Soluble transferrin receptor and soluble transferrin receptor/log ferritin index in diagnosis of iron deficiency anemia in pediatric inflammatory bowel disease

Association of soluble transferrin receptor/log ferritin index with all-cause and cause-specific mortality: National Health and Nutrition Examination Survey

Background

Soluble transferrin receptor (sTfR)/log ferritin index (sTfR Index) can be used to assess the entire spectrum of iron status, and is valuable in evaluating iron status in population studies. There is still a lack of evidence on the association between sTfR index and all-cause mortality.

Object

To explore the association between sTfR index and all-cause mortality, as well as mortality due to cardiovascular disease (CVD) and cancer.

Method

Data were from the National Health and Nutrition Examination Survey (NHANES) between 2003 to 2020. Participants aged 16 years and older who had complete data of serum ferritin and sTfR were included. Pregnant individuals or those with ineligible data on death or follow-up were excluded from the analysis. Baseline sTfR index was calculated by baseline sTfR/log (ferritin) and classified as three tertile. We performed the Cox proportional hazard regression to assess the association of sTfR index (both continuous and categorical scale) with all-cause and cause-specific mortality and further assess the non-linear relationship between sTfR index and the outcomes with restricted cubic spline.

Result

In this study, 11,525 participants, a total of 231 (2.0%) all-cause deaths occurred during a median follow-up of 51 months. The risk of all-cause mortality, CVD-related mortality, and cancer-related mortality was higher in participants with highest tertile of sTfR index. After confounding factors adjustment, participants with highest tertile of sTfR index were associated with an increased risk of all-cause mortality (HR: 1.71, 95% CI: 1.14-2.57) as compared with lowest tertile. Additionally, sTfR index per SD increment was associated with a 25% increasing risk of all-cause mortality (HR: 1.25, 95% CI: 1.08-1.45, p = 0.003) and a 38% cancer-related mortality (HR: 1.38, 95% CI: 1.07-1.77, p = 0.018). These associations remained robust after adjusting for the serum ferritin as well as in various subgroups stratified by age, sex, smoking statue, hypertension, diabetes, and CVD. Spline analysis showed that there is approximately linear relationship between sTfR index with all-cause mortality (p for non-linear = 0.481). Moreover, ferritin was not a predictor of all-cause death after adjustment for confounding factors.

Significance

This cohort study demonstrated a significant association between sTfR index increment and an increased risk of all-cause and cancer-related mortality, independent of ferritin levels.

Usefulness of Soluble Transferrin Receptor in the Diagnosis of Iron Deficiency Anemia in Rheumatoid Arthritis Patients in Clinical Practice

Aim. We analyzed the added value of sTfR measurement in routine clinical practice to standard parameters (SP) of iron deficiency in the detection of iron deficiency anemia (IDA) in patients with rheumatoid arthritis (RA). Methods. Blood samples from 116 patients with RA were analyzed in a prospective study. Based on biochemical parameters, patients were classified as having IDA, anemia of chronic disease (ACD), IDA with concomitant ACD (ACD/IDA), or “other anemia.” Sensitivity, specificity, positive (PPV), and negative predictive values (NPV) of sTfR and SP of iron status alone and in combination were calculated for the diagnosis of IDA in general, i.e., IDA or ACD/IDA. Results. In the whole sample, with regard to the diagnosis of iron deficiency (IDA or ACD/IDA), sTfR had a higher sensitivity compared both to the combined use of SP and to the combination of SP with sTfR (80.9% versus 66.7/54.8%). Specificity, PPV and NPV did not differ substantially. When patients were stratified in groups with high (CRP levels above the median, i.e., 24.1 mg/l) and low (CRP levels less or equal to the median) inflammation, the diagnostic superiority of sTfR was restricted to patients with high inflammation. In this group, the diagnostic performance of sTfR was superior both to the combined use of SP and the combination of SP with sTfR with higher sensitivity (100% versus 52.4%) and NPV (100% versus 77.7/76.7%) and comparable specificity and PPV. Conclusion. For the detection of iron depletion (IDA or ACD/IDA) in anemic RA patients, sTfR is superior to SP of iron deficiency only in highly inflammatory states.

