PURPOSE:Data on the reliability of point-of-care (POC) tests for the rapid diagnosis of periprosthetic joint infections (PJI) using synovial fluid (SF) D-dimer (DD), interleukin 6 (IL-6) and procalcitonin (PCT) are limited. This study aimed to address this issue by evaluating the diagnostic accuracy of POC tests for SF DD, IL-6 and PCT in comparison to standard laboratory devices for diagnosing PJI. METHODS:A total of 273 patients who underwent 300 revision arthroplasties were included in this study. According to the European Bone and Joint Infection criteria, 123 were classified as infected, 145 as aseptic revisions and 32 as likely infected. SF DD, IL-6 and PCT levels were quantified using both POC and standard laboratory tests. The diagnostic accuracy was assessed using receiver operating characteristic curves and area under the curve (AUC). RESULTS:Among POC tests, IL-6 demonstrated the highest AUC 0.83 (95% confidence interval CI 0.77-0.89), followed by DD (0.66, 95% CI 0.59-0.72), while PCT performed poorly (AUC 0.26, 95% CI 0.20-0.33). Laboratory-based IL-6 test outperformed all other markers (AUC 0.94, 95% CI 0.90-0.97). When using both POC and standard laboratory methods, significant differences were noted for IL-6 and DD (p < 0.001). Combining the POC test results for IL-6 and DD showed better diagnostic performance than either alone (AUC 0.92). In patients with PJI, biomarker levels differed by pathogen virulence, except for POC IL-6 (p = 0.631), POC DD (p = 0.080) and laboratory DD (p = 0.053). CONCLUSIONS:POC tests for SF, particularly those for IL-6, support the rapid PJI diagnosis, and combining POC IL‑6 with DD further improves diagnostic accuracy. These findings suggest that POC IL-6, either independently or in conjunction with DD, could be useful in situations where rapid decisions are required. However, its inferior performance compared to that of laboratory assays highlights the need for further optimisation and validation. LEVEL OF EVIDENCE:Level II, development of diagnostic criteria in a consecutive series of patients and a universally applied 'gold' standard.

Background: Sodium glucose-linked transport 2 inhibitors (SGLT2-Is) are well known to exert beneficial effects in chronic heart failure (CHF) independent of left ventricular ejection fraction (LVEF). As inflammation plays a key role in cardiac diseases, data on the association of inflammatory biomarkers and ventricular arrhythmic (VA) burden in SGLT2-I-treated patients is lacking. Methods: This pre-defined subanalysis investigated changes in pre-specified inflammatory biomarkers from baseline to week 52 in response to 5 mg Ertugliflozin compared to placebo and their associations to the incidence of VA burden. Results: A total of 36 patients (18 versus 18) with available biobank samples were included in the analysis. At week 52, leukocyte and neutrophil counts, as well as high-sensitive C-reactive protein (hsCRP) and interleukin-6 (IL-6), were numerically higher in the Ertugliflozin group. In contrast, neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were lower in the Ertugliflozin group, although these differences did not reach statistical significance. Notably, lymphocyte counts were significantly higher in Ertugliflozin showing a mean difference of 19.0 ± 10.78% (p = 0.028). Further, a significantly higher incidence of VA burden was observed among Ertugliflozin-treated patients with elevated hsCRP levels (incidence rate ratio [IRR] 3.58; 95% Confidence interval [CI], 1.12-11.40, p = 0.031). Conclusions: In patients with CHF, Ertugliflozin treatment was associated with a higher incidence of VA burden in those with elevated hsCRP levels. This may suggest a potential higher risk for VA in SGLT2-I-treated patients in the setting of heightened inflammatory activity. However, this finding is based on a single interaction analysis in a small sample size, and the results should therefore be considered exploratory and hypothesis-generating, and must be interpreted cautiously.

