Category: Statistics

J Educ Eval Health Prof. 2021;18:17. doi: 10.3352/jeehp.2021.18.17. Epub 2021 Jul 30.

ABSTRACT

Appropriate sample size calculation and power analysis have become major issues in research and publication processes. However, the complexity and difficulty of calculating sample size and power require broad statistical knowledge, there is a shortage of personnel with programming skills, and commercial programs are often too expensive to use in practice. The review article aimed to explain the basic concepts of sample size calculation and power analysis; the process of sample estimation; and how to calculate sample size using G*Power software (latest ver. 3.1.9.7; Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany) with 5 statistical examples. The null and alternative hypothesis, effect size, power, alpha, type I error, and type II error should be described when calculating the sample size or power. G*Power is recommended for sample size and power calculations for various statistical methods (F, t, χ2, Z, and exact tests), because it is easy to use and free. The process of sample estimation consists of establishing research goals and hypotheses, choosing appropriate statistical tests, choosing one of 5 possible power analysis methods, inputting the required variables for analysis, and selecting the “Calculate” button. The G*Power software supports sample size and power calculation for various statistical methods (F, t, χ2, z, and exact tests). This software is helpful for researchers to estimate the sample size and to conduct power analysis.

PMID:34325496 | DOI:10.3352/jeehp.2021.18.17

Crit Care Med. 2021 Jul 29. doi: 10.1097/CCM.0000000000005144. Online ahead of print.

ABSTRACT

OBJECTIVE: To systematically review and meta-analyze the validity of electrical bioimpedance-based noninvasive cardiac output monitoring in pediatrics compared with standard methods such as thermodilution and echocardiography.

DATA SOURCES: Systematic searches were conducted in MEDLINE and EMBASE (2000-2019).

STUDY SELECTION: Method-comparison studies of transthoracic electrical velocimetry or whole body electrical bioimpedance versus standard cardiac output monitoring methods in children (0-18 yr old) were included.

DATA EXTRACTION: Two reviewers independently performed study selection, data extraction, and risk of bias assessment. Mean differences of cardiac output, stroke volume, or cardiac index measurements were pooled using a random-effects model (R Core Team, R Foundation for Statistical Computing, Vienna, Austria, 2019). Bland-Altman statistics assessing agreement between devices and author conclusions about inferiority/noninferiority were extracted.

DATA SYNTHESIS: Twenty-nine of 649 identified studies were included in the qualitative analysis, and 25 studies in the meta-analyses. No significant difference was found between means of cardiac output, stroke volume, and cardiac index measurements, except in exclusively neonatal/infant studies reporting stroke volume (mean difference, 1.00 mL; 95% CI, 0.23-1.77). Median percentage error in child/adolescent studies approached acceptability (percentage error less than or equal to 30%) for cardiac output in L/min (31%; range, 13-158%) and stroke volume in mL (26%; range, 14-27%), but not in neonatal/infant studies (45%; range, 29-53% and 45%; range, 28-70%, respectively). Twenty of 29 studies concluded that transthoracic electrical velocimetry/whole body electrical bioimpedance was noninferior. Transthoracic electrical velocimetry was considered inferior in six of nine studies with heterogeneous congenital heart disease populations.

CONCLUSIONS: The meta-analyses demonstrated no significant difference between means of compared devices (except in neonatal stroke volume studies). The wide range of percentage error reported may be due to heterogeneity of study designs, devices, and populations included. Transthoracic electrical velocimetry/whole body electrical bioimpedance may be acceptable for use in child/adolescent populations, but validity in neonates and congenital heart disease patients remains uncertain. Larger studies in specific clinical contexts with standardized methodologies are required.

PMID:34325447 | DOI:10.1097/CCM.0000000000005144

J Am Geriatr Soc. 2021 Jul 29. doi: 10.1111/jgs.17384. Online ahead of print.

ABSTRACT

BACKGROUND: Older adults with similar health conditions often experience widely divergent outcomes following health stressors. Variable recovery after a health stressor may be due in part to differences in biological mechanisms at the molecular, cellular, or system level, that are elicited in response to stressors. We describe the PRIME-KNEE study as an example of ongoing research to validate provocative clinical tests and biomarkers that predict resilience to specific health stressors.