Pathological features-based targeted delivery strategies in IBD therapy: A mini review

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is characterized by a complex and dysfunctional immune response. Currently, IBD is incurable, and patients with IBD often need to take drugs for life. However, as the traditional systemic treatment strategies for IBD do not target the site of inflammation, only limited efficacy can be obtained from them. Moreover, the possibility of serious side effects stemming from the systemic administration or redistribution of drugs in the body is high when conventional drug formulations are used. Therefore, a targeted drug-delivery system for IBD should be considered. Based on the pathological features related to IBD, the new targeted drug-delivery strategy can directly transfer the drug to the inflammatory site, thus enhancing the accumulation of the drugs and reducing side effects. This article reviews the pathological features of IBD and the application of the IBD-targeted delivery system based on different pathological features, and discusses the challenges and new prospects in this field.

Effect of Sepsis on Iron Parameters in a Population with High Prevalence of Malnutrition and Iron Deficiency: A Cross-Sectional Case-Control Pilot Study

There is lack of data on iron metabolism in critically ill sepsis children from population with high prevalence of iron deficiency (ID). The study was designed to study impact of sepsis on iron parameters in children with ID. Sepsis patients (age 6-59 months) and their apparently healthy sibling/cousin as controls were enrolled in this case-control pilot study. Serum iron, TIBC, transferrin saturation, ferritin and sTfR were measured in the two groups. sTfR-Ferritin index was calculated. Patients (n = 134) were significantly underweight compared to controls (n = 54) (WAZ score < - 2; 58% vs. 28%; p < 0.001). Serum iron and sTfR (mg/L) were lower [71.5 (51.0, 115.0) vs. 87.0 (64.5, 130.5), p = 0.068; 3.1 (2.1, 4.5) vs. 3.5 (2.8, 4.8), p = 0.026 respectively] while serum ferritin was higher [229 (94, 484.5) vs. 22 (9.2, 51); p < 0.001] in patients compared to controls. sTfR-Ferritin index was lower in patients [1.3 (0.8, 2.3) vs. 2.5 (1.8, 4.5); p < 0.001]. ROC AUC (patients vs. controls) were 0.89 (95% CI 0.83-0.95) and 0.76 (95% CI 0.68-0.85) for ferritin and sTfR-ferritin index respectively. Survivors and non-survivors were similar in terms of iron parameters. Sepsis-induced alterations in iron parameters among ID children are complex. Qualitatively it is similar (with quantitative differences) to non-ID adult population. Lack of correlation of iron parameters with mortality may be due to ID-associated immune dysfunction.

Soluble transferrin receptors and ferritin index in the diagnosis of iron deficiency in patients with spondyloarthritis and anemia

Aim. To assess the diagnostic value of the detection of soluble transferrin receptors (sTfR) and ferritin index (sTfR/log Fer) in patients with spondyloarthritis (SpA) and anemia for the revealing absolute iron deficiency (ID). Materials and methods. The study included 68 patients with SpA: median age 39 [34; 47] years, men: 38 (55.9%). Hemogram, C-reactive protein levels and ferrokinetics parameters were assessed, including sTfR testing by the method of quantitative enzyme-linked immunosorbent assay (Monobind Inc., USA). We also calculated sTfR/log Fer. Based on ferrokinetics parameters and C-reactive protein levels, chronic disease anemia (CDA), iron deficiency anemia (IDA), or their combination (CDA/IDA) were diagnosed. Results. CDA was diagnosed in 16 patients, CDA/IDA in 32 patients, and 20 patients had no anemia. An increase in sTfR concentration in patients with CDA/IDA (1.7 [1.4; 2.2] mg/L) compared with patients with CDA (1.5 [1.1; 1.7] mg/L, p0.05) was revealed. sTfR/log Fer in patients with CDA/IDA (0.93 [0.82; 1.24]) was higher than in patients with CDA (0.64 [0.48; 0.75], p0.0001). When evaluating the ROC curves, it was found that sTfR levels 1.39 mg/L and sTfR/log Fer levels 0.83 indicate the presence of absolute ID. The area under the ROC curve for sTfR was 0.72 (95% confidence interval 0.600.82, p0.001), for sTfR/log Fer 0.85 (95% confidence interval 0.740.92, p0.001). The sensitivity and specificity of sTfR/log Fer (75 and 83%, respectively) were higher compared with sTfR (53 and 81%, respectively). Conclusion. In patients with SpA having CDA/IDA, sTfR and sTfR/log Fer are statistically significantly increased. The results obtained indicate the possibility of diagnosing ID by using these parameters.