Vitamin D has multiple functions in most organs and tissues of the human body. In addition to its canonical role in bone and mineral metabolism, vitamin D impacts cell growth and differentiation, immunity, glucose homeostasis, cognition, and endocrine pathways. Mounting evidence links vitamin D deficiency to a broad spectrum of diseases including cardiovascular disease (CVD). Considering that both vitamin D deficiency and CVD are highly prevalent conditions, it is important to understand the potential interplay between these two. Observational studies consistently demonstrate an inverse relationship between the inactive prohormone 25-hydroxyvitamin D (25[OH]D) in serum, which represents the body's vitamin D reservoir, and CVD risk. Specifically, lower serum 25-(OH)D levels are associated with a higher risk of CVD events and CVD mortality. Putative mechanisms that mediate the pathophysiologic effects of vitamin D deficiency comprise oxidative stress, systemic inflammation, activation of the renin-angiotensin-aldosterone system, endothelial dysfunction, hypertension, and myocardial fibrosis. However, vitamin D supplementation failed to demonstrate significant CVD-related benefits. Although existing randomized, placebo-controlled supplementation studies yielded neutral results, most of these studies did not specifically target CVD outcomes. Another limitation of previous randomized controlled studies is the application of fixed vitamin D dosing regimens, regardless of the actual serum 25-(OH)D level. Studies that escalate the vitamin D dose until serum 25-(OH)D reaches a prespecified target range are largely lacking. This article reviews the existing literature on the role of vitamin D deficiency in CVD incidence, progression, and mortality.

Objective: We investigated whether fasting 2- Hydroxybutyrate (2-HB) measured by a novel enzymatic assay (XpressGT®) can provide incremental discrimination of dysglycemia beyond routine fasting measures. Research Design and Methods: Associations of 2-HB with dysglycemia were assessed in the total BioPersMed cohort and in the prespecified subcohort with FPG <110 mg/dL and HbA1c <39 mmol/mol (5.7%). Results: Among 772 individuals 2-HB increased from normoglycemia (39.0 µmol/L) to prediabetes (51.9 µmol/L) and type 2 diabetes (57.0 µmol/L). In 534 individuals with normal FPG and HbA1c, 2-HB yielded a ROC-AUC of 0.79 for postprandial dysglycemia (2-hour glucose >140 mg/dL during OGTT). A sensitivity of 90% was achieved at 39 µmol/L, with a negative predictive value of 98.9. Each SD increase in 2-HB was independently associated with dysglycemia (OR 2.23, p <0.001). Conclusions: Enzymatic 2-HB measurement may serve as a screening biomarker to rule out postprandial dysglycemia in individuals with normal FPG and HbA1c.

Background The field of pathology has not yet fully realized the potential of artificial intelligence (AI) and digital pathology. Adoption must be driven by demonstrable utility, and successful implementation depends on interoperability and sustainability, which require established standards. We address the imminent challenges facing the field of AI in digital pathology, which currently suffers from a lack of coordinated and adopted standards. Methods We conducted several roundtable discussions with key opinion leaders from multiple sectors across the healthcare ecosystem. Based on how standards are used, we distinguish different areas of practice (relevance, endorsement, and utility) and emphasize the importance of standards. Results Our roundtable discussion centered on one key theme: successfully implementing AI in digital pathology depends on achieving a certain level of uniformity across practices. We derive an approach to describe the critical role of standards consisting of seven interdependent areas of practice: value recognition, existing standards, dependencies for AI, failures, management of standards, trends, and a roadmap for accelerated and sustainable adoption. The promise of standards and our approach can be understood as the interconnection of these areas. We address imminent challenges surrounding the field of digital pathology by providing an approach for interoperable, coordinated, and sustainable use of standards across diverse practice settings. Conclusion With the concepts and frameworks outlined in this article, we highlight the importance of standards in pathology and their crucial role in driving computational advances and enabling AI solutions to enhance patient care.

