Nikolaus Schreiber

Dr. Nikolaus Schreiber

Medical University of Graz - Intensive Care Unit
orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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Verified
Journal Article
Open access
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SASimon Aberger
Simon Aberger
NSNikolaus Schreiber
Nikolaus Schreiber
Stefan PilzStefan Pilz
Stefan Pilz
KEKathrin Eller
Kathrin Eller
Alexander R RosenkranzAlexander R Rosenkranz
Alexander R Rosenkranz
AKAlexander H Kirsch
Alexander H Kirsch
High-dose vitamin D supplementation is common in the general population, but unsupervised high-dose supplementation in vitamin D-replete individuals poses a risk of severe toxicity. Susceptibility to vitamin D toxicity shows a significant inter-individual variability that may in part be explained by genetic predispositions (i.e., CYP24A1 polymorphism). The classic manifestation of vitamin D toxicity is hypercalcemia, which may be refractory to conventional therapy. Its causes include the endogenous overaction of 1α-hydroxylase, monogenic alterations affecting vitamin D metabolizing enzymes and exogenous vitamin D intoxication. In this manuscript, we include a literature review of potential pharmacological interventions targeting calcitriol metabolism to treat vitamin D intoxication and present a case of severe, exogenous vitamin D intoxication responding to systemic corticosteroids after the failure of conventional therapy. Systemic glucocorticoids alleviate acute hypercalcemia by inhibiting enteric calcium absorption and increasing the degradation of vitamin D metabolites but may cause adverse effects. Inhibitors of 1α-hydroxylase (keto/fluconazole) and inducers of CYP3A4 (rifampicin) may be considered steroid-sparing alternatives for the treatment of vitamin D intoxication.

1 May 2026 in Journal of Medical Internet Research
Verified
Journal Article
Open access
SLSebastian Labenbacher
Sebastian Labenbacher
MNMaximilian Niederer
Maximilian Niederer
SHSascha Hammer
Sascha Hammer
MBMathias Bader
Mathias Bader
NSNikolaus Schreiber
Nikolaus Schreiber
Helmar Bornemann-CimentiHelmar Bornemann-Cimenti
Helmar Bornemann-Cimenti
Background: Generative artificial intelligence (GenAI) tools are increasingly used in scientific research to support literature searches, evidence synthesis, and manuscript preparation. While these systems promise substantial efficiency gains, concerns have emerged regarding their reliability, particularly their tendency to cite inaccurate, fabricated, or retracted literature. The unrecognized inclusion of retracted studies poses a serious risk to research integrity and evidence-based decision-making. Whether commonly used GenAI tools can reliably detect, exclude, or transparently communicate the retraction status of scientific publications remains unclear. Objective: This study aimed to evaluate the ability of freely available GenAI tools to correctly handle retracted scientific articles during literature searches. Primary and secondary outcomes focused on accuracy, reliability, and consistency in recognizing retracted literature. Methods: In this pragmatic trial, nine widely used free-access GenAI tools (ChatGPT 4, ChatGPT 5, Claude, Gemini, Perplexity, Microsoft Copilot, SciSpace, ScienceOS, and Consensus) were evaluated. Each tool was asked five predefined, standardized questions addressing topic overview, article identification, article summarization, and explicit assessment of retraction status. Overall, 15 retracted articles (the 10 most cited and 5 most recently retracted as of May 23, 2025) were selected from the Retraction Watch database. All questions were repeated twice to assess intratool consistency. Responses were independently rated as correct or incorrect by 2 researchers. Descriptive statistics summarized performance, and comparisons between general-purpose and research-focused AI tools were conducted using descriptive statistics. Interreviewer agreement was assessed using Cohen kappa coefficient. Results: None of the evaluated AI tools consistently handled retracted articles correctly. No model achieved perfect accuracy across all question sets. ChatGPT 5 performed best, defined by the primary outcome of achieving fully correct responses to all five predefined tasks (5/5) for the highest number of retracted articles, correctly answering all five questions for 8 of 15 articles (53.3%). Research-focused tools (SciSpace, ScienceOS, and Consensus) failed to produce a single fully correct response set. Retracted articles were frequently included in topic overviews without warning, with error rates exceeding 40% in several tools. When specifically asked about retraction status, most systems failed to provide correct or complete information. OpenEvidence only reported data for a subset of our retracted articles as it is only used in health care literature. It demonstrated strong performance in topic overviews but low accuracy in identifying retracted articles. Conclusions: Freely available GenAI tools are currently not able to detect, exclude, or appropriately flag retracted scientific literature. The widespread and confident reproduction of retracted studies represents a substantial threat to research integrity, particularly in medical and evidence-based fields. Until retraction-aware verification mechanisms are systematically integrated, independent source checking remains essential when using AI-assisted literature tools.

