Sample size calculation: Basic principles

Primary outcomes and anticipated effect sizes in randomised clinical trials assessing adjuncts to peripheral nerve blocks: A scoping review

BACKGROUND

Prolonging effects of adjuncts to local anaesthetics in peripheral nerve blocks have been demonstrated in randomised clinical trials. The chosen primary outcome and anticipated effect size have major impact on the clinical relevance of results in these trials. This scoping review aims to provide an overview of frequently used outcomes and anticipated effect sizes in randomised trials on peripheral nerve block adjuncts.

METHODS

For our scoping review, we searched MEDLINE, Embase and CENTRAL for trials assessing effects of adjuncts for peripheral nerve blocks published in 10 major anaesthesia journals. We included randomised clinical trials assessing adjuncts for single-shot ultrasound-guided peripheral nerve blocks, regardless of the type of interventional adjunct and control group, local anaesthetic used and anatomical localization. Our primary outcome was the choice of primary outcomes and corresponding anticipated effect size used for sample size estimation. Secondary outcomes were assessor of primary outcomes, the reporting of sample size calculations and statistically significant and non-significant results related to the anticipated effect sizes.

RESULTS

Of 11,854 screened trials, we included 59. The most frequent primary outcome was duration of analgesia (35/59 trials, 59%) with absolute and relative median (interquartile range) anticipated effect sizes for adjunct versus placebo/no adjunct: 240 min (180-318) and 30% (25-40) and for adjunct versus active comparator: 210 min (180-308) and 17% (15-28). Adequate sample size calculations were reported in 78% of trials. Statistically significant results were reported for primary outcomes in 45/59 trials (76%), of which 22% did not reach the anticipated effect size.

CONCLUSION

The reported outcomes and associated anticipated effect sizes can be used in future trials on adjuncts for peripheral nerve blocks to increase methodological homogeneity.

Analysis of the Use of Sample Size and Effect Size Calculations in a Temporomandibular Disorders Randomised Controlled Trial-Short Narrative Review

BACKGROUND/OBJECTIVES

Temporomandibular disorder (TMD) is the term used to describe a pathology (dysfunction and pain) in the masticatory muscles and temporomandibular joint (TMJ). There is an apparent upward trend in the publication of dental research and a need to continually improve the quality of research. Therefore, this study was conducted to analyse the use of sample size and effect size calculations in a TMD randomised controlled trial.

METHODS

The period was restricted to the full 5 years, i.e., papers published in 2019, 2020, 2021, 2022, and 2023. The filter article type-"Randomized Controlled Trial" was used. The studies were graded on a two-level scale: 0-1. In the case of 1, sample size (SS) and effect size (ES) were calculated.

RESULTS

In the entire study sample, SS was used in 58% of studies, while ES was used in 15% of studies.

CONCLUSIONS

Quality should improve as research increases. One factor that influences quality is the level of statistics. SS and ES calculations provide a basis for understanding the results obtained by the authors. Access to formulas, online calculators and software facilitates these analyses. High-quality trials provide a solid foundation for medical progress, fostering the development of personalized therapies that provide more precise and effective treatment and increase patients' chances of recovery. Improving the quality of TMD research, and medical research in general, helps to increase public confidence in medical advances and raises the standard of patient care.

Reliability and Validity of the Turkish Translation of the PedsQL™ 3.0 Neuromuscular Module for 2-to 4-Year-Olds in Spinal Muscular Atrophy

BACKGROUND

 The Pediatric Quality of Life Inventory™ (PedsQL™) Neuromuscular Module (PedsQL™ 3.0 NM) evaluates the health-related quality of life in children who are affected by neuromuscular diseases. This study's aim is to assess the adaptation of the PedsQL™ 3.0 NM Turkish version (PedsQL™ 3.0 NM-TR) for 2- to 4-year-olds in spinal muscular atrophy (SMA).

METHODS

 The procedure of translating the PedsQL™ 3.0 NM into Turkish was conducted in accordance with the translation methodology outlined by the PedsQL™ measurement model. The PedsQL™ 3.0 NM-TR was administered to 54 parents of children with SMA aged 2 to 4 years. The test-retest reliability and intraclass correlation coefficient (ICC) were measured for reliability analysis. Cronbach's α coefficient and item score correlations were calculated for internal consistency. Concurrent construct validity was evaluated by Pearson correlations between the outcomes of the PedsQL™ 4.0 Generic Core Scale (PedsQL™ 4.0 GCS) and the PedsQL™ 3.0 NM.

RESULTS

 The PedsQL™ 3.0 NM-TR total score shows excellent reliability. The Cronbach's α values for the PedsQL™ 3.0 NM ranged between 0.871 and 0.906, while those for the PedsQL™ 4.0 GCS ranged between 0.843 and 0.897. Test-retest ICC values for the PedsQL™ 3.0 NM-TR ranged between 0.812 and 0.917, and for the PedsQL™ 4.0 GCS ranged between 0.773 and 0.899. The relationship between the PedsQL™ 3.0 NM-TR and the subscores of the PedsQL™ 4.0 GCS demonstrated a range of correlations from excellent to fair, indicating the interplay between two scales.

CONCLUSION

 This study established the PedsQL™ 3.0 NM-TR as reliable, valid, and feasible for use in children aged 2 to 4 years with SMA.

Effectiveness of a Teach-Back Education Program on Perioperative Pain in Patients With Lung Cancer: An Intervention Study Using Behavior Change Wheel

OBJECTIVE

To assess the effect of a teach-back educational intervention using Behavior Change Wheel (BCW) framework on perioperative pain among patients with lung cancer.

