Study designs: Part 3 - Analytical observational studies

Methodological and Statistical Considerations for Cross-Sectional, Case-Control, and Cohort Studies

Epidemiological studies are essential in medicine and public health as they help identify risk factors and causes of diseases. Additionally, they are key to planning, implementing, and evaluating health interventions aimed at preventing and controlling the spread of diseases. Among these studies, analytical observational studies, such as cross-sectional, case-control, and cohort studies, are the most used. The validity of their results largely depends on the robustness of the design, execution, and statistical analysis. Objective: The objective of this study is to examine the most common errors in the selection of methodological design and statistical tests in analytical observational studies and to provide recommendations to correct them. Methodology: A comprehensive review of the available literature on methodology in epidemiological observational studies was conducted, focusing on cross-sectional, case-control, and cohort studies. Common errors in the selection of designs and statistical tests were identified and analyzed. Results and Conclusions: Errors in the selection of methodological design and statistical tests are common in epidemiological observational studies. Based on the identified errors, a series of recommendations is provided to improve the selection of methodological design and statistical tests, thereby increasing the reliability of the results in cross-sectional, case-control, and cohort studies.

Sample size calculation in clinical research

Calculation of sample size is an essential part of research study design since it affects the reliability and feasibility of the research study. In this article, we look at the principles of sample size calculation for different types of research studies.

Interventions to change antimicrobial use in livestock: A scoping review and an impact pathway analysis of what works, how, for whom and why

Antimicrobial resistance (AMR) is a public health threat responsible for 700,000 deaths per year worldwide. Antimicrobial use (AMU) in livestock contributes to AMR in animal and public health. Therefore, it is essential to implement effective interventions towards better AMU in livestock. However, there is a lack of evidence to inform decision-makers of what works, how, for whom and why and how effective interventions can be adapted to different contexts. We conducted a scoping review and an impact pathway analysis to systematically map the research done in this area and to inform evidence-based and context-appropriate policies. We followed the PRISMA-ScR requirements and searched Web of Science, PubMed and Scopus databases to identify studies in English or French languages, in open access and published between 2000 and 2022. We selected thirty references addressing twenty-eight different interventions that were successful in changing AMU in livestock. We used an impact pathway logic model as an analytic framework to guide the technical aspects of the scoping review process and to identify the complex relationships between outputs, outcomes, impacts and contextual factors. A majority of interventions managed to improve AMU by changing herd and health management practices (ni=18). We identified intermediate outcomes including change in the veterinarian-farmer relationship (ni=7), in knowledge and perception (ni=6), and in motivation and confidence (ni=1). Twenty-two studies recorded positive impacts on animal health and welfare (ni=11), technical performances (ni=9), economic performances (ni=4) and AMR reduction (ni=4). Interventions implemented different strategies including herd and health management support (ni=20), norms and standards (ni=11), informational and educational measures (ni=10), economic support (ni=5). Studies were mainly in European countries and in pig and large ruminants farming. Most interventions targeted farmers or veterinarians but we identified other major and influential actors including authority and governmental organizations, academics and research, organization of producers or veterinarians, herd advisors and technicians, laboratories, and public opinion. Key success factors were knowledge and perception (ni=14), social factors (ni=13), intervention characteristics (ni=11), trajectory and ecosystem of change (ni=11), economic factors (ni=9), herd and health status (ni=8), data access and monitoring (ni=4). This review describes a paucity of impact assessment of interventions towards better AMU in livestock. There is no one-size-fits-all transition pathway but we inform decision-makers about the most successful interventions that work, how, for whom and why. The impact pathway analysis provided a holistic view of the successful change processes and the complex relationships between outputs, outcomes, impacts and contexts.

Risk of repeated suicide attempt after redeeming prescriptions for antidepressants: a register-based study in Denmark

BACKGROUND

It remains unclear how SSRIs and other antidepressants are associated with the risk of repeated suicide attempts. We aimed to analyse the association between redeemed antidepressant prescriptions and the risk of repeated suicide attempts, hypothesising that antidepressant treatment is associated with increased risk of repeated suicide attempts.

METHODS

The study was based on Danish register data and a validated cohort of 1842 suicide attempts. We used three Cox regression models (crude, adjusted and propensity score matched) to analyse the data; these models included both static and dynamic time-dependent factors.

RESULTS

1842 individuals attempted suicide in the study period, with a total of 210 repeated attempts. Individuals redeeming antidepressant prescriptions were more likely to repeat a suicide attempt. All crude models showed all antidepressants to be significant risk factors (HR around 1.39), whereas all adjusted models showed all antidepressants to be insignificant risk factors.