BODY IRON STATUS INDICATORS AND INFLAMMATION INDICATORS DURING INFLAMMATORY BOWEL DISEASE THERAPY IN CHILDREN AND ADOLESCENTES

BACKGROUND

The treatment of patients with inflammatory bowel disease (IBD) consists of the induction and maintenance remission of the disease. Iron status indicators would be useful for the diagnosis of iron deficiency anemia, whereas the inflammation indicators would be for the diagnosis of chronic disease anemia.

OBJECTIVE

To assess body iron status indicators and inflammation indicators during the treatment of IBD, consisted of conventional or infliximab therapy in children and adolescents.

METHODS

A case-control study of a sample of 116 individuals, of which 81 patients with IBD, 18 of them receiving conventional therapy, 20 infliximab therapy, and 43 who were in remission of the disease, and 35 healthy (control group) children and adolescents. Iron status and inflammation indicators were investigated at baseline, and 2 and 6 months of both therapies - conventional and infliximab.

RESULTS

The mean age was 12.1±4.3 years. At baseline, both groups - conventional therapy and infliximab - presented significant differences in most markers studied compared to the control group. After 2 months of conventional therapy, hemoglobin and serum iron levels were lower than those of the control group; and red cells distribution width (RDW), total iron-binding capacity, transferrin receptor/ferritin ratio, and interleukin-6 were higher than the control group. After 2 months of infliximab treatment, hemoglobin and serum iron levels were lower than those of the control group; and RDW, soluble transferrin receptor, soluble transferrin receptor/ferritin ratio, and interleukin-6 were higher than the control group. After 6 months of conventional therapy, hemoglobin and serum iron levels were lower than those of the control group, and RDW and interleukin-6 were higher than those of the control group. After 6 months of infliximab treatment, the hemoglobin and serum iron levels were lower than the control group, and RDW, soluble transferrin receptor, soluble transferrin receptor/ferritin ratio, erythrocyte sedimentation rate, and platelets were higher than the control group. Regarding patients under treatment for at least one year (remission group), all markers studied, except transferrin, were similar to the control group.

CONCLUSION

In conclusion, there were some contradictions among the different body iron status indicators and inflammation indicators at two and 6 months of treatment with conventional and infliximab therapy, however after one year of treatment, as shown by the remission group, all indicators studied, except transferrin, were similar to healthy children and adolescents.

Serum interleukin 17A and interleukin 17F in children with inflammatory bowel disease

Interleukin 17A (IL-17A) and interleukin 17F (IL-17F) appear to play important role in pathogenesis of some autoimmune diseases. However, their role in inflammatory bowel disease (IBD) has not been yet fully elucidated. We aimed to determine serum IL-17A and IL-17F in children with IBD and to assess their association with IBD activity. Recruited children underwent blood tests including complete blood count, C-reactive protein, erythrocyte sedimentation rate, IL-17A and IL-17F and stool sampling for calprotectin. The study group comprised 68 children with IBD, including 43 with ulcerative colitis and 25 with Crohn’s disease. Control group included 20 healthy children. IL-17A was significantly increased in children with IBD (median: 10.95 pg/ml; range: 0.65–200.54 pg/ml) compared to controls (median: 4.09 pg/ml; range: 0.67–26.20 pg/ml) (p = 0.002). IL-17A was significantly increased in patients with active phase of ulcerative colitis (median: 14.58 pg/ml; range: 0.65–200.54 pg/ml) compared to those in ulcerative colitis remission (median: 8.13 pg/ml; range: 1.61–58.56 pg/ml) (p = 0.04). There were no significant differences in IL-17A among patients with active and inactive Crohn’s disease (p = 0.18). IL-17F did not differ significantly between children with IBD (median: 15.11 pg/ml; range: 0.09–189.84 pg/ml) and controls (median: 11.56 pg/ml; range: 0.19–32.49 pg/ml) (p = 0.33). Our study suggests that interleukin 17A may diverse active phase from remission only in ulcerative colitis but not in Crohn’s disease.