METHODS

A prospective quasi-experimental study was conducted in 88 patients with lung cancer from a tertiary hospital in China. According to the order of admission, they were allocated to either control group or intervention group, with 44 patients in each group. Patients in the control group received routine nursing care, while patients in the intervention group were given a teach-back education program based on BCW framework. The visual analog scale (VAS) was adopted to evaluate patients' pain on the day of surgery (T0), 1 (T1), 2 (T2), and 3 (T3) days after surgery. We also recorded the use of patient-controlled analgesia (PCA), the length of hospital stay, and the degree of patients' satisfaction.

RESULTS

Rest pain, pain when coughing, and pain during activity that patients in the intervention group experienced were significantly less severe than those in the control group on T0 and T1. The pain when coughing in the intervention group was also significantly milder on T2 and T3. In addition, the number of self-control time, use duration, and total dose of PCA were significantly lower in the intervention group. Moreover, patients' satisfaction of nursing service was significantly higher in the intervention group.

CONCLUSION

A teach-back education program based on BCW framework was effective in pain management among the perioperative patients with lung cancer. This study demonstrates the application of teach-back method and the BCW in the development of patient education intervention to mitigate perioperative pain.

Evaluation of urinary trace element levels in patients with opioid use disorder undergoing methadone treatment in western Iran

The monitoring of essential and toxic elements in patients with Opioid Use Disorder (OUD) undergoing methadone treatment (MT) is important, and there is limited previous research on the urinary levels of these elements in MT patients. Therefore, the present study aimed to analyze certain elements in the context of methadone treatment compared to a healthy group. In this study, patients with opioid use disorder undergoing MT (n = 67) were compared with a healthy group of companions (n = 62) in terms of urinary concentrations of some essential elements (selenium (Se), zinc (Zn), copper (Cu), iron (Fe), manganese (Mn), calcium (Ca)) and toxic elements (lead (Pb), cadmium (Cd), arsenic (As), and chromium (Cr)). Urine samples were prepared using the acid digestion method with a mixture of nitric acid and perchloric acid and assessed using the ICP-MS method. Our results showed that the two groups had no significant differences in terms of gender, education level, occupation, and smoking status. Urinary concentrations of Se, Cu, and Fe levels were significantly lower in the MT group compared to the healthy subjects. However, the concentrations of Pb, Cd, As, Mn, Cr, and Ca in the MT group were higher than in the healthy group (p < 0.05). No significant difference was established between the levels of Zn in the two groups (p = 0.232). The results of regression analysis revealed that the differences between the concentration levels of all metals (except Zn) between two groups were still remained significant after adjusting for all variables (p < 0.05). The data obtained in the current study showed lower urinary concentrations of some essential elements and higher levels of some toxic elements in the MT group compared to the healthy subjects. These findings should be incorporated into harm-reduction interventions.

A randomised clinical trial study assessing the efficacy of 5% losartan potassium loaded in ethosomal gel to treat human keloids: a trial protocol

BACKGROUND

Keloid is a skin disorder that results from excessive fibrous tissue growth in the area of the initial trauma. Treating keloids can be challenging since the success of various treatments varies from one study to another. Triamcinolone acetonide injection, a standard treatment, can cause undesirable side effects. Meanwhile, the effectiveness of existing topical therapies for keloids is not always reliable. The pro-inflammatory, pro-proliferative, and pro-fibrotic effects of angiotensin II in human skin contribute to keloid formation. Losartan potassium, an angiotensin II blocker, has the potential to act as an anti-keloid agent. Due to the thicker skin structure of a keloid and ease of application, ethosome gel is chosen as a safe and comfortable carrier for losartan potassium, making it a good choice for treating keloids.

METHODS

In this randomised clinical trial, 46 adults with keloids were divided into two treatment groups. One group of 23 participants received 5% losartan potassium loaded in ethosomal gel, while the other group of 23 participants received intralesional injections of 10% triamcinolone acetonide. Over 12 weeks, changes in POSAS 3.0 scores, degree of erythema and pigmentation, surface area, thickness, and pliability of the keloids will be measured at four different times: baseline, 4 weeks, 8 weeks, and 12 weeks. Statistical analysis will be conducted using SPSS software version 24, with a significance level of p < 0.05.

DISCUSSION

Losartan potassium is believed to be beneficial for keloid management because it inhibits the angiotensin II receptor, which plays a role in inflammation, proliferation, and fibrosis. This study examines the efficacy of 5% losartan potassium loaded in ethosomal gel for human keloids.

TRIAL REGISTRATION

Clinicaltrial.gov identifier NCT05893108 . Registered on 7 June 2023.

The Moderating Role of HIV Stigma on the Relationship between Perceived Social Support and Antiretroviral Therapy Adherence Self-Efficacy among Adult PLHIV in South Africa

BACKGROUND

People living with human immune deficiency virus (PLHIV) grapple with distinct challenges, including HIV stigma which affects their antiretroviral therapy (ART) adherence self-efficacy. This study investigates the interaction of HIV stigma and perceived social support on ART adherence self-efficacy among adult PLHIV in South Africa.

METHODS

This study utilized a cross-sectional design that involved 201 participants selected using time location sampling at a tertiary health facility in Durban.

RESULTS

HIV stigma was significantly and negatively associated with self-efficacy (β = -7.860, t = -4.654, p = .001), with variations across different stigma levels (β = -5.844, t = -4.003, p = .001). Social support was significantly and positively associated with self-efficacy at lower HIV stigma levels (β = 7.440, t = 3.887, p = .001), in contrast to higher levels (β = -2.825, t = 1.400, p = .163).

CONCLUSION

Social support significantly influences ART adherence self-efficacy, particularly at lower levels of HIV stigma, but the effect of support weakens as stigma intensifies.