CONCLUSION

We found no significant increased risk of repeated suicide attempts in individuals redeeming a prescription for any antidepressant (or only SSRIs) when considering the individuals' baseline risk of repetition. This study is based on validated suicide attempts, register data, and strong epidemiology designs, but it still has some limitations, and the results should be replicated and confirmed in other studies.

A Multidisciplinary Approach to Swallowing Rehabilitation in Patients with Forward Head Posture

(1) Background and Objectives: The forward head posture (FHP) is characterized by increased extensions of upper cervical vertebrae and flexion of the lower cervical vertebrae and upper thoracic regions, associated with muscle shortening. The compressive loading on the tissues in the cervical spine negatively impacts suprahyoid and infrahyoid muscles and generates increased tension of the masticatory muscles. The tongue has relations with the suprahyoid and the infrahyoid muscles. The pattern of swallowing evolves gradually from birth to the age of four. If this developmental transition does not occur, the result is persistent infantile or atypical swallowing-an orofacial myofunctional disorder with the tongue in improper position during swallowing, causing strain and stress on the jaw, face, head and neck. In FHP, muscles crucial to swallowing are biomechanically misaligned. The lengthening of the suprahyoid muscles necessitates stronger contractions to achieve proper hyolaryngeal movement during swallowing. This study assesses the added benefits of physiotherapy to the traditional myofunctional swallowing rehabilitation for patients with FHP. The underlying hypothesis is that without addressing FHP, swallowing rehabilitation remains challenged and potentially incomplete. (2) Materials and Methods: A total of 61 participants (12-26 years) meeting the inclusion criteria (FHP and atypical swallowing) were divided into two similar groups. Group A attended one orofacial myofunctional therapy (OMT) and one physiotherapy session per week, group B only one OMT session per week, for 20 weeks. Exclusion criteria were as follows: ankyloglossia, neurological impairment affecting tongue and swallowing, cervical osteoarticular pathology, other previous or ongoing treatments for FHP and atypical swallowing. (3) Results: There is a significant improvement in terms of movement and use of the orofacial structures (tongue, lips, cheeks), as well as in breathing and swallowing in both groups. Group A achieved better outcomes as the CVA angle was directly addressed by manual therapy and GPR techniques. (4) Conclusions: The combined therapy proved to be more effective than single OMT therapy.

Computerized Clinical Decision Support Systems for the Early Detection of Sepsis Among Adult Inpatients: Scoping Review

Background

Sepsis is a significant cause of morbidity and mortality worldwide. Early detection of sepsis followed promptly by treatment initiation improves patient outcomes and saves lives. Hospitals are increasingly using computerized clinical decision support (CCDS) systems for the rapid identification of adult patients with sepsis.

Objective

This scoping review aims to systematically describe studies reporting on the use and evaluation of CCDS systems for the early detection of adult inpatients with sepsis.

Methods

The protocol for this scoping review was previously published. A total of 10 electronic databases (MEDLINE, Embase, CINAHL, the Cochrane database, LILACS [Latin American and Caribbean Health Sciences Literature], Scopus, Web of Science, OpenGrey, ClinicalTrials.gov, and PQDT [ProQuest Dissertations and Theses]) were comprehensively searched using terms for sepsis, CCDS, and detection to identify relevant studies. Title, abstract, and full-text screening were performed by 2 independent reviewers using predefined eligibility criteria. Data charting was performed by 1 reviewer with a second reviewer checking a random sample of studies. Any disagreements were discussed with input from a third reviewer. In this review, we present the results for adult inpatients, including studies that do not specify patient age.

Results

A search of the electronic databases retrieved 12,139 studies following duplicate removal. We identified 124 studies for inclusion after title, abstract, full-text screening, and hand searching were complete. Nearly all studies (121/124, 97.6%) were published after 2009. Half of the studies were journal articles (65/124, 52.4%), and the remainder were conference abstracts (54/124, 43.5%) and theses (5/124, 4%). Most studies used a single cohort (54/124, 43.5%) or before-after (42/124, 33.9%) approach. Across all 124 included studies, patient outcomes were the most frequently reported outcomes (107/124, 86.3%), followed by sepsis treatment and management (75/124, 60.5%), CCDS usability (14/124, 11.3%), and cost outcomes (9/124, 7.3%). For sepsis identification, the systemic inflammatory response syndrome criteria were the most commonly used, alone (50/124, 40.3%), combined with organ dysfunction (28/124, 22.6%), or combined with other criteria (23/124, 18.5%). Over half of the CCDS systems (68/124, 54.8%) were implemented alongside other sepsis-related interventions.

