[Posted 11/Nov/2022]

AUDIENCE: Nephrology, Internal Medicine

KEY FINDINGS: Although NMR-quantified metabolites did not improve discrimination, several urine metabolic profiles were identified that may improve understanding of kidney stone pathogenesis.

BACKGROUND: The urine metabolites and chemistries that contribute to kidney stone formation are not fully understood. This study examined differences between the urine metabolic and chemistries profiles of first-time stone formers and controls.

DETAILS: High-resolution ¹H-nuclear magnetic resonance (NMR) spectroscopy-based metabolomic analysis was performed in 24-hour urine samples from a prospective cohort of 418 first-time symptomatic kidney stone formers and 440 controls. In total, 48 NMR-quantified metabolites in addition to 12 standard urine chemistries were assayed. Analysis of covariance was used to determine the association of stone former status with urine metabolites or chemistries after adjusting for age and sex and correcting for the false discovery rate. Gradient-boosted machine methods with nested cross-validation were applied to predict stone former status. Among the standard urine chemistries, stone formers had lower urine oxalate and potassium and higher urine calcium, phosphate, and creatinine. Among NMR urine metabolites, stone formers had lower hippuric acid, trigonelline, 2-furoylglycine, imidazole, and citrate and higher creatine and alanine. A cross-validated model using urine chemistries, age, and sex yielded a mean AUC of 0.76 (95% CI, 0.73 to 0.79). A cross-validated model using urine chemistries, NMR-quantified metabolites, age, and sex did not meaningfully improve the discrimination (mean AUC, 0.78; 95% CI, 0.75 to 0.81). In this combined model, among the top ten discriminating features, four were urine chemistries and six NMR-quantified metabolites.

Copyright © American Society of Nephrology. All rights reserved.

Source: Thongprayoon, C., Vuckovic, I., Vuckovic, L. E., et al. (2022). Nuclear Magnetic Resonance Metabolomic Profiling and Urine Chemistries in Incident Kidney Stone Formers Compared with Controls. JASN. 2022, 33(11): 2071-2086. Published: November, 2022. DOI: 10.1681/ASN.2022040416.

A Systematic Review and Meta-Analysis

[Posted 1/Mar/2024]

AUDIENCE: Nephrology, Internal Medicine

KEY FINDINGS: Lower eGFR and greater albuminuria were independently associated with increased risk of incident AF. CKD should be regarded as an independent risk factor for incident AF.

BACKGROUND: Atrial fibrillation (AF) and chronic kidney disease (CKD) often coexist. However, it is not known whether CKD is an independent risk factor for incident AF. Therefore, we evaluated the association between markers of CKD-estimated glomerular filtration rate (eGFR) and albuminuria-and incident AF.

DETAILS: Participants with measurement of eGFR and/or albuminuria who were not receiving dialysis.Selection Criteria for Studies: Cohort studies and randomized controlled trials were included that reported incident AF risk in adults according to eGFR and/or albuminuria. Age- or multivariate-adjusted risk ratios (RRs) for incident AF were extracted from cohort studies, and RRs for each trial were derived from event data. RRs for incident AF were pooled using random-effects models. 38 studies involving 28,470,249 participants with 530,041 incident AF cases were included. Adjusted risk of incident AF was greater among participants with lower eGFR than those with higher eGFR (eGFR <60 vs >=60 mL/min/1.73 m²: RR, 1.43; 95% CI, 1.30-1.57; and eGFR <90 vs >=90 mL/min/1.73 m²: RR, 1.42; 95% CI, 1.26-1.60). Adjusted incident AF risk was greater among participants with albuminuria (any albuminuria vs no albuminuria: RR, 1.43; 95% CI, 1.25-1.63; and moderately to severely increased albuminuria vs normal to mildly increased albuminuria: RR, 1.64; 95% CI, 1.31-2.06). Subgroup analyses showed an exposure-dependent association between CKD and incident AF, with the risk increasing progressively at lower eGFR and higher albuminuria

Copyright © Elsevier Ltd. All rights reserved.

Source: Ha, J. T., Freedman, S. B., Kelly, D. M., et al. (2024). Kidney Function, Albuminuria, and Risk of Incident Atrial Fibrillation: A Systematic Review and Meta-Analysis. American Journal of Kidney Diseases. Published: March, 2024. DOI: 10.1053/j.ajkd.2023.07.023.

A Long-term Follow-up Study

[Posted 26/Feb/2024]

AUDIENCE: Endocrinology, Nephrology

KEY FINDINGS: Impaired glucose tolerance and reduced early-phase insulin response to glucose are involved in the development of new-onset diabetes after DP; the latter is an additional factor in the development of diabetes and becomes apparent when pancreatic beta cell mass is reduced after DP.