Anisodamine hydrobromide in the treatment of critically ill patients with septic shock: a multicenter randomized controlled trial

BACKGROUND

Septic shock is the development of sepsis to refractory circulatory collapse and metabolic derangements, characterized by persistent hypotension and increased lactate levels. Anisodamine hydrobromide (Ani HBr) is a Chinese medicine used to improve blood flow in circulatory disorders. The purpose of this study was to determine the therapeutic efficacy of Ani HBr in the treatment of patients with septic shock.

METHODS

This was a prospective, multicenter, randomized controlled trial focusing on patients with septic shock in 16 hospitals in China. Patients were randomly assigned in a 1:1 ratio to either the treatment group or the control group. The primary endpoint was 28-day mortality. The secondary outcomes included 7-day mortality, hospital mortality, hospital length of stay, vasopressor-free days within 7 days, etc. These indicators were measured and collected at 0, 6h, 24h, 48h, 72h and 7d after the diagnosis.

RESULTS

Between September 2017 and March 2021, 404 subjects were enrolled. 203 subjects received Ani HBr and 201 subjects were assigned to the control group. The treated group showed lower 28-day mortality than the control group. Stratified analysis further showed significant differences in 28-day mortality between the two groups for patients with a high level of illness severity. We also observed significant differences in 7-day mortality, hospital mortality and some other clinical indicators between the two groups.

CONCLUSION

Ani HBr might be an important adjuvant to conventional treatment to reduce 28-day mortality in patients with septic shock. A large-scale prospective randomized multicenter trial is warranted to confirm our results.

Online anatomy education during the Covid-19 pandemic: Opinions of medical, speech therapy, and BSc Anatomy students

With the emergence of the Covid-19 pandemic in 2020, it was difficult to predict if the "cadaveric-based (golden) standard" of teaching anatomy would be possible in the unforeseeable future. This forced traditional anatomical teaching and learning practices to be transitioned to remote online platforms. This study explored the opinions of anatomy students (n = 51), on their online learning experience of anatomy during the Covid-19 pandemic. A mixed methods approach using a descriptive, exploratory study design was conducted, by use of an online survey. The survey consisted of a six-point Likert scale and was assembled into four sub-categories. Likert scale options ranged from; strongly disagree, to strongly agree, and not applicable. Results obtained seem to tally with expectations, indicating an adequate theoretical course component with room to improve practical online teaching. Most participants had a positive perception of the theoretical course content, duration, and platforms of communication. Virtual classes were simple to navigate with few technical difficulties experienced by the participants. Students also noted having access to sufficient study material, videos, and additional online material. Overall, more than half of all participants reported adapting well to the remote learning environment, however, the greatest challenge experienced highlighted a sense of deprivation from the lack of cadaver exposure and hands-on instruction. This research highlighted the effects of the pandemic on the modality of anatomy education and how it affected students. Although anatomy is multi-modal, it can be concluded that it is possible to achieve academic success by using online learning methods.

Estimation of minimal detectable change in the 10-meter walking test for patients with stroke: a study stratified by gait speed

Objective

This study aimed to classify and calculate the minimal detectable changes (MDC) in gait time and gait speed in a 10-meter walking test (10MWT) in patients with stroke classified according to their gait speed.

Methods

The participants were 84 patients with stroke. Their gait times were measured twice each at their comfortable gait speed (CGS) and maximum gait speed (MGS) on a 10-meter straight track, and gait speed was calculated using gait time. Participants were assigned to three speed groups based on their CGS: low-speed (<0.4 m/s; n = 19); moderate-speed (0.4-0.8 m/s; n = 29); and high-speed (>0.8 m/s; n = 36). For each group, first and second retest reliability and MDC of CGS and MGS were calculated using gait time and gait speed in the 10MWT.

Results

MDCs in the 10MWT at CGS were: low-speed group, gait time 5.25 s, gait speed 0.05 m/s; moderate-speed group, gait time 2.83 s, gait speed 0.11 m/s; and high-speed group, gait time 1.58 s, gait speed 0.21 m/s. MDCs in the 10MWT at MGS were: low-speed group, gait time 7.26 s, gait speed 0.04 m/s; moderate-speed group, gait time 2.48 s, gait speed 0.12 m/s; and high-speed group, gait time 1.28 s, gait speed 0.19 m/s.

Conclusion

Since the MDC of gait speed and gait time differ depending on the participant's gait speed, it is necessary to interpret the results according to the participant's gait speed when judging the effectiveness of therapeutic interventions.

Outcomes of a QST Protocol in Healthy Subjects and Chronic Pain Patients: A Controlled Clinical Trial

Chronic pain is an important cause of disability with a high burden to society. Quantitative sensory testing (QST) is a noninvasive multimodal method used to discriminate the function of nerve fibers. The aim of this study is to propose a new, reproducible, and less time-consuming thermal QST protocol to help characterize and monitor pain. Additionally, this study also compared QST outcomes between healthy and chronic pain subjects. Forty healthy young/adult medical students and fifty adult/elderly chronic pain patients were evaluated in individual sessions including pain history, followed by QST assessments divided into three proposed tests: pain threshold, suprathreshold, and tonic pain. In the chronic pain group, a significantly higher pain threshold (hypoesthesia) and a higher pain sensibility (hyperalgesia) were demonstrated at threshold temperature when compared to healthy participants. The sensitivity to the suprathreshold and tonic stimulus did not prove to be significantly different between both groups. The main results demonstrated that the heat threshold QST tests can be helpful in evaluating hypoesthesia and that the sensitivity threshold temperature test can demonstrate hyperalgesia in individuals with chronic pain. In conclusion, this study demonstrates the importance of using tools such as QST as a complement to detect changes in several pain dimensions.