METHODS: PRIME-KNEE is an ongoing, prospective cohort study that will enroll 250 adults ≥60 years undergoing total knee arthroplasty. Data are collected at baseline (pre-surgery), during surgery, daily for 7 days after surgery, and at 1, 2, 4, and 6 months post-surgery. Provocative tests include a cognition-motor dual-task walking test, cerebrovascular reactivity assessed by functional near-infrared spectroscopy, peripheral blood mononuclear cell reactivity ex vivo to lipopolysaccharide toxin and influenza vaccine, and heart rate variability during surgery. Cognitive, psychological, and physical performance batteries are collected at baseline to estimate prestressor reserve. Demographics, medications, comorbidities, and stressor characteristics are abstracted from the electronic medical record and via participant interview. Blood-based biomarkers are collected at baseline and postoperative day 1. Repeated measures after surgery include items from a delirium assessment tool and pain scales administered daily by telephone for 7 days and cognitive change index (participant and informant), lower extremity activities of daily living, pain scales, and step counts assessed by Garmin actigraphy at 1, 2, 4, and 6 months after surgery. Statistical models use these measures to characterize resilience phenotypes and evaluate prestressor clinical indicators associated with poststressor resilience.

CONCLUSION: If PRIME-KNEE validates feasible clinical tests and biomarkers that predict recovery trajectories in older surgical patients, these tools may inform surgical decision-making, guide pre-habilitation efforts, and elucidate mechanisms underlying resilience. This study design could motivate future geriatric research on resilience.

PMID:34325481 | DOI:10.1111/jgs.17384

J Educ Eval Health Prof. 2021;18:16. doi: 10.3352/jeehp.2021.18.16. Epub 2021 Jul 30.

ABSTRACT

PURPOSE: Simulation teaching refers to the replication of real-life scenarios, enabling students to practice nursing skills and learn actively in a safe environment. It also helps students control their anxiety and fears when caring for real patients. This study investigated the relationships of Vietnamese nursing students’ self-confidence in clinical practice with their satisfaction and self-confidence in simulation-based practice.

METHODS: This cross-sectional descriptive study included 182 nursing students. The data collection included 2 separate stages with 2 main questionnaires. The Student Satisfaction and Self-Confidence in Learning Scale was used to measure students’ satisfaction and self-confidence after learning in the simulation room. The Confidence Scale was used to measure students’ self-confidence when first performing techniques on actual patients. Data were analyzed by descriptive and Pearson correlation statistics.

RESULTS: Students’ satisfaction and self-confidence during the simulation course were quite high (mean±standard deviation [SD], 4.06±0.48 and 4.11±0.46 out of 5.0, respectively). In contrast, their confidence when first practicing on a patient was moderate (mean±SD, 3.19±0.62 out of 5.0). Students’ satisfaction showed moderate and weak positive correlations with self-confidence in pre-clinical practice and in clinical practice (r=0.33, P<0.001 and r=0.26, P<0.001, respectively).

CONCLUSION: Simulation has become an effective teaching strategy that can help nursing students be well-prepared for clinical placements in Vietnam. An effective nursing education strategy is needed to enhance the satisfaction and self-confidence of nursing students in simulation and then in clinical practice to help achieve professional engagement and development.

PMID:34325495 | DOI:10.3352/jeehp.2021.18.16

J Occup Environ Med. 2021 Jul 27. doi: 10.1097/JOM.0000000000002336. Online ahead of print.

ABSTRACT

OBJECTIVE: To investigate whether health care workers’ (HCWs) return to work (RTW) after coronavirus disease 2019 (COVID-19) was associated with time to a negative viral detection test.

METHODS: To evaluate the association of return to work (RTW) with an undetectable RT-PCR adjusting for different factors.

RESULTS: 375 HCWs who required medical leave for COVID-19 at a hospital in Madrid. Multivariable analyses confirmed the association of delayed RTW with interval to negative PCR (ORadj 1.12, 95% CI 1.08, 1.17) as well as age, sex, and nursing staff and clinical support services compared to physicians. A predictive model based on those variables is proposed, which had an area under the receiver operating curve of 0.82.

CONCLUSIONS: Delayed RTW was associated with longer interval to a negative RT-PCR after symptom onset, adjusting for occupational category, age, and sex.