BACKGROUND: Aim of this study is to investigate the changes in diabetes-related traits before and after DP and to clarify the incidence of diabetes and its predictors.

DETAILS: Among 493 registered patients, 117 underwent DP. Among these, 56 patients without diabetes before surgery were included in the study. Glucose and endocrine function were prospectively assessed using a 75-g oral glucose tolerance test preoperatively, 1 month after DP, and every 6 months thereafter for up to 36 months. Pancreatic volumetry was performed using multidetector row computed tomography before and after surgery. Insulin secretion decreased and blood glucose levels worsened after DP. Residual pancreatic volume was significantly associated with the reserve capacity of insulin secretion but not with blood glucose levels or the development of diabetes. Among 56 patients, 33 developed diabetes mellitus. The cumulative incidence of diabetes at 36 months after DP was 74.1%. Multivariate Cox regression analysis showed that impaired glucose tolerance as a preoperative factor as well as a decreased insulinogenic index and impaired glucose tolerance at 1 month postoperatively were identified as risk factors for diabetes following DP.

Copyright © The Author(s). Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved.

Source: Imamura, S., Niwano. F., Babaya, N., et al. (2024). High Incidence of Diabetes Mellitus After Distal Pancreatectomy and Its Predictors: A Long-term Follow-up Study. The Journal of Clinical Endocrinology & Metabolism. 2024; 109(3): 619-630. Published: March, 2024. DOI: 10.1210/clinem/dgad634.

[Posted 22/Jan/2024]

AUDIENCE: Nephrology, Internal Medicine

KEY FINDINGS: Biomarkers of tubular injury and inflammation were associated with kidney structural parameters in early type 1 diabetes and may be indicators of kidney disease risk.

BACKGROUND: Whether biomarkers of tubular injury and inflammation indicate subclinical structural kidney pathology early in type 1 diabetes remains unknown.

DETAILS: Authors investigated associations of biomarkers of tubular injury and inflammation with kidney structural features in 244 adults with type 1 diabetes from the Renin-Angiotensin System Study, a randomized, placebo-controlled trial testing effects of enalapril or losartan on changes in glomerular, tubulointerstitial, and vascular parameters from baseline to 5-year kidney biopsies. Biosamples at biopsy were assessed for kidney injury molecule 1 (KIM-1), soluble TNF receptor 1 (sTNFR1), arginine-to-citrulline ratio in plasma, and uromodulin and epidermal growth factor (EGF) in urine. We examined cross-sectional correlations between biomarkers and biopsy features and baseline biomarker associations with 5-year changes in biopsy features. Participants' mean age was 30 years (SD 10) and diabetes duration 11 years (SD 5); 53% were women. The mean GFR measured by iohexol disappearance was 128 ml/min per 1.73 m2 (SD 19) and median urinary albumin excretion was 5 μg/min (interquartile range, 3–8). KIM-1 was associated with most biopsy features: higher mesangial fractional volume (0.5% [95% confidence interval (CI), 0.1 to 0.9] greater per SD KIM-1), glomerular basement membrane (GBM) width (14.2 nm [95% CI, 6.5 to 22.0] thicker), cortical interstitial fractional volume (1.1% [95% CI, 0.6 to 1.6] greater), fractional volume of cortical atrophic tubules (0.6% [95% CI, 0.2 to 0.9] greater), and arteriolar hyalinosis index (0.03 [95% CI, 0.1 to 0.05] higher). sTNFR1 was associated with higher mesangial fractional volume (0.9% [95% CI, 0.5 to 1.3] greater) and GBM width (12.5 nm [95% CI, 4.5 to 20.5] thicker) and lower GBM surface density (0.003 μm2/μm3 [95% CI, 0.005 to 0.001] lesser). EGF and arginine-to-citrulline ratio correlated with severity of glomerular and tubulointerstitial features. Baseline sTNFR1, uromodulin, and EGF concentrations were associated with 5-year glomerular and tubulointerstitial feature progression.

Copyright © American Society of Nephrology. All rights reserved.

Source: Limonte, C., Prince, D., Hoofnagle, A. N., et al. (2023). Associations of Biomarkers of Tubular Injury and Inflammation with Biopsy Features in Type 1 Diabetes. Clinical Journal of the American Society of Nephrology. 2024; 19(1): 44-55, January 2024. Published: January, 2024. DOI: 10.2215/CJN.0000000000000333.

