Assessing symptom improvement in patients with postural orthostatic tachycardia syndrome (POTS) following a 16-week structured exercise programme: a protocol for a randomised cross-over trial in a clinical outpatient setting

Introduction
Exercise training is recommended as a complementary treatment in postural orthostatic tachycardia syndrome (POTS) according to international guidelines. However, less is known regarding how exercise training could successfully be implemented in clinical practice in patients with POTS. Thus, in the current study, we aim to assess the effect of a 16-week tailored exercise training programme in POTS.

Methods and analysis
A total of 200 patients diagnosed with POTS will be recruited. The study will be conducted as a randomised cross-over study. POTS symptoms will be evaluated using the Malmö POTS Symptom Score, Orthostatic Hypotension Questionnaire and 36-item Short Form Health Survey. Haemodynamic parameters will be evaluated by orthostatic tests and maximum working capacity evaluated by bicycle exercise test. Symptoms, haemodynamic parameters and exercise capacity will be assessed before and after a 16-week training programme.

Ethics and dissemination
The study was approved by the Swedish ethical review authority (2022-03186-01) and all procedures will be performed in accordance with the Helsinki Declaration. Results will be made available to patients with POTS, healthcare professionals, the funders and other researchers in publicly available (open access) medical journals.

Trial registration details
NCT05554107, registered on 26 September 2022.

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Prevalence of low-level viremia in the treatment of chronic hepatitis B in China: a systematic review and meta-analysis

Objectives
Low-level viremia (LLV) is a risk factor affecting the prognosis of patients with chronic hepatitis B (CHB). The objective of this study was to systematically assess the prevalence of LLV, thereby providing robust evidence-based medical insights into effective clinical interventions and preventative measures against LLV.

Design
Systematic review and meta-analysis.

Data sources
A comprehensive literature search was conducted across various databases, including China National Knowledge Infrastructure, Wanfang Data (Wanfang), China Science And Technology Journal Database (VIP-CSTJ), China Biology Medicine disc (CBMdisc), PubMed, Embase, Web of Science and the Cochrane Library, spanning from the inception of these databases up to 5 January 2024.

Eligibility criteria
The research type included either a cross-sectional study or a cohort study focusing on the Chinese population, with the outcome being LLV. The languages were limited to both Chinese and English. Studies with any of the following were excluded: subjects with other comorbidities, original articles inaccessible or data unavailable, and duplicate publications.

Data extraction and synthesis
Literature management used EndNote X9.1, and an information extraction table was created using Microsoft Excel to record research information, including first author, year of publication and study type. The prevalence of LLV was assessed via meta-analysis. Meta-analyses were conducted in RStudio using the ‘metaprop ()’ function. Subgroup analysis and sensitivity analysis were used to identify sources of heterogeneity, and funnel plots and AS-Thompson tests were employed to evaluate publication bias.

Results
18 studies, encompassing a total sample of 9773 patients, were included in the analysis. Of these, 3336 patients were identified with LLV. The meta-analysis revealed that the prevalence of LLV among treated CHB patients stands at 33.6% (95% CI 30.2 to 37.0). The antigen status, antiviral treatment regimen (type of drugs and nucleos(t)ide analogues (NAs)), treatment duration, medication adherence and baseline hepatitis B virus DNA levels all affected the prevalence of LLV. Sensitivity analysis further corroborated the stability of these meta-analysis findings. The funnel plot and AS-Thompson test indicated no significant publication bias (t = –0.01, p=0.995).

Conclusions
The prevalence of LLV among CHB patients was established at 33.7% (95% CI 29.8% to 37.6%). Thus, it is imperative for clinical decision-makers to consider the various influencing factors of LLV when formulating treatment plans in order to mitigate any potential adverse outcomes.

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Development and validation of an interpretable machine learning model for predicting Philadelphia chromosome-positive acute lymphoblastic leukaemia using clinical and laboratory parameters: a single-centre retrospective study

Objective
To develop and validate a prediction model of Philadelphia chromosome-positive acute lymphoblastic leukaemia (Ph+ALL).

Design
A single-centre retrospective study.

Participants
This study analysed 471 newly diagnosed patients with ALL at the Second Affiliated Hospital of Army Medical University from January 2014 to December 2023.