Trimethylamine N-oxide (TMAO) is a microbiome-based metabolite known to increase with age, cardiovascular and other diseases, with average concentrations mostly higher in males. It was recently found to be associated with neurodegenerative diseases. In this context we aimed to investigate associations between TMAO, cardiometabolic risk factors, cognitive function and brain atrophy in older individuals (67.81 ± 8.86 years of age) with normal neurological status. TMAO was measured by liquid-chromatography tandem mass spectrometry in serum samples from 487 individuals. All participants underwent cognitive testing capturing executive function, motor and memory abilities. In 180 of these individuals, brain MRI was performed to investigate vascular and neurodegenerative changes. In the total cohort higher TMAO concentrations were positively associated with advanced age (p=0.01), BMI (p<0.01), fasting blood sugar (p<0.01), HbA1c (p<0.01) and diabetes (p=0.02). In contrast, we observed negative associations with total cholesterol (p=0.01), LDL (p=0.04) and HDL cholesterol (p=0.04). No significant differences in TMAO concentrations were found between females and males. MRI revealed higher TMAO levels to be associated with lower total grey matter, frontal lobar and hippocampal volume (p=0.01). Summarized, TMAO is associated with higher age, cardiometabolic risk factors and brain atrophy, while there was no difference between the two sexes of this community-dwelling elderly cohort. These findings support that TMAO is mainly a marker of aging processes but also associated with neurodegeneration, even though associations with cognitive functioning were not observed.

The International Osteoporosis Foundation (IOF) and the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) have proposed procollagen type I N propeptide (PINP) and β isomerized C-terminal telopeptide of type I collagen (β-CTX-I) as reference bone turnover markers (BTMs) for osteoporosis. This report examines the published literature since the 2011 IOF-IFCC position paper in order to determine the clinical potential of the reference BTMs and newer markers for the prediction of fracture risk and monitoring the treatment of osteoporosis. Evidence for the relationship between BTMs and subsequent fractures was gathered from prospective studies through literature review of the Medline database from years 2011 to May 2024. The impact of treatment on BTMs was also studied by examining publications in that period. Studies of the accuracy of BTMs in the assessment of bone turnover in the setting of advanced chronic kidney disease were also examined. Increased BTM concentrations are associated with higher fracture risk in postmenopausal women. PINP and β-CTX-I measured in blood are associated with fracture risk but their interaction with other risk factors has not been sufficiently studied limiting their incorporation into fracture risk algorithms. Treatment-induced changes in PINP and β-CTX-I account for a substantial proportion of fracture risk reduction and are useful for improving adherence; they are recommended for inclusion in studies to examine adherence in individual patients. However, total PINP (tPINP) and β-CTX-I may be elevated in CKD due to renal retention. Bone alkaline phosphatase (BALP), intact PINP (iPINP), and tartrate resistant acid phosphatase 5b (TRACP5b) show the most promise in discriminating high and low turnover bone diseases in patients with advanced CKD and for predicting fracture risk, monitoring treatment response, and assessing the risk of treatment-related complications. We re-affirm the use of serum/plasma tPINP and plasma β-CTX-I as reference BTMs with appropriate patient preparation and sample handling and measurement by standardized/harmonized assays in clinical studies to accumulate further data, and for monitoring treatment of osteoporosis in the setting of normal renal function in clinical practice. BALP and TRACP5b, measured by standardized assays, are recommended as reference BTMs for CKD-associated osteoporosis and should be included in observational and intervention studies to ascertain their utility for risk-evaluation, treatment initiation, and assessment of treatment response in CKD-associated osteoporosis.

OBJECTIVES:Accurate 25-hydroxyvitamin D (25-(OH)D) assays are essential for defining vitamin D status and ensuring appropriate clinical decisions. Standardization efforts, including the Vitamin D Standardization Program (VDSP), aim to minimize assay variability. This study evaluates the measurement uncertainty (MU) of various 25-(OH)D assays and their ability to detect physiologically relevant changes over time. METHODS:Seventeen pooled and eight single-donor serum samples were analyzed using two LC-MS/MS methods and 13 immunoassays, each applied in two independent laboratories. Imprecision, bias, and MU were assessed relative to the University of Ghent's reference measurement procedure (RMP). Results were compared against analytical performance specifications (APS) from VDSP, JCTLM-TF-RMSI, and IFCC C-BM based on physiological 25-(OH)D variation. A graphical approach was introduced to visualize MU in relation to clinical relevance. RESULTS:LC-MS/MS methods consistently met all APS criteria. Several immunoassays also achieved acceptable MU, although significant bias or inter-laboratory variability was observed for some of them. Slightly more than half of the assays met the desirable Joint Committee for Traceability in Laboratory Medicine Task Force on Reference Measurement System Implementation (JCTLM TF-RMSI) MU threshold (≤10 %), while four exceeded the minimum acceptable limit (≤15 %). The IFCC C-BM physiological approach identified a similar subset of assays. The graphical representation effectively illustrated method reliability across the tested concentration range. CONCLUSIONS:Measurement uncertainty remains a major challenge for 25-(OH)D assays. The integration of MU-based APS and graphical visualization provides a comprehensive framework for evaluating assay performance. These findings highlight the importance of selecting assays capable of reliably detecting clinically meaningful changes in vitamin D status.