Conclusions

The current body of literature investigating the implementation of CCDS systems for the early detection of adult inpatients with sepsis is extremely diverse. There is substantial variability in study design, CCDS criteria and characteristics, and outcomes measured across the identified literature. Future research on CCDS system usability, cost, and impact on sepsis morbidity is needed.

International Registered Report Identifier (IRRID)

RR2-10.2196/24899

Corneal ectasia in mothers of Down syndrome children

In this study, corneal findings regarding keratoconus (KC) and early KC among mothers with Down syndrome children (MDS) and a group of age-at-delivery-matched mothers with normal children (MNC) were compared. KC was diagnosed based on the presence of a clinical sign and at least one abnormal tomographic or biomechanical criterion. Early KC was defined as having no clinical sign in the presence of at least one abnormal tomographic or biomechanical criterion. The normal subgroups in each group were compared in terms tomographic and biomechanical parameters. In MDS and MNC, the prevalence rates were 6.5% and 1.6% for KC (P = 0.047), and 30.9% and 14.3% for early KC (P = 0.014), respectively. Comparison between the two normal subgroups showed significant differences in mean index of height asymmetry, irregularity index, anterior asphericity, pentacam random forest index, corneal stiffness parameters at first applanation, deformation amplitude ratios, integrated radius-1 mm, highest concavity deflection amplitude, biomechanical corrected IOP, peak distance, and radius (all P < 0.05). This study showed that MDS are more likely to have KC and also to have thinner, steeper and softer corneas compared to MNC. This results support the need for further work for determining the risk of delivering a child with DS.

Association between primary headaches and temporomandibular disorders: A systematic review and meta-analysis

BACKGROUND

The primary objective of this systematic review was to answer the following question systematically: Is there any association between primary headaches (PHs) and temporomandibular disorders (TMDs) in adults?

TYPES OF STUDIES REVIEWED

The protocol was registered with the International Prospective Register of Systematic Reviews. The authors performed the search in 7 main databases and 3 gray literature sources. The included articles had to have adult samples. PHs must have been diagnosed using the International Classification of Headache Disorders, and TMDs must have been diagnosed using Research Diagnostic Criteria for Temporomandibular Disorders, Diagnostic Criteria for Temporomandibular Disorders, or International Classification of Orofacial Pain. Risk of bias was evaluated using the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument tools. The meta-analysis was performed using Review Manager software, Version 5.4. Certainty of evidence was screened according to Grading of Recommendations Assessment, Development and Evaluation.

RESULTS

Eight of 2,574 articles reviewed met the inclusion criteria for qualitative analysis and, of these, 6 met the inclusion criteria for quantitative analysis. Odds ratios (ORs) for painful TMD and tension-type headache (OR, 3.16; 95% CI, 1.80 to 5.54 to OR, 13.06; 95% CI, 2.79 to 61.12), migraines (OR, 5.35; 95% CI, 3.04 to 9.40 to OR, 6.22; 95% CI, 3.81 to 10.14), and chronic headaches (OR, 40.40; 95% CI, 8.67 to 188.15 to OR, 95.93; 95% CI, 12.53 to 734.27) were calculated. Articular TMDs without pain were evaluated in only 1 article, in which ORs of 1.78 (95% CI, 0.90 to 3.51) for migraines and 1.04 (95% CI, 0.53 to 2.06) for tension-type headache were reported. Three studies were classified as moderate risk of bias and 5 as low risk of bias. The certainty of evidence varied between very low and low.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

Recognizing the positive association between painful TMD and PHs can help dentists and physicians treat the pain and avoid it, or recommend the patient to a specialist.

Real-time locating systems to improve healthcare delivery: A systematic review

OBJECTIVE

Modern health care requires patients, staff, and equipment to navigate complex environments to deliver quality care efficiently. Real-time locating systems (RTLS) are local tracking systems that identify the physical locations of personnel and equipment in real time. Applications and analytic strategies to utilize RTLS-produced data are still under development. The objectives of this systematic review were to describe and analyze the key features of RTLS applications and demonstrate their potential to improve care delivery.

MATERIALS AND METHODS

We searched MEDLINE, SCOPUS, and IEEE following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Inclusion criteria were articles that utilize RTLS to evaluate or influence workflow in a healthcare setting. We summarized aspects of relevant articles, identified key themes in the challenges of applying RTLS to workflow improvement, and thematically reviewed the state of quantitative analytic methodologies.