Methods
Clinical and laboratory parameters were collected, and the important characteristic parameters were selected using BorutaShap. Multiple machine learning (ML) models were constructed and optimised by using the active learning (AL) algorithm. Performance was evaluated using the area under the curve (AUC), comprehensive indicators and decision curve analysis. The interpretability of the model was evaluated by using SHapley Additive Interpretation (SHAP), and external validation was conducted on an independent test cohort.

Results
10 parameters were selected to construct multiple ML models. The CatBoost model integrated with an AL algorithm (CatBoost-AL) was found to be the most effective model for predicting Ph+ALL within the validation data set. This model achieved an AUC of 0.797 (95% CI 0.710 to 0.884), along with sensitivity, specificity and F1 score of 0.667, 0.864 and 0.777, respectively. The prediction performance of CatBoost-AL was further validated with an external testing set, where it maintained a strong AUC of 0.794 (95% CI 0.707 to 0.881). Using SHAP for global interpretability analysis, age, monocyte count, -glutamyl transferase, neutrophil count and alanine aminotransferase were identified as crucial parameters that significantly influence the diagnostic accuracy of CatBoost-AL.

Conclusion
An interpretable ML model and online prediction tool were developed to determine whether newly diagnosed patients with ALL are Ph+ALL. The key parameters identified by the optimal model provided a further understanding of Ph+ALL characteristics and were valuable for accurate diagnosis and treatment of Ph+ALL.

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Multicomponent intervention for controlling hypertension in the adult rural population of Pakistan: a protocol for a hybrid type III implementation-effectiveness cluster randomised controlled trial

Introduction
Though prior trials have shown the effectiveness of community-based hypertension detection and care delivery models, their adoption and translation to practice has been slow. In this study, we will develop and test strategies for the implementation and scale-up of a proven multicomponent hypertension intervention (MCHI) in Pakistan that comprises health education, blood pressure (BP) monitoring and referrals by lady health workers (LHWs) and hypertension management by physicians in primary care settings.

Methods and analysis
In this 24-month hybrid type III implementation-effectiveness cluster-randomised controlled trial, we will recruit 3000 adult hypertensive patients from two rural districts of Pakistan. We will engage public health sector managers, physicians and LHWs and use the Consolidated Framework for Implementation Research to identify barriers and facilitators to the implementation of an already proven-to-be-effective MCHI. Using Expert Recommendations for Implementing Change and the modified Delphi technique, a set of implementation strategies addressing barriers will be identified. The strategies will be categorised as level 1 (requiring a change in processes), level 2 (requiring a change in infrastructure) and level 3 (financial restructuring). Basic health units and 250–300 households from their catchment will be considered as clusters. Clusters will be randomised in a ratio of 1:1 to intervention and control. While MCHI will be offered in both trial arms (intervention and control), the aforementioned implementation strategies will be randomised to the intervention arm only, starting with level 1 and moving to levels 2 and 3 as needed. Baseline and 6-monthly follow-up surveys, each of 6 months duration, will be conducted to collect data from the recruited participants on sociodemographics, cardiovascular disease (CVD) risk factors, CVD-related expenses and quality of life. The primary outcome will be the mean difference in BP-lowering medications per participant between the intervention and control arms. The primary outcome will be analysed using a linear mixed model with fixed effects for baseline value of the outcome. Additional outcomes include implementation outcomes: proportion of LHWs conducting health education, BP screening and monitoring, facility referrals and proportion of physicians diagnosing and treating hypertensive patients; effectiveness outcomes: proportion of participants with controlled BP and improved EQ-5D-5L score.

Ethics and dissemination
Ethical approval has been obtained from the Ethics Review Committee of Aga Khan University Pakistan (ERC # 2023-9084-26739). Findings will be reported to: (1) study participants; (2) funding body and institutes collaborating and supporting the study; (3) provincial and district health departments to inform policy; (4) presented at local, national and international conferences and (5) disseminated by peer-review publications

Trial registration number
NCT06726057.

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Vitamin D levels and its influencing factors in children and adolescents in mainland China: a systematic review and meta-analysis

Objectives
Childhood vitamin D deficiency is a public health issue. This study aims to systematically evaluate vitamin D nutritional status among children and adolescents in Mainland China through a quantitative analysis of literature, providing evidence-based strategies for prevention.