Portuguese Consensus on Diagnosis, Treatment, and Management of Anemia in Pediatric Inflammatory Bowel Disease

Anemia is a common extraintestinal manifestation of inflammatory bowel disease (IBD), both in pediatric and in adult patients. Iron deficiency is the main cause of anemia in patients with IBD. Anemia is a clinically relevant comorbidity, with impact on patients' quality of life and it should be timely diagnosed and adequately treated. Currently, an active treatment approach is the recommended strategy, with evidence showing efficacy and safety of intravenous iron formulations. However, evidence in pediatric age remains scarce and no clinical recommendations exist for the diagnosis and treatment of this particular age group. The present document represents the first national consensus on the management of anemia in pediatric IBD and is therefore particularly relevant. The authors anticipate that the proposed recommendations will be useful in daily clinical practice for diagnosing and managing iron deficiency and iron-deficiency anemia in the pediatric population with IBD.

Comparative accuracy of ferritin, transferrin saturation and soluble transferrin receptor for the diagnosis of iron deficiency in inflammatory bowel disease

BACKGROUND

The diagnosis of iron deficiency is based on ferritin and transferrin saturation (TfS) in inflammatory bowel disease (IBD) patients, yet guideline thresholds are not evidence-based. Soluble transferrin receptor (sTfR) is one of the best noninvasive tests in patients with inflammation.

AIMS

To evaluate the accuracy of ferritin and/or TfS for diagnosing iron deficiency in IBD and identify the optimal thresholds of these parameters using sTfR as reference.

METHODS

Two hundred and two patients (2072 samples) receiving at least one infusion of biologic (vedolizumab or infliximab) were included.

RESULTS

In ulcerative colitis patients with C-reactive protein (CRP) <10 mg/L, optimal iron deficiency diagnostic performances were observed with ferritin and TfS thresholds of 65 µg/L (sensitivity of 0.78 and specificity of 0.76) and 16% (sensitivity of 0.79 and specificity of 0.90), respectively. For ulcerative colitis patients with CRP > 10 mg/L, the thresholds with the best diagnostic performance were 80 µg/L (sensitivity of 0.75 and a specificity of 0.82) for ferritin and 11% for TfS (sensitivity of 0.75 and a specificity of 0.82). There was no added value for combined ferritin and TfS. No ferritin or TfS threshold had good diagnostic performance in Crohn's disease patients (AUC for ferritin was 0.65 (95% CI 0.55-0.75) and the AUC for TfS was 0.70 (95% CI 0.61-0.78).

CONCLUSION

Ferritin and TfS are reliable parameters for iron deficiency diagnosis only in ulcerative colitis patients, at thresholds different from current guidelines. In Crohn's disease patients, sTfR should be used given the poor diagnostic performance of ferritin and TfS.

Biomarkers and Hematological Indices in the Diagnosis of Iron Deficiency in Children with Inflammatory Bowel Disease

Inflammation may affect many routinely available parameters of iron homeostasis. Thus, the recognition of iron deficiency in inflammatory bowel disease (IBD) remains a diagnostic challenge in a clinical routine. The aim of the study was to detect the most efficient marker of iron deficiency in IBD children. In a group of 75 IBD children, we evaluated the sensitivity, specificity, accuracy, and positive and negative predictive values of erythrocytes' indices, including MCV, MCH, MCHC and RDW, and biochemical markers, including iron, transferrin, sTfR and sTfR/log ferritin, for identifying iron deficiency. Receiver operating characteristic (ROC) analysis was used to compare the ability of these parameters to detect iron deficiency. The best predictors of iron deficiency were sTfR/log ferritin, with accuracy 0.86, sensitivity 0.98, specificity 0.63, positive predictive value 0.83 and negative predictive value 0.94, and sTfR, with accuracy 0.77, sensitivity 0.82, specificity 0.67, positive predictive value 0.82 and negative predictive value 0.67. Moreover, sTfR/log ferritin exhibited the largest area under ROC (0.922), followed by sTfR (0.755) and MCH (0.720). The sTfR/log ferritin index appears to be the most efficient marker of iron depletion in pediatric IBD, and it may give an added value in the management of IBD patients.