10 July 2024 in Medizinische Klinik - Intensivmedizin und Notfallmedizin
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Journal Article
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GHGerald Hackl
Gerald Hackl
NSNikolaus Schreiber
Nikolaus Schreiber
Zusammenfassung: In seltenen Fällen benötigen PatientInnen mit lebensbedrohlichen Intoxikationen ein extrakorporales Verfahren zur erweiterten Giftelimination. Die Extracorporeal Treatments in Poisoning (EXTRIP) Workgroup bietet konsens- und evidenzbasierte Empfehlungen mit laufender Aktualisierung bezüglich des Einsatzes von extrakorporalen Verfahren im Management von kritisch kranken, vergifteten PatientInnen. Die extrakorporale Clearance ist am höchsten bei niedermolekularen Substanzen mit niedrigem Verteilungsvolumen, niedriger Plasmaproteinbindung und hoher Wasserlöslichkeit. Um den Effekt der extrakorporalen Clearance zu maximieren, sollten Blut- und Dialysatfluss so hoch wie möglich sein und die Membran mit der größten Oberfläche verwendet werden. Meistens kommt aufgrund der höchsten Effektivität die intermittierende Hämodialyse zur Anwendung, wobei hämodynamisch kompromittierte PatientInnen von einem kontinuierlichen Verfahren profitieren können.

1 January 2022 in Therapeutic Advances in Musculoskeletal Disease
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Journal Article
Open access
NGNina Gasperi
Nina Gasperi
NSNikolaus Schreiber
Nikolaus Schreiber
PBPhilipp Bosch
Philipp Bosch
AAAntonella Adinolfi
Antonella Adinolfi
AKArnd Kleyer
Arnd Kleyer
CDChristian Dejaco
Christian Dejaco
Purpose: The aim of this article is to examine the extent of structural and inflammatory lesions by ultrasound in elderly subjects with hand osteoarthritis (HOA) fulfilling the ACR classification criteria (Group A), in subjects with painless enlarged finger joints (Group B), and in individuals without clinical abnormalities at hands (Group C). Methods: This study was nested within the population-based, prospective Bruneck study; 293 subjects of ⩾65 years of age were assessed. Clinical and ultrasound assessment was conducted at wrists and finger joints. Gray scale synovitis (GSS), Power Doppler (PD), osteophytes, and erosions were scored semiquantitatively (0–3). The Short Form Score for the Assessment and Quantification of Chronic Rheumatic Affections of the Hands (SF-SACRAH), the Health Assessment Questionnaire (HAQ), and the Functional Index for Hand Osteoarthritis (FIHOA) were retrieved. Results: Most subjects had ⩾1 ultrasound abnormality, of which osteophytes were the most prevalent finding in all groups (Group A: 100%, Group B: 99.4%, and Group C: 93.9%). GSS and PD-signals were more common in Group A than in Group B (94% versus 67% and 33% versus 13%, respectively). In Group C, GSS was observed in 39.4% of subjects. In subjects with HOA, the SF-SACRAH correlated with osteophyte scores (corrcoeff = 0.48), and the FIHOA correlated with the osteophyte (corrcoeff = 0.42) and PD scores (corrcoeff = 0.33). Conclusion: GSS and PD were more frequent in patients with symptomatic HOA than in cases with painless bony enlargements and subjects without clinical joint abnormalities. Functional restriction in HOA is associated with structural and inflammatory ultrasound changes.