Design
This is a systematic review and meta-analysis, conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

Data sources
A comprehensive search strategy was implemented across eight electronic databases (PubMed, Embase, Web of Science, Cochrane Library, CNKI, VIP, Wanfang and CBM) from inception to February 2024.

Eligibility criteria
We included cross-sectional studies that measured serum 25-hydroxyvitamin D levels and analysed influencing factors (eg, age, season, region) in healthy children and adolescents aged 0–18 years in Mainland China; studies reporting prevalence data of vitamin D deficiency/insufficiency based on standardised thresholds (deficiency

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Effects of potassium-enriched salt substitutes on blood pressure in Iranian hypertensive patients: the protocol for a randomised, double-blind controlled trial

Introduction
Potassium-enriched salt substitutes have favourable effects on blood pressure, but it has not been tested in Iran. The present protocol is a double-blinded, randomised-controlled trial designed to investigate the effects of potassium-enriched salt substitutes on blood pressure in Iranian hypertensive patients.

Methods and analysis
The primary objectives are to determine the effects on systolic and diastolic blood pressure at 3 months and 6 months. The secondary objectives are to assess the effects on serum levels of potassium, sodium, urea and creatinine; the urinary ratio of sodium to potassium; participants’ attitudes toward the use of salt or salt substitutes; the recurrence of hypertensive crisis; and the occurrence and/or reoccurrence of strokes, transient ischaemic attack and cardiovascular accidents. Eligible individuals will receive the usual salt (100% sodium chloride) in the control group or salt substitute (70% sodium chloride and 30% potassium chloride) in the intervention group. A total of 500 hypertensive participants aged 40–65 years will be recruited and randomised to intervention or control groups. Potassium-enriched salt substitution in Iran will be considered to improve CVD complications and prevent deaths. Continuous and categorical baseline characteristics will be tested using the independent t-test and 2 test. The effect of the intervention on primary and secondary outcomes will be assessed using the intention-to-treat method and two-way mixed ANOVA models.

Ethics and dissemination
This study has been approved by Alborz University of Medical Sciences (0-0-103-6369) and has received ethics approval (IR.ABZUMS.REC.1402.293). We will publish our study findings for peer-reviewed publications, conference presentations and digital stories.

Trial registration number
IRCT20240121060757N1.

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Development and validation of critical appraisal tool for individual participant data meta-analysis: protocol for a modified e-Delphi study

Introduction
Individual participant data meta-analysis (IPD-MA) is regarded as the gold standard for evidence synthesis. However, diverse recommendations and guidance on its conduct exist, and there is no consensus-based tool for the critical appraisal of a completed IPD-MA. We aim to close this gap by systematically identifying quality items and developing and validating a critical appraisal checklist for IPD-MA.

Methods and analysis
This study will comprise three phases, as follows:
Phase 1: a systematic methodology review to identify potential checklist domains and items; this will be conducted according to the Cochrane methods for systematic reviews and reported following the Preferred Reporting Items for Systematic Reviews and Meta-analysis 2020 guidance. We will include studies that address methodological guides and essential statistical requirements for IPD-MA. We will use the proposed items to prepare a preliminary checklist for the e-Delphi study.
Phase 2: at least two rounds of an e-Delphi survey will be conducted among panels with expertise in IPD-MA research, consensus development, healthcare providers, journal editors, healthcare policymakers, patients and public partners from diverse geographic locations with experience in IPD-MA. Participants will use Qualtrics software to rate items on a 5-point Likert scale. The Wilcoxon matched signed rank test will estimate response stability across rounds. Consensus on including an item will be achieved if ≥75% of the panel rates the item as ‘strongly agree’ or ‘agree’ and items will be excluded if ≥75% rates it as ‘strongly disagree’ or ‘disagree’. A convenience sample of 10 reviewers with experience in conducting an IPD-MA will pilot-test the checklist to provide practical feedback that will be used to refine the checklist.
Phase 3: critical appraisal checklist validation: to improve confidence in the tool’s uptake, a subset of the e-Delphi participants and graduate students of epidemiology and biostatistics will conduct content validity and reliability testing, respectively, per the Consensus-based Standards for the Selection of Health Measurement Instruments.

Ethics and dissemination
Ethics approval has been obtained from the Western University Health Science Research Ethics Board in Canada. The validated checklist will be published in a peer-reviewed open-access journal and shared across the networks of this study’s steering committee, Cochrane IPD-MA group and the institutions’ social media platforms.

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