The Symptom Characteristics and the Efficacy of Combining Therapies in Inpatients with Atopic Dermatitis: A Study on Vietnamese Population

Background:  Currently, biologics and targeted disease-modifying therapies were developed to provide an effective control for adult with moderate-to-severe atopic dermatitis. This study aimed to describe clinical features, stages, and severity levels of the disease as well as to evaluate the therapeutic efficacy of the combining therapies in adults with atopic dermatitis. Methods: 128 patients with atopic dermatitis diagnosis based on the Rajka and Hanifi standards at the Inpatient Department of Can Tho Dermato-Venereology Hospital from May 2018 to May 2020 were recruited in this study. The clinical characteristics were recorded. The treatment response was evaluated through the improvement of clinical presentations and the altering SCORAD score.   Results: The study showed that people aged 60 and over made up the largest proportion of total investigated patients. Pruritus was the predominant symptom of atopic dermatitis. There was an association between xerosis symptom and disease severity. After two weeks of treatment, the mean of SCORAD score significantly decreased by more than halved. Additionally, 88.4% of patients showed an excellent response and there was no patient with non/poor improvement. Conclusions: Our study supports that the combination of therapeutic methods might reduce symptoms in atopic dermatitis patients, and thereby improving their quality of life.

Web-Based Personalized Intervention to Improve Quality of Life and Self-Efficacy of Long-Term Breast Cancer Survivors: Study Protocol for a Randomized Controlled Trial

Long-term breast cancer survivors (>5 years free of disease) may suffer late sequelae of cancer that impact on their quality of life. The use of telehealth for cancer care is recommended but little is known about the effectiveness of digital interventions for long-term cancer survivors. This study aims to evaluate the effectiveness of a web-based personalized intervention based on artificial intelligence instead of usual primary health care to improve the quality of life of long-term survivors of breast cancer and self-efficacy for the management of late sequelae. A randomized controlled trial will be conducted. The sample will consist of long-term breast cancer survivors recruited from primary health centers. Women will be randomly assigned to the intervention group to receive a web-based personalized intervention or to the control group to receive standard primary health care by nurses. Data on quality of life of cancer survivors and self-efficacy for the management of late sequelae of cancer will be collected and assessed at preintervention, and at 3, 6, and 9 months. It is expected that, at the end of the programme, the experimental group will have improved quality of life and improved self-efficacy for the management of late sequelae of cancer.

A practical solution to estimate the sample size required for clinical prediction models generated from observational research on data

Background

Estimating the required sample size is crucial when developing and validating clinical prediction models. However, there is no consensus about how to determine the sample size in such a setting. Here, the goal was to compare available methods to define a practical solution to sample size estimation for clinical predictive models, as applied to Horizon 2020 PRIMAGE as a case study.

Methods

Three different methods (Riley’s; “rule of thumb” with 10 and 5 events per predictor) were employed to calculate the sample size required to develop predictive models to analyse the variation in sample size as a function of different parameters. Subsequently, the sample size for model validation was also estimated.

Results

To develop reliable predictive models, 1397 neuroblastoma patients are required, 1060 high-risk neuroblastoma patients and 1345 diffuse intrinsic pontine glioma (DIPG) patients. This sample size can be lowered by reducing the number of variables included in the model, by including direct measures of the outcome to be predicted and/or by increasing the follow-up period. For model validation, the estimated sample size resulted to be 326 patients for neuroblastoma, 246 for high-risk neuroblastoma, and 592 for DIPG.

Conclusions

Given the variability of the different sample sizes obtained, we recommend using methods based on epidemiological data and the nature of the results, as the results are tailored to the specific clinical problem. In addition, sample size can be reduced by lowering the number of parameter predictors, by including direct measures of the outcome of interest.

Artificial intelligence in Emergency Medical Services dispatching: assessing the potential impact of an automatic speech recognition software on stroke detection taking the Capital Region of Denmark as case in point

BACKGROUND AND PURPOSE

Stroke recognition at the Emergency Medical Services (EMS) impacts the stroke treatment and thus the related health outcome. At the EMS Copenhagen 66.2% of strokes are detected by the Emergency Medical Dispatcher (EMD) and in Denmark approximately 50% of stroke patients arrive at the hospital within the time-to-treatment. An automatic speech recognition software (ASR) can increase the recognition of Out-of-Hospital cardiac arrest (OHCA) at the EMS by 16%. This research aims to analyse the potential impact an ASR could have on stroke recognition at the EMS Copenhagen and the related treatment.

METHODS

Stroke patient data (n = 9049) from the years 2016-2018 were analysed retrospectively, regarding correlations between stroke detection at the EMS and stroke specific, as well as personal characteristics such as stroke type, sex, age, weekday, time of day, year, EMS number contacted, and treatment. The possible increase in stroke detection through an ASR and the effect on stroke treatment was calculated based on the impact of an existing ASR to detect OHCA from CORTI AI.

RESULTS

The Chi-Square test with the respective post-hoc test identified a negative correlation between stroke detection and females, the 1813-Medical Helpline, as well as weekends, and a positive correlation between stroke detection and treatment and thrombolysis. While the association analysis showed a moderate correlation between stroke detection and treatment the correlation to the other treatment options was weak or very weak. A potential increase in stroke detection to 61.19% with an ASR and hence an increase of thrombolysis by 5% in stroke patients calling within time-to-treatment was predicted.

CONCLUSIONS

An ASR can potentially improve stroke recognition by EMDs and subsequent stroke treatment at the EMS Copenhagen. Based on the analysis results improvement of stroke recognition is particularly relevant for females, younger stroke patients, calls received through the 1813-Medical Helpline, and on weekends.

TRIAL REGISTRATION

This study was registered at the Danish Data Protection Agency (PVH-2014-002) and the Danish Patient Safety Authority (R-21013122).

