DEBATE-statistical analysis plans for observational studies

Calcium supplementation during trauma resuscitation: a propensity score-matched analysis from the TraumaRegister DGU®

BACKGROUND

In major trauma patients, hypocalcemia is associated with increased mortality. Despite the absence of strong evidence on causality, early calcium supplementation has been recommended. This study investigates whether calcium supplementation during trauma resuscitation provides a survival benefit.

METHODS

We conducted a retrospective analysis using data from the TraumaRegister DGU® (2015-2019), applying propensity score matching to balance demographics, injury severity, and management between major trauma patients with and without calcium supplementation. 6 h mortality, 24 h mortality, and in-hospital mortality were considered as primary outcome parameters.

RESULTS

Within a cohort of 28,323 directly admitted adult major trauma patients at a European trauma center, 1593 (5.6%) received calcium supplementation. Using multivariable logistic regression to generate propensity scores, two comparable groups of 1447 patients could be matched. No significant difference in early mortality (6 h and 24 h) was observed, while in-hospital mortality appeared higher in those with calcium supplementation (28.3% vs. 24.5%, P = 0.020), although this was not significant when adjusted for predicted mortality (P = 0.244).

CONCLUSION

In this matched cohort, no evidence was found for or against a survival benefit from calcium supplementation during trauma resuscitation. Further research should focus on understanding the dynamics and kinetics of ionized calcium levels in major trauma patients and identify if specific conditions or subgroups could benefit from calcium supplementation.

Patient-reported outcomes at three months after pancreatic surgery for benign and malignant diseases - A prospective observational study

BACKGROUND/OBJECTIVES

Pancreatic surgery may have a long-lasting effect on patients' health status and quality of life (QoL). We aim to evaluate patient-reported outcomes (PRO) 3 months after pancreatic surgery.

METHODS

Patients scheduled for pancreatic surgery were enrolled in a prospective trial at five German centers. Patients completed PRO questionnaires (EQ-5D-5L, EORTC QLQ-PAN26, patient-reported happiness, and HADS-D), we report the first follow-up 3 months after surgery as an interim analysis. Statistical testing was performed using R software.

RESULTS

From 2019 to 2022 203 patients were enrolled, a three-month follow-up questionnaire was available in 135 (65.5 %). 77 (57.9 %) underwent surgery for malignant disease. Patient-reported health status (EQ-5D-5L) was impaired in 4/5 dimensions (mobility, self-care, usual activities, pain, discomfort) for patients with malignant and 3/5 dimensions (mobility, self-care, usual activities) for patients with benign disease 3 months after surgery (p < 0.05). Patients with malignant disease reported an increase in depressive symptoms, patients with benign disease had a decrease in anxiety symptoms (HADS-D; depression: 5.00 vs 6.51, p = 0.002; anxiety: 8.04 vs. 6.34, p = 0.030). Regarding pancreatic-disease-specific symptoms (EORTC-QLQ-PAN26), patients with malignant disease reported increased problems with taste, weight loss, weakness in arms and legs, dry mouth, body image and troubling side effects at three months. Patients with benign disease indicated more weakness in arms and legs, troubling side effects but less future worries at three months.

CONCLUSION

Patient-reported outcomes of patients undergoing pancreatic surgery for benign vs. malignant disease show important differences. Patients with malignant tumors report more severely decreased quality of life 3 months postoperatively than patients with benign tumors.

Effects of a single cash transfer on school re-enrollment during COVID-19 among vulnerable adolescent girls in Kenya: Randomized controlled trial

COVID-19 related school closures in Kenya were among the longest in Africa, putting older adolescent girls nearing the end of secondary school at risk of permanent dropout. Using a randomized-controlled trial we evaluated a logistically simple cash transfer intervention in urban areas designed to promote their return to school. There were no required conditions for receiving the transfer and the intervention is interpreted as a labeled cash transfer. It had substantial significant effects on re-enrollment of adolescent girls, with greater effectiveness for older girls and even for some not enrolled earlier in the school year. The program effectiveness demonstrates feasibility of the approach and underscores the potential importance of additional resources for schooling during the pandemic, when a large majority of households had suffered income losses.

