VA/TA index in CT images are higher in aggressive CD or patients with adverse outcomes [ 18 , 22 ]; Buning et al also found that high VAT/FM (total fat mass) ratio (the ratio of VAT to total body fat mass, similar to VA/TA index) was associated with more complex behaviors and higher activity by using MRI [ 30 ]. Moreover, in Bryant's study, in addition to finding higher VSR in patients with low life quality, they also found a positive correlation between VSR and stricturing disease behavior in ileocolonic CD patients [ 31 ].…”

“…The average cross-sectional area and average density (Hounsfield unit, HU) of SAT and VAT were measured, respectively. The standardized indices subcutaneous adipose index (SAI) and visceral adipose index (VAI) were obtained by dividing the area of SAT and VAT by height L1-5 squared [ 22 ]. The VAT/SAT ratio (VSR) and VAT/Total adipose tissue (VA/TA) index were also calculated to reflect the proportion of VAT.…”

“…In addition, the combination of anatomical features in the images allows researchers to quantify the same tissue in different regions separately, for example subcutaneous adipose tissue (SAT) and VAT. Although there is a growing number of studies using CT-based fat parameters for the analysis of disease activity and prognosis in CD patients [20][21][22], no researcher has confirmed the difference in these parameters among patients with different perianal fistula activity. In addition, no clear evidence could be found to confirm the relationship between perianal fistula and overall disease activity.…”