Comparison of different types of exercise training on resting blood pressure in 30-45 years old adults: a randomised controlled trial

Hypertension is the most metastasizing non-communicable disease, which has affected more than 1.4 billion people, worldwide. Exercise is the core management strategy for hypertensive individuals. Extensive literature is available for each kind of exercise that is isometric hand grip training (IHGT), resistance training (RT), and aerobic training (AT). However, the comparison between these exercise regimens has not been done in a single trial. The trial was conducted on 126 subjects in Hisar, an urban area of Haryana (INDIA), from July 2017 to December 2018. Subjects were randomly assigned to four groups: control (n=33), IHGT (n=32), RT (n=31), and AT (n=30). Study variables were measured at baseline, 2nd week, 4th week, 6th week, and also after the 8th week of intervention. Experimental groups showed significant reduction in all the components of blood pressure in comparison to control group. The RT group showed maximum reduction in blood pressure in comparison to other regimens (systolic blood pressure: RT > IHGT > AT; diastolic blood pressure: RT > AT > IHGT). However, the difference between the groups is not statistically significant (P>0.05). The study findings reveal that different kind of exercise regimens are equally effective in lowering blood pressure among pre hypertensive and stage 1 hypertension adults.

A Pilot Study on the 1H-NMR Serum Metabolic Profile of Takotsubo Patients Reveals Systemic Response to Oxidative Stress

Takotsubo syndrome (TTS) presents as an acute coronary syndrome characterized by severe left ventricular (LV) dysfunction and non-obstructive coronary artery disease that typically shows spontaneous recovery within days or weeks. The mechanisms behind TTS are mainly related to beta-adrenergic overstimulation and acute endogenous catecholamine surge, both of which could increase oxidative status that may induce further deterioration of cardiac function. Although several studies reported evidence of inflammation and oxidative stress overload in myocardial tissue of TTS models, systemic biochemical evidence of augmented oxidant activity in patients with TTS is lacking. In this study, serum samples of ten TTS patients and ten controls have been analyzed using ¹H-NMR spectroscopy. The results of this pilot study show a marked alteration in the systemic metabolic profile of TTS patients, mainly characterized by significant elevation of ketone bodies, 2-hydroxybutyrate, acetyl-L-carnitine, and glutamate levels, in contrast with a decrease of several amino acid levels. The overall metabolic fingerprint reflects a systemic response to oxidative stress caused by the stressor that triggered the syndrome’s onset.

People to policy: The promise and challenges of big data for India

Big data holds great promise to help unravel insights to bridge the gap in human understanding. There has to be an emphasis on the quality of the data points being collected to ensure meaningful analysis. India has made significant strides to lay down a strong framework through the National Digital Health Blueprint and the National Health Stack for the future. There is a need to focus on the first important step of collection of a “good quality” data point through the implementation of electronic medical records by the health care providers. In India, 60 million individuals move below the poverty line every year because of the expenses related to unforeseen illness that adversely affects the individual's welfare and the nation's economic growth. With an out-of-pocket expense rate currently at 70% and the government's health budget at a mere 1.3% of its GDP (gross domestic product), data-driven decisions are the need of the hour for policy making and to ensure equitable, efficient, and excellent delivery of health care. There is a huge potential to harness the power of big data to generate insights to address the four big challenges of health care in India – availability, accessibility, affordability, and acceptability.

Sitagliptin on carotid intima-media thickness in type 2 diabetes and hyperuricemia patients: a subgroup analysis of the PROLOGUE study

Background and Aims:

Studies have shown that dipeptidyl peptidase-4 (DDP-4) inhibitors have anti-atherosclerotic effects. However, in the PROLOGUE study, sitagliptin failed to slow the progression of carotid intima-media thickness (CIMT) relative to conventional therapy. We conducted a post hoc analysis of the PROLOGUE study and compared the effects of sitagliptin and conventional therapy on changes in CIMT in subgroups with or without hyperuricemia.

Methods:

The PROLOGUE study was a randomized controlled trial of 442 patients with type 2 diabetes mellitus (T2DM). Patients were randomized to receive sitagliptin added therapy or conventional therapy. Based on the serum uric acid levels of all study populations in the PROLOGUE study, we divided them into hyperuricemia subgroup (n = 104) and non-hyperuricemia subgroup (n = 331). The primary outcome was changed in carotid intima-media thickness (CIMT) parameters compared with baseline during the 24 months treatment period.

Results:

In the hyperuricemia subgroup, compared with the conventional therapy group, the changes in the mean internal carotid artery (ICA)-IMT and max ICA-IMT at 24 months were significantly lower in the sitagliptin group [−0.233 mm, 95% confidence interval (CI) (−0.419 to 0.046), p = 0.015 and −0.325 mm, 95% CI (−0.583 to −0.068), p = 0.014], although there was no significant difference in the common carotid artery CIMT.

Conclusion:

The results of our analysis indicated that sitagliptin attenuated the progression of CIMT than conventional therapy in T2DM and hyperuricemia patients.

Sample Size Calculation in Medical Research: A Primer

Quality of research is determined by many factors and one such climacteric factor is sample size. Inability to use correct sample size in study might lead to fallacious results in the form of rejection of true findings or approval of false results. Too large sample size is wastage of resources and use of too small sample size might fail to answer the research question or provide imprecise results and may question the validity of study. Despite being such a paramount aspect of research, the knowledge about sample size calculation is sparse among researchers. Why is it important to calculate sample size; when to calculate it; how to calculate it and what details about sample size calculation should be reported in research protocols or articles; are the lesser known basics to majority of researchers. The present review is directed to address these aforementioned fundamentals about sample size. Sample size should be calculated during the initial phase of planning of study. Several components are required for sample size calculation such as effect size, type-1 error, type-2 error, and variance. Researchers must be aware that there are different formulas for calculating sample size for different types of study designs. The researcher must include details about sample size calculation in the methodology section, so that it can be justified and it also adds to the transparency of the study. The literature about calculation of sample size for different study designs is scattered over many textbooks and journals. Scrupulous literature search was conducted to find the passable information for this review. This paper presents the sample size calculation formulas in a single review in a simplified manner with relevant examples, so that researchers may adequately use them in their research.