Infants' immunisations, their timing and the risk of allergic diseases (INITIAL): an observational prospective cohort study protocol

INTRODUCTION

Vaccinations are considered to have a large impact on disease control, hence a multitude of vaccines in infancy is recommended. Retrospective studies suggest a possible relation between timing, kind or number of vaccines given in the first year of life and the subsequent incidence of allergic diseases. It must be clarified whether a causal relationship exists to ensure safety and reduce vaccine hesitancy.

METHODS AND ANALYSIS

Due to the high recommendation rate of vaccines, a long-term randomised controlled trial is not considered as ethically acceptable. Therefore, this study aims to observe prospectively the allergic incidence at the age of 5 years after various vaccine interventions in the early months of life.Parents of infants up to the age of 4-6 weeks will be recruited before the first recommended vaccination. Relevant prognostic factors for allergies, status of immunisation and general health will be evaluated up to the age of 5.Allergic symptoms will be assessed by the International Study of Asthma and Allergies in Childhood-questionnaire and a medical confirmation of the allergy is mandatory.The main objective is to compare the incidence of asthma, atopic dermatitis, rhinoconjunctivitis, food allergy or any of these atopies at the age of 5 between infants who were not vaccinated or were vaccinated according to recommendations in the first year of life.The sample size calculation with about 4000 participants can prove a 5% difference to the basic prevalence with about 80% power and global 5% alpha error for the five primary endpoints adjusting according to Bonferroni-Holm and assuming a rate of 10% not early vaccinated infants.

ETHICS AND DISSEMINATION

The study was registered (DRKS00029677) and has received approval by the ethics committee of Universität Witten/Herdecke (no. 113/2022). The results will be published.

Toward Open and Reproducible Epidemiology

Starting in the 2010s, researchers in the experimental social sciences rapidly began to adopt increasingly open and reproducible scientific practices. These practices include publicly sharing deidentified data when possible, sharing analytical code, and preregistering study protocols. Empirical evidence from the social sciences suggests such practices are feasible, can improve analytical reproducibility, and can reduce selective reporting. In academic epidemiology, adoption of open-science practices has been slower than in the social sciences (with some notable exceptions, such as registering clinical trials). Epidemiologic studies are often large, complex, conceived after data have already been collected, and difficult to replicate directly by collecting new data. These characteristics make it especially important to ensure their integrity and analytical reproducibility. Open-science practices can also pay immediate dividends to researchers' own work by clarifying scientific reasoning and encouraging well-documented, organized workflows. We consider how established epidemiologists and early-career researchers alike can help midwife a culture of open science in epidemiology through their research practices, mentorship, and editorial activities.

Interactions in the 2×2×2 factorial randomised clinical STEPCARE trial and the potential effects on conclusions: a protocol for a simulation study

Background

Randomised clinical trials with a factorial design may assess the effects of multiple interventions in the same population. Factorial trials are carried out under the assumption that the trial interventions have no interactions on outcomes. Here, we present a protocol for a simulation study investigating the consequences of different levels of interactions between the trial interventions on outcomes for the future 2×2×2 factorial designed randomised clinical Sedation, TEmperature, and Pressure after Cardiac Arrest and REsuscitation (STEPCARE) trial in comatose patients after out-of-hospital cardiac arrest.