[Posted 18/Jan/2024]

AUDIENCE: Endocrinology, Ophthalmology

KEY FINDINGS: Teprotumumab significantly improved proptosis vs placebo in longstanding/low inflammation TED, demonstrating efficacy regardless of disease duration/activity. The safety profile was comparable to that previously reported.

BACKGROUND: Early inflammatory thyroid eye disease (TED) can lead to symptomatic chronic disease, including disabling proptosis. Teprotumumab, an insulin-like growth factor-1 receptor (IGF-1R) inhibitor, previously demonstrated efficacy in acute, high-inflammation TED trials. Objective of the study was to present data from the first placebo-controlled trial with teprotumumab in chronic/low disease activity TED.

DETAILS: This randomized double-masked, placebo-controlled trial, conducted at 11 US centers, enrolled adult participants with TED duration of 2 to 10 years, Clinical Activity Score (CAS) <= 1 or no additional inflammation or progression in proptosis/diplopia for >=1 year, proptosis >=3 mm from before TED and/or from normal, euthyroid/mildly hypo/hyperthyroid, no prior teprotumumab, and no steroids within 3 weeks of baseline. Patients received (2:1) intravenous teprotumumab or placebo once every 3 weeks (total 8 infusions). The primary endpoint was proptosis (mm) improvement at Week 24. Adverse events (AEs) were assessed. A total of 62 (42 teprotumumab and 20 placebo) patients were randomized. At Week 24, least squares mean (SE) proptosis improvement was greater with teprotumumab (-2.41 [0.228]) than with placebo (-0.92 [0.323]), difference -1.48 (95% CI -2.28, -0.69; P = .0004). Proportions of patients with AEs were similar between groups. Hyperglycemia was reported in 6 (15%) vs 2 (10%) and hearing impairment in 9 (22%) vs 2 (10%) with teprotumumab and placebo, respectively. AEs led to discontinuation in 1 teprotumumab (left ear conductive hearing loss with congenital anomaly) and 1 placebo patient (infusion-related). There were no deaths.

Copyright © The Author(s). Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved.

Source: Douglas, R. S., Couch, S., Wester, S. T., et al. (2024). Efficacy and Safety of Teprotumumab in Patients With Thyroid Eye Disease of Long Duration and Low Disease Activity. The Journal of Clinical Endocrinology & Metabolism. 2024; 109(1): 25-35. Published: January, 2024. DOI: 10.1210/clinem/dgad637.

Definition of Syndrome-Specific Reference Ranges.

[Posted 13/Nov/2023]

AUDIENCE: Endocrinology, Pediatric, Family Medicine

KEY FINDINGS: By longitudinally assessing TFT in a wide pediatric DS population, we outlined the syndrome-specific reference nomograms for TSH, FT3, and FT4 and demonstrated a persistent upward shift of TSH compared to non-syndromic children.

BACKGROUND: The lack of syndrome-specific reference ranges for thyroid function tests (TFT) among pediatric patients with Down syndrome (DS) results in an overestimation of the occurrence of hypothyroidism in this population. Aim of this study is to (a) outline the age-dependent distribution of TFT among pediatric patients with DS; (b) describe the intraindividual variability of TFT over time; and (c) assess the role of elevated thyrotropin (TSH) in predicting the future onset of overt hypothyroidism.

DETAILS: In this retrospective, monocentric, observational analysis, authors included 548 patients with DS (0-18 years) longitudinally assessed between 1992 and 2022. Exclusion criteria were abnormal thyroid anatomy, treatments affecting TFT, and positive thyroid autoantibodies. Authors determined the age-dependent distribution of TSH, FT3, and FT4 and outlined the relative nomograms for children with DS. Compared with non-syndromic patients, median TSH levels were statistically greater at any age (P < .001). Median FT3 and FT4 levels were statistically lower than controls (P < .001) only in specific age classes (0-11 for FT3, 11-18 years for FT4). TSH levels showed a remarkable fluctuation over time, with a poor (23%-53%) agreement between the TSH centile classes at 2 sequential assessments. Finally, the 75th centile was the threshold above which TSH values predicted future evolution into overt hypothyroidism with the best statistical accuracy, with a satisfactory negative predictive value (0.91), but poor positive predictive value (0.15).

Copyright © The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved.

Source: Cattoni, A., Molinari, S., Capitoli, G., et al. (2023). Thyroid Function Tests in Children and Adolescents With Trisomy 21: Definition of Syndrome-Specific Reference Ranges. JCEM. 2023; 108(11): 2779-2788. Published: November, 2023. DOI: 10.1210/clinem/dgad333.