Minimal clinically important differences in randomised clinical trials on pain management after total hip and knee arthroplasty: a systematic review

BACKGROUND

Sample size determination is essential for reliable hypothesis testing in clinical trials and should rely on adequate sample size calculations with alpha, beta, variance, and an effect size being the minimal clinically important difference (MCID). This facilitates interpretation of the clinical relevance of statistically significant results. No gold standard for MCIDs exists in postoperative pain research.

METHODS

We searched Cochrane Central Register of Controlled Trials, MEDLINE, and Embase for English language articles on randomised trials investigating analgesic interventions after total hip or knee arthroplasty. Primary outcomes were the reported MCIDs for pain score and cumulated rescue opioid consumption. Secondary outcomes included reported sample size calculations and propensity to report statistical significance without reaching MCID. Trend analyses were conducted using statistical process control.

RESULTS

We included 570 trials. Median MCID for 0-24 h opioid consumption was 10 mg i.v. morphine equivalents for absolute reductions (interquartile range [IQR]: 6.8-14.5) and relative 40% (IQR: 30-50%). Median MCIDs for pain scores were absolute 15 mm at rest (IQR: 10-20) and 18 mm during movement (IQR: 10-20) on a 0-100 mm VAS and relative 30% (IQR: 20-30%). No trends were demonstrated for MCIDs. Adequate sample size calculations were reported in 34% of trials. In 46% of trials with statistically significant primary outcomes, the differences did not reach the predetermined MCID.

CONCLUSIONS

We provide clinician-perceived MCID estimates for rescue opioid consumption and pain scores that can be used for sample size calculations until reliable evidence-based patient-rated MCIDs emerge. Nearly half of the trials with significant findings did not reach the predetermined MCID.

Consistency of the Empirical Distributions of Navigation Positioning System Errors with Theoretical Distributions-Comparative Analysis of the DGPS and EGNOS Systems in the Years 2006 and 2014

Positioning systems are used to determine position coordinates in navigation (air, land and marine). The accuracy of an object’s position is described by the position error and a statistical analysis can determine its measures, which usually include: Root Mean Square (RMS), twice the Distance Root Mean Square (2DRMS), Circular Error Probable (CEP) and Spherical Probable Error (SEP). It is commonly assumed in navigation that position errors are random and that their distribution are consistent with the normal distribution. This assumption is based on the popularity of the Gauss distribution in science, the simplicity of calculating RMS values for 68% and 95% probabilities, as well as the intuitive perception of randomness in the statistics which this distribution reflects. It should be noted, however, that the necessary conditions for a random variable to be normally distributed include the independence of measurements and identical conditions of their realisation, which is not the case in the iterative method of determining successive positions, the filtration of coordinates or the dependence of the position error on meteorological conditions. In the preface to this publication, examples are provided which indicate that position errors in some navigation systems may not be consistent with the normal distribution. The subsequent section describes basic statistical tests for assessing the fit between the empirical and theoretical distributions (Anderson-Darling, chi-square and Kolmogorov-Smirnov). Next, statistical tests of the position error distributions of very long Differential Global Positioning System (DGPS) and European Geostationary Navigation Overlay Service (EGNOS) campaigns from different years (2006 and 2014) were performed with the number of measurements per session being 900’000 fixes. In addition, the paper discusses selected statistical distributions that fit the empirical measurement results better than the normal distribution. Research has shown that normal distribution is not the optimal statistical distribution to describe position errors of navigation systems. The distributions that describe navigation positioning system errors more accurately include: beta, gamma, logistic and lognormal distributions.

Statistical Distribution Analysis of Navigation Positioning System Errors-Issue of the Empirical Sample Size

Positioning systems are used to determine position coordinates in navigation (air, land, and marine). Statistical analysis of their accuracy assumes that the position errors (latitude—δ_φ and longitude—δ_λ) are random and that their distributions are consistent with the normal distribution. However, in practice, these errors do not appear in a random way, since the position determination in navigation systems is done with an iterative method. It causes so-called “Position Random Walk”, similar to the term “Random Walk” known from statistics. It results in the empirical distribution of δ_φ and δ_λ being inconsistent with the normal distribution, even for samples of up to several thousand measurements. This phenomenon results in a significant overestimation of the accuracy of position determination calculated from such a short series of measurements, causing these tests to lose their representativeness. This paper attempts to determine the length of a measurement session (number of measurements) that is representative of the positioning system. This will be a measurement session of such a length that the position error statistics (δ_φ and δ_λ) represented by the standard deviation values are close to the real values and the calculated mean values (φ¯ and λ¯) are also close to the real values. Special attention will also be paid to the selection of an appropriate (statistically reliable) number of measurements to be tested statistically to verify the hypothesis that the δ_φ and δ_λ distributions are consistent with the normal distribution. Empirical measurement data are taken from different positioning systems: Global Positioning System (GPS) (168′286 fixes), Differential Global Positioning System (DGPS) (864′000 fixes), European Geostationary Navigation Overlay Service (EGNOS) (928′492 fixes), and Decca Navigator system (4052 fixes). The analyses showed that all researched positioning systems (GPS, DGPS, EGNOS and Decca Navigator) are characterized by the Position Random Walk (PRW), which resulted in that the empirical distribution of δ_φ and δ_λ being inconsistent with the normal distribution. The size of the PRW depends on the nominal accuracy of position determination by the system. It was found that measurement sessions consisting of 1000 fixes (for the GPS system) overestimate the accuracy analysis results by 109.1% and cannot be considered representative. Furthermore, when analyzing the results of long measurement campaigns (GPS and DGPS), it was found that the representative length of the measurement session differs for each positioning system and should be determined for each of them individually.