RESULTS

We included 42 articles in the final qualitative synthesis. The most frequent study design was observational (n = 24), followed by descriptive (n = 12) and experimental (n = 6). The most common clinical environment for study was the emergency department (n = 12), followed by entire hospital (n = 7) and surgical ward (n = 6).

DISCUSSION

The focus of studies changed over time from early experience to optimization to evaluation of an established system. Common narrative themes highlighted lessons learned regarding evaluation, implementation, and information visibility. Few studies have developed quantitative techniques to effectively analyze RTLS data.

CONCLUSIONS

RTLS is a useful and effective adjunct methodology in process and quality improvement, workflow analysis, and patient safety. Future directions should focus on developing enhanced analysis to meaningfully interpret RTLS data.

Genetic variations in the human immune system influence susceptibility to tegumentary leishmaniasis: a systematic review and meta-analysis

OBJECTIVES

The outcomes of tegumentary leishmaniasis (TL) rely on a complex interaction between the host immune system and the parasite. This study assessed the influence of polymorphisms in immune-related genes on TL.

METHODS

Web of Science, Scopus, PubMed, and Embase databases were searched systemically. The meta-analysis used a retrospective model in examining alleles, heterozygotes, and homozygotes. A quality assessment and an analysis of cumulative evidence were performed.

RESULTS

A total of 29 genes (encoding for cytokines, chemokines, and other immune receptors) and 84 polymorphisms were analyzed. The IL-1β_rs16944 (OR = 1.341, p = 0.003), TNF-α_rs1800629 (OR = 3.804, p = 0.004), MIF_rs755622 (OR = 3.357, p = 0.001), and INF- γ_rs243056 (OR = 1.670, p = 0.028) polymorphisms were speculated as risk factor for TL. They decrease the expression of the corresponding genes crucial for TL control. The quality assessment score was approximately 50%, suggesting the need for a clear method and polymorphism characterization for further comparison. The relevant risk of bias and other considerations resulted in low and moderate cumulative evidence confidence.

CONCLUSIONS

IL-1β_rs16944, TNF-α_rs1800629, MIF_rs755622, and INF-γ_rs2430561 polymorphisms were speculated as risk factor for TL, corroborating that IL-1β, TNF-α, INF-γ, and MIF are involved in the TL pathogenesis.

Use and Evaluation of Computerized Clinical Decision Support Systems for Early Detection of Sepsis in Hospitals: Protocol for a Scoping Review

BACKGROUND

Sepsis is a leading cause of death in hospitals, with high associated costs for both patients and health care systems worldwide. Early detection followed by timely intervention is critical for successful sepsis management and, hence, can save lives. Health care institutions are increasingly leveraging clinical data captured in electronic health records for the development of computerized clinical decision support (CCDS) systems aimed at enhancing the early detection of sepsis. However, a comprehensive evidence base regarding sepsis CCDS systems to inform clinical practice, research, and policy is currently lacking.

OBJECTIVE

This scoping review aims to systematically describe studies reporting on the use and evaluation of CCDS systems for early detection of sepsis in hospitals.

METHODS

The methodology for conducting scoping reviews presented by the Joanna Briggs Institute Reviewer's Manual and the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews) will be used and adapted as guides. A comprehensive literature search of 10 electronic databases will be conducted to identify all empirical quantitative and qualitative studies that investigate the use of CCDS systems for early detection of sepsis in hospitals. Detailed inclusion and exclusion criteria have been developed. Two reviewers will independently screen all articles based on these criteria. Any discrepancies will be resolved through discussion and further review by a third researcher if required.

RESULTS

Electronic database searches have retrieved 12,139 references after removing 10,051 duplicates. As of the submission date of this protocol, we have completed the title and abstract screening. A total of 372 references will be included for full-text screening. Only 15.9% (59/372) of these studies were focused on children: 11.0% (41/372) for pediatric and 4.8% (18/372) for neonatal patients. The scoping review and the manuscript will be completed by December 2020.

CONCLUSIONS

Results of this review will guide researchers in determining gaps and shortcomings in the current evidence base for CCDS system use and evaluation in the early detection of sepsis. The findings will be shared with key stakeholders in clinical care, research, policy, and patient advocacy.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/24899.

Study designs: Part 4 - Interventional studies

In the fourth piece of this series on research study designs, we look at interventional studies (clinical trials). These studies differ from observational studies in that the investigator decides whether or not a participant will receive the exposure (or intervention). In this article, we describe the key features and types of interventional studies.