15 December 2025 in Journal of Clinical Anesthesia
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Journal Article
Open access
MKMichael Kolland
Michael Kolland
SSSelina Sartori
Selina Sartori
CKChristoph Klivinyi
Christoph Klivinyi
MSMichael Schörghuber
Michael Schörghuber
JPJakob Pannold
Jakob Pannold
NSNikolaus Schreiber
Nikolaus Schreiber
Acute kidney injury (AKI) is a common complication after coronary artery bypass grafting (CABG), associated with adverse short- and long-term outcomes. Sodium-glucose cotransporter-2 inhibitors (SGLT2i) have been shown to reduce occurrence of AKI in several populations, yet their perioperative effects in patients undergoing CABG are unknown. We conducted a retrospective study at the Department of Cardiac Surgery, Medical University of Graz (2020-2024) to evaluate the impact of preoperative SGLT2i use on cardiac surgery-associated AKI in adults undergoing urgent or emergent isolated coronary artery bypass grafting in patients with an indication for SGLT2i therapy (type 2 diabetes mellitus, heart failure with reduced ejection fraction, or chronic kidney disease). Patients with preoperative dialysis, sepsis, reoperation, mechanical circulatory support or missing laboratory data were excluded. Exposure was defined as SGLT2i use within two weeks before surgery, and the primary outcome was cardiac surgery-associated AKI (CSA-AKI) according to KDIGO criteria. Secondary outcomes included kidney replacement therapy, ICU length of stay, 30-day mortality and postoperative diabetic ketoacidosis. Causal effects were estimated using entropy balancing. Results were reported as weighted risk differences, risk ratios, and adjusted mean differences, with time-to-event outcomes analyzed via weighted Cox models and Kaplan-Meier estimates. Among 484 patients, 135 were on SGLT2i. CSA-AKI occurred in 23.0 % of SGLT2i users vs. 28.1 % of non-users (risk ratio of 0.63 [95 % CI 0.44-0.91; p = 0.014]). The association was pronounced in patients with heart failure with reduced ejection fraction and those with high EuroSCORE II. No differences were observed in other secondary endpoints and no cases of postoperative diabetic ketoacidosis occurred. Preoperative SGLT2i use was associated with a significantly lower risk of CSA-AKI in patients undergoing urgent or emergent CABG. These findings need to be confirmed in prospective multicenter trials but underline the favorable safety profile of this medication.

29 September 2025 in Journal of Advanced Nursing
Verified
Journal Article
Open access
SLSebastian Labenbacher
Sebastian Labenbacher
SHSascha Hammer
Sascha Hammer
AMAngelika Moser
Angelika Moser
NSNikolaus Schreiber
Nikolaus Schreiber
Helmar Bornemann-CimentiHelmar Bornemann-Cimenti
Helmar Bornemann-Cimenti
Introduction: Although healthcare infrastructure has improved in recent years, the preoperative journey of patients is often accompanied by anxiety. Allowing patients to walk to the operating theatre is a simple, yet underexplored strategy that may enhance their sense of autonomy and reduce anxiety. As patient‐centred care gains importance, evaluating the effects of this approach on patient‐reported outcomes may be more relevant than widely assumed. Aim: In this scoping review, we aim to analyse the published literature on preoperative walking into the operating theatre and patient‐reported outcomes, such as anxiety and satisfaction. Design: This study was a scoping review that followed the Joanna Briggs Institute methodology and Preferred Reporting Items for Systematic Reviews and Meta‐Analyses, Scoping Review extension guidelines. Methods: Inclusion criteria were adult patients undergoing elective surgery and walking to the operating theatre. Data were extracted using a standardised form, and critical appraisal was performed by using ROBINS‐I V2.0, RoB2 and ROB‐E tools. Data Sources: Embase, MEDLINE, Cochrane databases (OVID) and CINAHL (EBSCOhost) were searched up to 31st January 2025. Results: Our search identified 958 articles, with seven trials included in the final analysis. The studies, published between 1994 and 2022, involved 3001 patients from North America, Asia and Europe. The interventions varied, but most patients reported improved satisfaction and reduced anxiety when walking to the operating theatre. No adverse events were reported, although patient preferences varied, with younger patients more likely to prefer walking. Conclusion: Walking to the theatre positively impacts patient satisfaction and autonomy. However, patient selection is key, as not all individuals are physically or mentally prepared for walking. Future research could explore unaccompanied walking and its effects on hospital resource utilisation. Preoperative walking is a beneficial intervention that enhances patient satisfaction and reduces anxiety, providing a feasible alternative to bed transport for many elective surgical patients. Patient or Public Contribution: No patient or public involvement.