Carbohydrate antigen 125 (CA125) is increasingly recognized as a biomarker in heart failure (HF). However, its response to sodium-glucose co-transporter 2 inhibitors (SGLT2i) after acute myocardial infarction (AMI) remains insufficiently explored. In this study, CA125 levels were measured from plasma samples collected in the EMMY trial, and robust linear mixed-effects models (R-LMEMs) were applied to assess the effects of empagliflozin on CA125 levels, their changes over a 26-week period, and their associations with established HF biomarkers. Our analysis showed that empagliflozin had no statistically significant effect on log-transformed CA125 levels. CA125 exhibited minor fluctuations at 6 weeks before declining at 26 weeks to a level below baseline, which had been measured shortly after AMI. Log-transformed CA125 was significantly associated with log-transformed N-terminal pro-B-type natriuretic peptide (NT-proBNP) and multiple echocardiographic parameters, including left ventricular ejection fraction (LVEF), end-diastolic and end-systolic dimensions, and volumes (LVEDD, LVEDV, LVESD, LVESV), and the ratio of early diastolic transmitral inflow velocity to early diastolic mitral annular velocity (E/e′). Notably, CA125’s associations with NT-proBNP and E/e′ were modified by empagliflozin. In conclusion, although CA125 showed significant associations with established HF biomarkers, it did not exhibit a parallel response to empagliflozin after AMI.

Human reproduction is intricately linked to systemic metabolic regulation, with disturbances in glucose metabolism adversely affecting fertility outcomes. Beyond their classical role in lipid digestion, bile acids (BAs), cholesterol-derived catabolites, have emerged as bioactive signaling molecules influencing glucose homeostasis and reproductive physiology. Notably, enhanced glycemic control observed after bariatric surgery, BA administration, or BA sequestrant therapy underscores the potential of BAs as regulators of glucose metabolism and as promising biomarkers or therapeutic targets in metabolic disorders. However, most existing studies investigating the endocrine function of BAs within the follicular environment have been limited to animal models, and the relationship between female metabolic status and the intrafollicular BA milieu in humans remains poorly understood. This study investigates whether systemic metabolic states modulate intrafollicular BA composition and examines how these changes may impact reproductive potential and in vitro fertilization outcomes. Comparative analysis of matched serum and follicular fluid (FF) samples revealed that the primary glycine-conjugated BA, glycochenodeoxycholic acid, was significantly elevated in FF, while the secondary BAs, deoxycholic acid and ursodeoxycholic acid, exhibited marked decreases in FF compared to serum (p < 0.001). K-means clustering of intrafollicular BA concentrations identified two distinct groups characterized by significantly different BA levels in both FF and serum (p ≤ 0.0001 and p < 0.05, respectively). Among the glucometabolic parameters assessed, glucose emerged as a critical determinant of cluster separation, exhibiting the strongest positive correlation with PC1 (r = 0.43, p < 0.01). A linear regression model further substantiated that intrafollicular BA concentrations were dependent on fasting plasma glucose levels (p ≤ 0.01). Elevated plasma glucose also correlated significantly with markers of insulin resistance and metabolic syndrome risk, including HOMA-IR (r = 0.39, p = 0.01), triglyceride/HDL cholesterol ratio (r = 0.33, p = 0.04) and leptin/adiponectin ratio (r = 0.37, p = 0.02). Interestingly, women with higher intrafollicular BA levels showed fewer follicles, zygotes, and blastocysts but experienced higher clinical pregnancy rates following frozen embryo transfer (p < 0.05). These findings reveal a novel link between systemic glucose metabolism and intrafollicular BA homeostasis, suggesting that subtle metabolic imbalances may impair oocyte maturation and embryo development, while potentially enhancing endometrial receptivity or embryo competence in frozen cycles.