Methods

By simulating a multisite trial with 50 sites and 3278 participants, and a presumed six-month all-cause mortality of 60% in the control population, we will investigate the validity of the trial results with different levels of interaction effects on the outcome. The primary simulation outcome of the study is the risks of type-1 and type-2 errors in the simulated scenarios, i.e. at what level of interaction is the desired alpha and beta level exceeded. When keeping the overall risk of type-1 errors ≤ 5% and the risk of type-2 errors ≤ 10%, we will quantify the maximum interaction effect we can accept if the planned sample size is increased by 5% to take into account possible interaction between the trial interventions. Secondly, we will assess how interaction effects influence the minimal detectable difference we may confirm or reject to take into account 5% (small interaction effect), 10% (moderate), or 15% (large) positive interactions in simulations with no ‘true’ intervention effect (type-1 errors) and small (5%), moderate (10%), or large negative interactions (15%) in simulations with ‘true’ intervention effects (type-2 errors). Moreover, we will investigate how much the sample size must be increased to account for a small, moderate, or large interaction effects.

Discussion

This protocol for a simulation study will inform the design of a 2×2×2 factorial randomised clinical trial of how potential interactions between the assessed interventions might affect conclusions. Protocolising this simulation study is important to ensure valid and unbiased results.

Trial registration

Not relevant

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06796-7.

The first 20 months of the COVID-19 pandemic: Mortality, intubation and ICU rates among 104,590 patients hospitalized at 21 United States health systems

Main objective

There is limited information on how patient outcomes have changed during the COVID-19 pandemic. This study characterizes changes in mortality, intubation, and ICU admission rates during the first 20 months of the pandemic.

Study design and methods

University of Wisconsin researchers collected and harmonized electronic health record data from 1.1 million COVID-19 patients across 21 United States health systems from February 2020 through September 2021. The analysis comprised data from 104,590 adult hospitalized COVID-19 patients. Inclusion criteria for the analysis were: (1) age 18 years or older; (2) COVID-19 ICD-10 diagnosis during hospitalization and/or a positive COVID-19 PCR test in a 14-day window (+/- 7 days of hospital admission); and (3) health system contact prior to COVID-19 hospitalization. Outcomes assessed were: (1) mortality (primary), (2) endotracheal intubation, and (3) ICU admission.

Results and significance

The 104,590 hospitalized participants had a mean age of 61.7 years and were 50.4% female, 24% Black, and 56.8% White. Overall risk-standardized mortality (adjusted for age, sex, race, ethnicity, body mass index, insurance status and medical comorbidities) declined from 16% of hospitalized COVID-19 patients (95% CI: 16% to 17%) early in the pandemic (February-April 2020) to 9% (CI: 9% to 10%) later (July-September 2021). Among subpopulations, males (vs. females), those on Medicare (vs. those on commercial insurance), the severely obese (vs. normal weight), and those aged 60 and older (vs. younger individuals) had especially high mortality rates both early and late in the pandemic. ICU admission and intubation rates also declined across these 20 months.

Conclusions

Mortality, intubation, and ICU admission rates improved markedly over the first 20 months of the pandemic among adult hospitalized COVID-19 patients although gains varied by subpopulation. These data provide important information on the course of COVID-19 and identify hospitalized patient groups at heightened risk for negative outcomes.

Trial registration

ClinicalTrials.gov Identifier: NCT04506528 (https://clinicaltrials.gov/ct2/show/NCT04506528).

Study protocol: assessing the association between corporate financial influence and implementation of policies to tackle commercial determinants of non-communicable diseases: a cross-sectional analysis of 172 countries

INTRODUCTION

There are many case studies of corporations that have worked to undermine health policy implementation. It is unclear whether countries that are more exposed to corporate financial influence are systematically less likely to implement robust health policies that target firms' financial interests. We aim to assess the association between corporate financial influence and implementation of WHO-recommended policies to constrain sales, marketing and consumption of tobacco, alcohol and unhealthy foods.