Association of VEGFA and IL1β gene polymorphisms with preeclampsia in Sudanese women

Background

Preeclampsia can lead to adverse maternal and perinatal outcomes. There are few studies on the genetic factors associated with preeclampsia in Africa in general and in Sudan in specific.

Methods

A case–control study (60 women in each arm) was conducted at Saad Abualila Hospital in Khartoum, Sudan, from March to September 2018. The participants were genotyped for vascular endothelial growth factor A (VEGFA) rs3025039, interleukin 1 beta (IL1β) rs16944, and IL1β rs1143634 by performing polymerase chain reaction–restriction fragment length polymorphism analysis, and the results were confirmed by DNA sequencing.

Results

There was no significant difference in the age, parity, body mass index, or other characteristics tested between the preeclampsia group and the control group (60 women in each arm). The rs3025039, rs16944, and rs1143634 genotypes were distributed in accordance with Hardy–Weinberg equilibrium (p > .05). For rs3025039, CT, CT+TT, and the T allele were risk factors for preeclampsia (odds ratio [OR] = 2.4; 95% CI [1.12–5.32]; p = .02; OR = 2.49 [1.17–25.27]; p = .01; OR = 2.05; 95% CI [1.10–3.83]; p = .02, respectively). Regarding rs16944, only the heterozygous genotype CT was associated with preeclampsia (OR = 2.55; 95% CI [1.15–5.56]; p = .01). Regarding rs1143634, CT, CT+TT, and the T allele were risk factors for preeclampsia (OR = 5.28; 95% CI [2.26–12.33]; p < .001; OR = 4.50; 95% CI [2.06–9.81]; p < .001; OR = 2.75; 95% CI [1.48–5.12]; p = .001, respectively).

Conclusion

Polymorphisms in IL1β and VEGFA were associated with preeclampsia in this setting. Significant associations were observed between preeclampsia and rs3025039, rs16944, and rs1143634.

Association between odontoma size, age and gender: Multivariate analysis of retrospective data

Background

The variety of characteristics related to odontoma research, including an unexplored one such as size, merits a multivariate approach that allows the adequate drawing of inferences with pertinent conclusions. The objective of this study is to establish the possible association between some characteristics related to the odontoma, tumor size among them.

Material and Methods

The sociodemographic characteristics of 60 patients were evaluated. Diagnosis, size, location, type of treatment performed, and prognosis were determined. These data were analyzed descriptively and through multivariate models.

Results

Thirty-four compound and 26 complex odontomas in 32 men and 28 women were observed. The age average of patients was 15.6±11 years. Most of the odontomas presented a size inferior to 10 mm. A statistically significant association was observed between the routine radiographic finding and the absence of dental eruption (p=0.0001). The model of linear regression adjusted between odontoma size and age (β=0.321, p=0.01), as well as the model of logistic regression adjusted between gender (men) and tumor size (OR=12; 1.7 - 93 IC 95%, (p=0.01) were statistically significant.

Conclusions

Statistically significant associations between odontoma size and age, and between the male gender and odontomas smaller than 10 mm were found adjusting by other confounding variables. These results could grant clinicians a greater knowledge of the context of odontoma characteristics, which in turn could favor a better diagnostic and therapeutic decision-making.

Key words:Odontoma, compound odontoma, diagnosis, multivariate analysis.

Separating forensic, WWII, and archaeological human skeletal remains using ATR-FTIR spectra

ATR-FTIR spectroscopy is a fast and accessible, minimally or non-destructive technique which provides information on physiochemical characteristics of analyzed materials. In forensic and archaeological sciences, it is commonly used for answering numerous questions, including the archaeological or forensic context of the human skeletal remains. In this research, the accuracy of ATR-FTIR-obtained spectra for separation between forensic, WWII, and archaeological human skeletal remains was investigated. Building from the previously proposed methodological procedures, various ratio-based and whole spectra separation procedures were applied, carefully analyzed, and evaluated. Results showed that employing whole spectral domains works best for the separation of archaeological, WWII, and forensic samples, even with samples of highly variable origin. Principal component analysis (PCA) further highlighted the necessity of acknowledging all the major components in the remains: amides, phosphates, and carbonates for the separation. Most influential proved to be amide I, namely its secondary structure, which presented well-preserved and organized collagen structure in forensic and WWII samples, while highly degraded in archaeological samples. Using the whole spectral domain for separation between samples from different contexts proved to be fast and simple, with no manipulation beyond baseline correction and normalization of spectra necessary. However, a dataset with samples of known origin is required for the learning model and predictions. A less accurate alternative is separation based on combining ratios of peaks correlating to organics and minerals in the bone, which eliminated overlapping and managed to classify the majority of the samples correctly as archaeological, WWII, or forensic.