PMID:34325436 | DOI:10.1097/JOM.0000000000002336

J Pediatr Orthop. 2021 Jul 29. doi: 10.1097/BPO.0000000000001853. Online ahead of print.

ABSTRACT

BACKGROUND: Accurate assessments of skeletal maturity is of critical importance to guide type and timing of orthopaedic surgical interventions. Several quantitative markers of the proximal tibia were recently developed using historical knee radiographs. The purpose of the present study was to determine which marker would be most effective in assessment of full-length radiographs in a modern pediatric patient population.

METHODS: All full-length radiographs at our institutions between 2013 and 2018 were reviewed. Inclusion criteria for our study required that the child reached final height as defined by 2 consecutive unchanged heights, at least 6 months apart, after age 16 for boys and 14 for girls. Patients with metabolic bone disease, prior surgery such as epiphysiodesis, or previous infections around the knee were excluded. Summary statistics for each of the 3 proximal tibial ratios were calculated and multiple linear regression was performed with percent of growth remaining as a dependent variable. A recommended regression model is presented and evaluated.

RESULTS: A total of 692 full-length radiographs met inclusion criteria. Proximal tibial ratios were calculated and averaged values for each percent of growth remaining was presented. Multiple linear regression demonstrated that using all 3 variables led to overfitting of the model so tibial metaphyseal width/lateral tibial epiphyseal height was selected as the optimal ratio for use by clinicians. The optimal model for determining growth was found to have R2=0.723 in the developmental set and R2=0.762 in an excluded validation set.

CONCLUSIONS: This study demonstrates that the proximal tibial metaphyseal width/lateral tibial epiphyseal height is the ideal measurement for clinicians seeking to determine growth remaining in children. It presents average values between 0% and 25% of growth remaining. This study also develops and validates a multivariable regression model for determining percentage of growth remaining in children that will allow for quantitative determination of growth using full-length radiographs.

LEVEL OF EVIDENCE: Level III.

PMID:34325444 | DOI:10.1097/BPO.0000000000001853

Gerontology. 2021 Jul 29:1-8. doi: 10.1159/000514678. Online ahead of print.

ABSTRACT

INTRODUCTION: Anemia is a common condition encountered in acute ischemic stroke, and only a few pieces of evidence has been produced suggesting its possible association with short-term mortality have been produced. The study sought to assess whether admission anemia status had any impact on short-term clinical outcome among oldest-old patients with acute ischemic stroke.

MATERIALS AND METHODS: A retrospective review of Electronic Medical Recording System was performed in 2 tertiary hospitals. Data, from the oldest-old patients aged > = 80 years consecutively admitted with a diagnosis of acute ischemic stroke between January 1, 2015, and December 31, 2019, were analyzed. Admission hemoglobin was used as indicator for anemia and severity. Univariate and multivariate regression analyses were used to compare in-hospital mortality and length of in-hospital stay in different anemia statuses and normal hemoglobin patients.

RESULTS: A total of 705 acute ischemic stroke patients were admitted, and 572 were included in the final analysis. Of included patients, 240 of them were anemic and 332 nonanemic patients. A statistical difference between the 2 groups was found in in-hospital mortality (p < 0.001). After adjustment for baseline characteristics, the odds ratio value of anemia for mortality were 3.91 (95% confidence intervals (CI) 1.60-9.61, p = 0.003) and 7.15 (95% CI: 1.46-34.90, p = 0.015) in moderate and severely anemic patients, respectively. Similarly, length of in-hospital stay was longer in anemic patients (21.64 ± 6.17 days) than in nonanemic patients (19.08 ± 5.48 days, p < 0.001).

CONCLUSIONS: Increased severity of anemia may be an independent risk factor for increased in-hospital mortality and longer length of stay in oldest-old patients with acute ischemic stroke.

PMID:34325428 | DOI:10.1159/000514678

Eur Neurol. 2021 Jul 29:1-10. doi: 10.1159/000517584. Online ahead of print.

ABSTRACT

BACKGROUND: Previous studies have shown inconsistent results for associations between vitamin D and risk of stroke. We gathered the existing published articles and conducted this meta-analysis with the aim to explore the association between vitamin D and risk of stroke.