METHODS AND ANALYSIS

We will perform a cross-sectional analysis of 172 WHO Member States using national datasets from 2015, 2017 and 2020. We will use random effects generalised least squares regression to test the association between implementation status of 12 WHO-recommended tobacco, alcohol and diet policies, and corporate financial influence, a metric that combines disclosure of campaign donations, public campaign finance, corporate campaign donations, legislature corrupt activities, disclosure by politicians and executive oversight. We will control for GDP per capita, population aged >65 years (%), urbanisation (%), level of democracy, continent, ethno-linguistic fractionalisation, legal origin, UN-defined 'Small Island Developing States' and Muslim population (%) (to capture alcohol policy differences). We will include year dummies to address the possibility of a spurious relationship between the outcome variable and the independent variables of interests. For example, there may be an upward global trend in policy implementation that coincides with an upward global trend in the regulation of lobbying and campaign finance.

ETHICS AND DISSEMINATION

As this study uses publicly available data, ethics approval is not required. The authors have no conflicts of interest to declare. Findings will be submitted to a peer-reviewed journal for publication in the academic literature. All data, code and syntax will be made publicly available on GitHub.

Challenges and recommendations for high quality research using electronic health records

Harnessing Real World Data is vital to improve health care in the 21st Century. Data from Electronic Health Records (EHRs) are a rich source of patient centred data, including information on the patient's clinical condition, laboratory results, diagnoses and treatments. They thus reflect the true state of health systems. However, access and utilisation of EHR data for research presents specific challenges. We assert that using data from EHRs effectively is dependent on synergy between researchers, clinicians and health informaticians, and only this will allow state of the art methods to be used to answer urgent and vital questions for patient care. We propose that there needs to be a paradigm shift in the way this research is conducted - appreciating that the research process is iterative rather than linear. We also make specific recommendations for organisations, based on our experience of developing and using EHR data in trusted research environments.

The Role of Registries in Kidney Transplantation Across International Boundaries

Transplant professionals strive to improve domestic kidney transplantation rates safely, cost efficiently, and ethically, but to increase rates further may wish to allow their recipients and donors to traverse international boundaries. Travel for transplantation presents significant challenges to the practice of transplantation medicine and donor medicine, but can be enhanced if sustainable international registries develop to include low- and low-middle income countries. Robust data collection and sharing across registries, linking pretransplant information to post-transplant information, linking donor to recipient information, increasing living donor transplant activity through paired exchange, and ongoing reporting of results to permit flexibility and adaptability to changing clinical environments, will all serve to enhance kidney transplantation across international boundaries.

Observational Studies: Specific Considerations for the Physical and Rehabilitation Medicine Physician

ABSTRACT

The development of high-quality research is desired in all healthcare fields. Experimental and nonexperimental designs are used to investigate the effect or association of an intervention and clinical or surrogate outcome. The aims of these methods are to improve knowledge and to develop new strategies to manage a disease or condition. Randomized clinical trials are considered one of the standard methods to test the efficacy of a new drug or intervention; however, they are costly, have reduced generalizability, and cannot be feasible in all scenarios. Well-designed observational studies can provide valuable information regarding exposure factor and the event under investigation. In physical and rehabilitation medicine, where complex procedures and multiple risk factors can be involved in the same disease, the use of observational study must be planned in detail and a priori to avoid overestimations. In this article, we will give an overview of the methods used for observational design studies in physical and rehabilitation medicine using clinical examples to illustrate each method. We will describe when it is appropriate and how to use the observational studies in different scenarios explaining how to deal with potential bias and confounders using the adequate design and statistical plan for the situation.

Association Between Consumption of Fermented Food and Food-Derived Prebiotics With Cognitive Performance, Depressive, and Anxiety Symptoms in Psychiatrically Healthy Medical Students Under Psychological Stress: A Prospective Cohort Study

Background

Gut microbiota-based therapeutic strategies, such as probiotic and prebiotic preparations, may benefit mental health. However, commonly consumed fermented and prebiotic-containing foods have not been well-tested. The aim of the present study was to determine whether consumption of fermented food and food-derived prebiotics is associated with cognitive performance, depressive, and anxiety symptoms in psychiatrically healthy medical students under psychological stress.