Effectiveness of dry needling on the local pressure pain threshold in patients with masticatory myofascial pain. Systematic review and preliminary clinical trial

Objective: To systematically review the literature to identify controlled clinical trials evaluating the effectiveness of deep dry needling (DDN) in the treatment of patients with chronic masticatory myofascial pain (MMP).Methods: The sample size for a clinical trial was calculated and involved five patients who consecutively presented for treatment of MMP. The percentage of change in the means of three consecutive measurements of the pressure pain threshold (PPT) of myofascial trigger points (MTPs) was calculated and the statistical significance of this difference evaluated using the Wilcoxon test.Results: Twenty-five studies were considered for inclusion based on title and abstract. Only 2 studies met the inclusion criteria and were used to calculate the sample size. DDN significantly increased (p = 0.04) the PPT in MTP (44.6%) compared with sham procedure (-5.5%).Conclusion: Patients with chronic MMP treated with DDN of MTPs showed an increase in PPT measurements on the experimental side.Abbreviations: CGRP: calcitonin gene-related peptide; DC/TMD: diagnostic criteria for temporomandibular disorders; DDN: deep dry needling; DN: dry needling; LILACS: Latin American and Caribbean Health Sciences; MMP: masticatory myofascial pain; MTP: myofascial trigger point; MTPs: myofascial trigger points; PPT: pressure pain threshold; RCTs: randomized clinical trials; SciELO: Scientific Electronic Library Online; SP: Substance P; TMD: temporomandibular disorders.

Factor-V Leiden G1691A and prothrombin G20210A polymorphisms in Sudanese women with preeclampsia, a case -control study

Background

Preeclampsia can lead to adverse maternal and perinatal outcomes. There are few studies on the association of preeclampsia with thrombophilia in Africa including Sudan.

Methods

A case –controls study was conducted at Saad Abualila Hospital in Khartoum, Sudan during the period of February through November 2017. The cases were women with preeclampsia and healthy pregnant women were the controls (180 women in each arm of the study). Genotyping for Factor-V Leiden 1691G/A and Prothrombin gene variation 20210G/A was done by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP).

Results

There was no significant difference in the age, parity, body mass index (BMI) and the other characteristics between the cases and the controls. Genotypes distribution of Factor V Leiden 1691G/A and prothrombin gene 20210G/A in controls was in accordance with the Hardy–Weinberg equilibrium (P > 0.05). The factor V Leiden-variation was present in 9.6% of the cases compared with 0.6% of the controls, P < 0.001 (OR = 18.60, 95% CI = 2.38–136.1). Only 4 patients with severe preeclampsia had homozygous variation A/A and it was not detected in the controls. Prothrombin G20210A variations not detected neither in the cases nor in the controls group.

Conclusions

High prevalence of Factor V Leiden 1691G/A variation in preeclamptic patients compared to controls suggest an involvement of this variation in predisposing to preeclampsia in this setting.

Clinical assessment of Eustachian tube dysfunction through the Eustachian tube dysfunction questionnaire (ETDQ-7) and tubomanometry

OBJECTIVE

Evaluation of the severity of Eustachian tube dysfunction using the Spanish validation of the Eustachian Tube Dysfunction Questionnaire-7 (ETDQ-7) and tubomanometry (TMM).

MATERIALS AND METHODS

Spanish validation of the ETDQ-7.

PATIENTS

Prospective study with 125 patients, 75 of whom reported symptoms compatible with Eustachian tube dysfunction.

OUTCOME MEASURES

The Spanish version of the ETDQ-7 was administered after translation and back-translation. Internal consistency and reliability were established. Usefulness evaluation of TMM plus ETDQ-7 in the study of Eustachian tube dysfunction.

RESULTS

The Spanish adaptation of the ETDQ-7 showed high reliability and internal consistency. TMM and ETDQ-7 together showed increased sensitivity and specificity in the diagnosis of Eustachian tube dysfunction.

CONCLUSIONS

The Spanish adaptation of the ETDQ-7 is valid, reliable and can be used in a clinical setting to quantify the impact and severity of chronic dysfunction on patients' lives. A new test formed by combining ETDQ-7 and TMM could be a routine test in the diagnosis of Eustachian tube dysfunction.

Nasally-Administered Oxytocin Has Limited Effects on Owner-Directed Attachment Behavior in Pet Dogs (Canis lupus familiaris)

The present study explored the effects of intranasal oxytocin, a naturally occurring hormone, on the behavior of pet dogs during an attachment test. Each dog participated in two testing sessions. On one visit saline was administered nasally, and on another, oxytocin was administered nasally. For half of the dogs (n = 20), solutions were administered with a Mucosal Atomization Device (MAD) and for half of the dogs (n = 20), solutions were administered using a nasal spray bottle. Condition order was counterbalanced and a double-blind methodology was employed. Following a 30-min wait period after administration of solutions, dog-owner pairs participated in the Secure Base Test, a short attachment test consisting of three 2-min phases: (1) Baseline- the owner was present, dogs were able to freely explore the testing room (2) Alone- dogs were left alone in the testing room (3) Return- owners re-entered the room and were reunited with their dog. In each phase the dog was evaluated for contact seeking, exploration, and avoidance behaviors. Although, oxytocin administration was expected to increase owner-directed proximity and contact seeking behavior, this effect was not observed. In fact, in the baseline phase, dogs spent significantly more time seeking the proximity of their owners when they received saline than when they received OT (p < 0.05). Sex differences were also assessed for the behavioral variables of interest in the Secure Base Test, and results indicated that OT did not affect dogs' behavior in the alone phase, but when saline was administered, females spent significantly more time in contact with the door than males in the alone phase (p < 0.05). Overall, the effects of nasally administered oxytocin on attachment related behavior appeared to be limited or inconsistent for this pet dog population.

Basic statistical tools in research and data analysis

Statistical methods involved in carrying out a study include planning, designing, collecting data, analysing, drawing meaningful interpretation and reporting of the research findings. The statistical analysis gives meaning to the meaningless numbers, thereby breathing life into a lifeless data. The results and inferences are precise only if proper statistical tests are used. This article will try to acquaint the reader with the basic research tools that are utilised while conducting various studies. The article covers a brief outline of the variables, an understanding of quantitative and qualitative variables and the measures of central tendency. An idea of the sample size estimation, power analysis and the statistical errors is given. Finally, there is a summary of parametric and non-parametric tests used for data analysis.