METHODS: We searched for articles exploring the association between vitamin D and risk of stroke and published before April 2021 in the following databases: PubMed, Web of Science, MEDLINE, EMBASE, and Google Scholar. All statistical analyses were made using STATA 12.0 software. Q test and I2 were applied to examine heterogeneities between studies.

RESULTS: For the association between serum levels of 25(OH) vitamin D and risks of stroke, the present analysis included 20 cohort studies (including 213,276 participants) and a case-control analysis (including 13,642 participants). Additionally, the analysis included 15 studies (including 41,146 participants given vitamin D supplementation and 41,163 participants given placebo) to evaluate the influence of vitamin D supplementation on risk of stroke. Higher circulating levels of 25(OH) vitamin D were associated with a reduced risk of stroke (odds ratio/relative risk = 0.78, 95% confidence interval [CI]: 0.70-0.86, I2 = 41.5%, p = 0.025). However, the present analysis showed that vitamin D supplementation did not influence the risk of stroke (hazard ratio = 1.05, 95% CI: 0.96-1.14, I2 = 2.3%, p = 0.425).

CONCLUSIONS: Our analysis indicated that lower circulating level of vitamin D was associated with an elevated risk of stroke, but extra supplement of vitamin D failed to show benefit in decreasing the risk of stroke. Further research and study are also needed to show the role of vitamin D in relation to stroke.

PMID:34325429 | DOI:10.1159/000517584

ORL J Otorhinolaryngol Relat Spec. 2021 Jul 29:1-8. doi: 10.1159/000516592. Online ahead of print.

ABSTRACT

INTRODUCTION: Thyroglossal duct cysts (TGDCs) are the most common form of congenital neck cysts. They may become infected causing dysphagia or respiratory distress. Accordingly, the treatment is always surgical removal.

OBJECTIVES: The objectives of this article were to examine complications following TGDC excision by surgical specialty, demographics, and comorbid conditions.

METHODS: A retrospective review of the National Surgical Quality Improvement Program database was performed. Pediatric cases from January 1, 2014 to November 1, 2015 with a current procedure terminology code of 60,280 (excision of TGDC or sinus) were included. Statistical analysis was performed to assess associations between complications and surgical specialty, demographics, and comorbidities.

RESULTS: Of the 867 cases that met inclusion criteria, the median age was 4 years. There were 448 males (52.3%) and 408 females (47.7%). Thirty-six patients (4.2%) experienced at least one 30-day complication. The most predominant complications were reoperation (19 patients, 2.2%), readmission (18 patients, 2.1%), and surgical site infection (16 patients, 1.9%). There was no statistically significant difference between complications and surgical specialty. In those experiencing a complication, there was a statistically significant difference between males (86.1%) and females (13.9%). Of patients with at least one comorbidity, 36.67% had a complication, while 17.22% did not have a complication. There was also a statistically significant difference in the percentage of patients with a past medical history of asthma between those with at least one complication (16.67%) compared to those without any complications (4.76%).

CONCLUSIONS: excision is a generally safe procedure across surgical specialties. There is a higher complication rate in males compared to females as well as those with a history of at least one medical comorbidity and those with asthma. The most common 30-day complications are reoperation, readmission, and surgical site infection.

PMID:34325433 | DOI:10.1159/000516592

Curr Opin Pharmacol. 2021 Jul 26;60:34-39. doi: 10.1016/j.coph.2021.06.006. Online ahead of print.

ABSTRACT

Biophysically realistic computer modeling of neuronal microcircuitry has served as a testing ground for hypotheses related to the structure and function of different brain microcircuits. Recent advances in single-cell transcriptomics provide snapshots of a neuron’s molecular state and have demonstrated that cell-specific genetic markers engineer the electrophysiological properties of a neuron. Integrating these molecular details with biophysical modeling can allow unprecedented mechanistic insights. In this opinion review, we consider systems biology-based strategies involving statistical deconvolution and gene ontology to integrate the two approaches. We foresee that this integration will infer the nonlinear interactions between the transcriptomically detailed neurons in different brain states. For an initial assessment of these integrative strategies, we recommend testing them on a penetrant phenotype such as epilepsy or a basic organism model such as Caenorhabditis elegans.

PMID:34325379 | DOI:10.1016/j.coph.2021.06.006