Methods

The study protocol with data analysis plan was prospectively registered. Food consumption was evaluated with a 7-day dietary record. Cognitive performance was modeled with academic examination performance in relation to subject knowledge. Pre-exam depressive and anxiety symptoms were assessed with the Patient Health Questionnaire-9 and Generalized Anxiety Disorder-7, respectively.

Results

In total, 372 medical students (22.7 ± 1.1 years of age, 66% female) completed the study. No relationship was observed between cognitive performance under stress and either fermented food (adjusted β 0.02, 95% CI −0.07–0.11, p = 0.63) or food-derived prebiotics consumption (adjusted β −0.00, 95% CI −0.09–0.09, p = 0.99). High intake of fermented food was associated with more severe depressive (adjusted β 0.11, 95% CI 0.01–0.20, p = 0.032) and anxiety symptoms under stress (adjusted β 0.13, 95% CI 0.04–0.22, p = 0.0065); however, no such link was observed for food-derived prebiotics (adjusted β 0.03, 95% CI −0.07–0.13, p = 0.50 and −0.01, 95% CI −0.11–0.08, p = 0.83, for depression and anxiety, respectively).

Conclusions

Under psychological stress in medical students, consumption of fermented food and food-derived prebiotics appears to be not associated with cognitive performance. High intake of fermented food, but not food-derived prebiotics, may be associated with severity of depressive and anxiety symptoms. The safety of fermented food in this regard therefore requires further clarification.

A Cross-Sectional Study on Canine and Feline Anal Sac Disease

Simple Summary

Anal sac disease is a common problem in private practice, but there is surprisingly little information available about anal sac disease in the literature. In this article, the incidence, predisposing factors, diagnostics, treatment options, and recurrence rates were investigated by the use of a questionnaire which was distributed among veterinarians in private practice. Dogs were more commonly affected than cats. Diarrhea and skin problems increased the risk for anal sac disease, and certain breeds were more often affected. Diagnosis was made based on the presence of clinical signs and characteristics of the anal sac content. Manual expression and treating any potential underlying disease were the most important treatments. Surgical removal was performed in the case of frequent recurrence. Surgical outcome of anal sacculectomy can be improved when surgery is performed after medical management. Future studies should investigate if these findings reported by veterinarians can be confirmed by asking veterinarians to keep a logbook on dogs and cats with anal sac disease.

Abstract

Limited data are available on canine and feline non-neoplastic anal sac disease. Therefore, the aim of this study was to obtain observational data on the incidence, predisposing factors, diagnosis, treatment, and recurrence rate of canine and feline anal sac disease. To this end, a questionnaire was distributed among veterinarians. The incidence of non-neoplastic anal sac disease was estimated at 15.7% in dogs and 0.4% in cats. Predisposing factors were diarrhea, skin problems, several dog breeds, and particularly small breed dogs, male cats, British shorthairs, and obesity in dogs. Diagnosis was made based on the presence of clinical signs and characteristics of the anal sac content. Manual expression and treating any potential underlying disease were the most important treatments for all three types of non-neoplastic anal sac disease. Anal sacculectomy was performed in refractory cases. The most recurrent anal sac disease condition was impaction. Diagnosis of anal sac disease should be based on clinical signs and rectal examination, as the evaluation of the anal sac content is not reliable. Surgical outcomes of anal sacculectomy can be improved when surgery is performed after medical management. Future studies should investigate these findings in prospective trials.