Vitamin D deficiency is common in patients with chronic kidney disease (CKD) and associates with poor outcomes. Current clinical practice guidelines recommend supplementation with nutritional vitamin D as for the general population. However, recent large-scale clinical trials in the general population failed to demonstrate a benefit of vitamin D supplementation on skeletal or non-skeletal outcomes, fueling a debate on the rationale for screening for and correcting vitamin D deficiency, both in non-CKD and CKD populations. In a collaboration between the European Renal Osteodystrophy initiative of the European Renal Association (ERA) and the European Society for Paediatric Nephrology (ESPN), an expert panel performed an extensive literature review and formulated clinical practice points on vitamin D supplementation in children and adults with CKD and after kidney transplantation. These were reviewed by a Delphi panel of members from relevant working groups of the ERA and ESPN. Key clinical practice points include recommendations to monitor for, and correct, vitamin D deficiency in children and adults with CKD and after kidney transplantation, targeting 25-hydroxyvitamin D levels >75 nmol/l (>30 ng/ml). Although vitamin D supplementation appears well-tolerated and safe, it is recommended to avoid mega-doses (≥100 000 IU) and very high levels of 25 hydroxyvitamin D (>150-200 nmol/l, or 60-80 ng/ml) to reduce the risk of toxicity. Future clinical trials should investigate the benefit of vitamin D supplementation on patient-relevant outcomes in the setting of vitamin D deficiency across different stages of CKD.

Vitamin D deficiency is common in patients with chronic kidney disease (CKD) and associates with poor outcomes. Current clinical practice guidelines recommend supplementation with nutritional vitamin D as for the general population. However, recent large-scale clinical trials in the general population failed to demonstrate a benefit of vitamin D supplementation on skeletal or non-skeletal outcomes, fueling a debate on the rationale for screening for and correcting vitamin D deficiency, both in non-CKD and CKD populations. In a collaboration between the European Renal Osteodystrophy initiative of the European Renal Association (ERA) and the European Society for Paediatric Nephrology (ESPN), an expert panel performed an extensive literature review and formulated clinical practice points on vitamin D supplementation in children and adults with CKD and after kidney transplantation. These were reviewed by a Delphi panel of members from relevant working groups of the ERA and ESPN. Key clinical practice points include recommendations to monitor for, and correct, vitamin D deficiency in children and adults with CKD and after kidney transplantation, targeting 25-hydroxyvitamin D levels >75 nmol/l (>30 ng/ml). Although vitamin D supplementation appears well-tolerated and safe, it is recommended to avoid mega-doses (≥100 000 IU) and very high levels of 25 hydroxyvitamin D (>150–200 nmol/l, or 60–80 ng/ml) to reduce the risk of toxicity. Future clinical trials should investigate the benefit of vitamin D supplementation on patient-relevant outcomes in the setting of vitamin D deficiency across different stages of CKD.

Osteoporosis and sarcopenia are both common age-related disorders that are associated with increased morbidity and mortality. Bone and muscle are metabolically very active tissues that require large amounts of energy. Bile acids (BAs), a group of liver-derived steroid compounds, are primarily known as emulsifiers that facilitate the resorption of dietary fat and lipids. In addition, they have pleiotropic metabolic functions in lipoprotein and glucose metabolism, inflammation, and intestinal bacterial growth. Through these effects, they are related to metabolic diseases, such as diabetes, hypertriglyceridemia, atherosclerosis, and nonalcoholic steatohepatitis. BAs mediate their metabolic effects through receptor dependent and receptor-independent mechanisms. Emerging evidence suggests that BAs are also involved in bone and muscle metabolism. Under normal circumstances, BAs support bone health by shifting the delicate equilibrium of bone turnover toward bone formation. In contrast, low or excessive amounts of BAs promote bone resorption. In cholestatic liver disease, BAs accumulate in the liver, reach toxic concentrations in the circulation, and thus may contribute to bone loss and muscle wasting. In addition, the measurement of BAs is in rapid evolution with modern mass spectrometry techniques that allow for the detection of a continuously growing number of BAs. This review provides a comprehensive overview of the biochemistry, physiology and measurement of bile acids. Furthermore, it summarizes the existing literature regarding their role in bone and muscle.