National and international kidney failure registries: characteristics, commonalities, and contrasts

Registries are essential for health infrastructure planning, benchmarking, continuous quality improvement, hypothesis generation, and real-world trials. To date, data from these registries have predominantly been analyzed in isolated "silos," hampering efforts to analyze "big data" at the international level, an approach that provides wide-ranging benefits, including enhanced statistical power, an ability to conduct international comparisons, and greater capacity to study rare diseases. This review serves as a valuable resource to clinicians, researchers, and policymakers, by comprehensively describing kidney failure registries active in 2021, before proposing approaches for inter-registry research under current conditions, as well as solutions to enhance global capacity for data collaboration. We identified 79 kidney-failure registries spanning 77 countries worldwide. International Society of Nephrology exemplar initiatives, including the Global Kidney Health Atlas and Sharing Expertise to support the set-up of Renal Registries (SharE-RR), continue to raise awareness regarding international healthcare disparities and support the development of universal kidney-disease registries. Current barriers to inter-registry collaboration include underrepresentation of lower-income countries, poor syntactic and semantic interoperability, absence of clear consensus guidelines for healthcare data sharing, and limited researcher incentives. This review represents a call to action for international stakeholders to enact systemic change that will harmonize the current fragmented approaches to kidney-failure registry data collection and research.

How to Develop Statistical Predictive Risk Models in Oncology Nursing to Enhance Psychosocial and Supportive Care

OBJECTIVES

Predictive risk models are advocated in psychosocial oncology practice to provide timely and appropriate support to those likely to experience the emotional and psychological consequences of cancer and its treatments. New digital technologies mean that large scale and routine data collection are becoming part of everyday clinical practice. Using these data to try to identify those at greatest risk for late psychosocial effects of cancer is an attractive proposition in a climate of unmet need and limited resource. In this paper, we present a framework to support the development of high-quality predictive risk models in psychosocial and supportive oncology. The aim is to provide awareness and increase accessibility of best practice literature to support researchers in psychosocial and supportive care to undertake a structured evidence-based approach.

DATA SOURCES

Statistical prediction risk model publications.

CONCLUSION

In statistical modeling and data science different approaches are needed if the goal is to predict rather than explain. The deployment of a poorly developed and tested predictive risk model has the potential to do great harm. Recommendations for best practice to develop predictive risk models have been developed but there appears to be little application within psychosocial and supportive oncology care.

IMPLICATIONS FOR NURSING PRACTICE

Use of best practice evidence will ensure the development and validation of predictive models that are robust as these are currently lacking. These models have the potential to enhance supportive oncology care through harnessing routine digital collection of patient-reported outcomes and the targeting of interventions according to risk characteristics.

The Essential Medicinal Chemistry of Cannabidiol (CBD)

This Perspective of the published essential medicinal chemistry of cannabidiol (CBD) provides evidence that the popularization of CBD-fortified or CBD-labeled health products and CBD-associated health claims lacks a rigorous scientific foundation. CBD's reputation as a cure-all puts it in the same class as other "natural" panaceas, where valid ethnobotanicals are reduced to single, purportedly active ingredients. Such reductionist approaches oversimplify useful, chemically complex mixtures in an attempt to rationalize the commercial utility of natural compounds and exploit the "natural" label. Literature evidence associates CBD with certain semiubiquitous, broadly screened, primarily plant-based substances of undocumented purity that interfere with bioassays and have a low likelihood of becoming therapeutic agents. Widespread health challenges and pandemic crises such as SARS-CoV-2 create circumstances under which scientists must be particularly vigilant about healing claims that lack solid foundational data. Herein, we offer a critical review of the published medicinal chemistry properties of CBD, as well as precise definitions of CBD-containing substances and products, distilled to reveal the essential factors that impact its development as a therapeutic agent.

Bridging research integrity and global health epidemiology (BRIDGE) guidelines: explanation and elaboration

Over the past decade, two movements have profoundly changed the environment in which global health epidemiologists work: research integrity and research fairness. Both ought to be equally nurtured by global health epidemiologists who aim to produce high quality impactful research. Yet bridging between these two aspirations can lead to practical and ethical dilemmas. In the light of these reflections we have proposed the BRIDGE guidelines for the conduct of fair global health epidemiology, targeted at stakeholders involved in the commissioning, conduct, appraisal and publication of global health research. The guidelines follow the conduct of a study chronologically from the early stages of study preparation until the dissemination and communication of findings. They can be used as a checklist by research teams, funders and other stakeholders to ensure that a study is conducted in line with both research integrity and research fairness principles. In this paper we offer a detailed explanation for each item of the BRIDGE guidelines. We have focused on practical implementation issues, making this document most of interest to those who are actually conducting the epidemiological work.

Serial measurements in COVID-19-induced acute respiratory disease to unravel heterogeneity of the disease course: design of the Maastricht Intensive Care COVID cohort (MaastrICCht)

INTRODUCTION

The course of the disease in SARS-CoV-2 infection in mechanically ventilated patients is unknown. To unravel the clinical heterogeneity of the SARS-CoV-2 infection in these patients, we designed the prospective observational Maastricht Intensive Care COVID cohort (MaastrICCht). We incorporated serial measurements that harbour aetiological, diagnostic and predictive information. The study aims to investigate the heterogeneity of the natural course of critically ill patients with a SARS-CoV-2 infection.

METHODS AND ANALYSIS

Mechanically ventilated patients admitted to the intensive care with a SARS-CoV-2 infection will be included. We will collect clinical variables, vital parameters, laboratory variables, mechanical ventilator settings, chest electrical impedance tomography, ECGs, echocardiography as well as other imaging modalities to assess heterogeneity of the course of a SARS-CoV-2 infection in critically ill patients. The MaastrICCht is also designed to foster various other studies and registries and intends to create an open-source database for investigators. Therefore, a major part of the data collection is aligned with an existing national intensive care data registry and two international COVID-19 data collection initiatives. Additionally, we create a flexible design, so that additional measures can be added during the ongoing study based on new knowledge obtained from the rapidly growing body of evidence. The spread of the COVID-19 pandemic requires the swift implementation of observational research to unravel heterogeneity of the natural course of the disease of SARS-CoV-2 infection in mechanically ventilated patients. Our study design is expected to enhance aetiological, diagnostic and prognostic understanding of the disease. This paper describes the design of the MaastrICCht.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the medical ethics committee (Medisch Ethische Toetsingscommissie 2020-1565/3 00 523) of the Maastricht University Medical Centre+ (Maastricht UMC+), which will be performed based on the Declaration of Helsinki. During the pandemic, the board of directors of Maastricht UMC+ adopted a policy to inform patients and ask their consent to use the collected data and to store serum samples for COVID-19 research purposes. All study documentation will be stored securely for fifteen years after recruitment of the last patient. The results will be published in peer-reviewed academic journals, with a preference for open access journals, while particularly considering deposition of the manuscripts on a preprint server early.

TRIAL REGISTRATION NUMBER

The Netherlands Trial Register (NL8613).

Effectiveness of pre-operative anaemia screening and increased Tranexamic acid dose policies on outcomes following unilateral primary, elective total hip or knee replacement: a statistical analysis plan for an interrupted time series and regression discontinuity study

Perioperative blood transfusion is associated with poorer postoperative outcomes following hip and knee replacement surgery. Evidence for the effectiveness of some measures aimed at reducing blood transfusions in this setting are limited and often rely on weak pre-post study designs. Quasi-experimental study designs such as interrupted time series (ITS) and regression discontinuity design (RDD) address many of the weaknesses of the pre-post study design. In addition, a priori publication of statistical analysis plans for such studies increases their transparency and likely validity, as readers are able to distinguish between pre-planned and exploratory analyses. As such, this article, written prospective of any analysis, provides the statistical analysis plan for an ITS and RDD study based on a data set of 20,772 primary elective hip and knee replacement patients in a single English NHS Trust. The primary aim is to evaluate the impact of a preoperative anaemia optimisation service on perioperative blood transfusion (within 7 days of surgery) using both ITS and RDD methods. A secondary aim is to evaluate the impact of a policy of increased tranexamic acid dose given at the time of surgery, using ITS methods.