Sample size and power for a stratified doubly randomized preference design

2016 ◽  
Vol 27 (7) ◽  
pp. 2168-2184 ◽  
Author(s):  
Briana Cameron ◽  
Denise A Esserman
Keyword(s):  
Sample Size ◽  
Trial Design ◽  
Treatment Preference ◽  
Patient Treatment ◽  
Efficient Design ◽  
Two Stage ◽  
Entire Study ◽  
Number Of Patients ◽  
Study Population

The two-stage (or doubly) randomized preference trial design is an important tool for researchers seeking to disentangle the role of patient treatment preference on treatment response through estimation of selection and preference effects. Up until now, these designs have been limited by their assumption of equal preference rates and effect sizes across the entire study population. We propose a stratified two-stage randomized trial design that addresses this limitation. We begin by deriving stratified test statistics for the treatment, preference, and selection effects. Next, we develop a sample size formula for the number of patients required to detect each effect. The properties of the model and the efficiency of the design are established using a series of simulation studies. We demonstrate the applicability of the design using a study of Hepatitis C treatment modality, specialty clinic versus mobile medical clinic. In this example, a stratified preference design (stratified by alcohol/drug use) may more closely capture the true distribution of patient preferences and allow for a more efficient design than a design which ignores these differences (unstratified version).

scholarly journals CLINICAL PHARMACIST-LED PROGRAM ON MEDICATION RECONCILIATION AND PATIENT COUNSELING IN THE DEPARTMENT OF GASTROENTEROLOGY

2019 ◽  
pp. 6-10
Author(s):  
U. KRUTHIKA ◽  
M. SUDHASREE ◽  
J. MOUNIKA ◽  
N. TANDAVA KRISHNA ◽  
M. DIVYA ◽  
...  
Keyword(s):  
Patient Safety ◽  
Sample Size ◽  
Clinical Pharmacist ◽  
Medication Reconciliation ◽  
Patient Counseling ◽  
Interventional Study ◽  
Total Prevalence ◽  
Study Population ◽  
Male Patients

Objective: To study the effects of medication reconciliation and patient counseling on the overall health benefits of the patients in the department of gastroenterology. Methods: This study is a prospective interventional study, was conducted in a 500 bedded MNR Hospital. The sample size taken was 150 patients and the study population comprised of patients aged 18-80 y, admitted in the hospital during the study period of six months. Results: Out of 150 patients, there were 98 (65.33%) male patients and 52 (34.67%) female patients. Patients between 18 and 30 y of age were 29(19.33%), between the age of 30 and 50 y were 71 (47.33%) and above 50 were 50(33.33%). Pancreatitis was most prevalent with 21% of total prevalence, followed by CLD and cholelithiasis with 17%, then IBD 16%, PUD and Gastritis 5%, GERD 4% and other diseases 15%. Conclusion: The basic role of the pharmacist, is to help in minimizing the errors and to perform medication reconciliation. In patient counseling, pharmacists provide information about the disease, and the medications to increase patient safety and the changes in the behavior for the better outcome.

scholarly journals Cost-efficient designs for three-arm trials with treatment delivered by health professionals: Sample sizes for a combination of nested and crossed designs

2018 ◽  
Vol 15 (2) ◽  
pp. 169-177 ◽  
Author(s):  
Mirjam Moerbeek
Keyword(s):  
Health Professional ◽  
Sample Size ◽  
Health Professionals ◽  
Pairwise Comparison ◽  
Efficient Design ◽  
Sample Sizes ◽  
Treatment Conditions ◽  
Mathematical Expressions ◽  
Number Of Patients ◽  
Cost Efficient

Background This article studies the design of trials that compare three treatment conditions that are delivered by two types of health professionals. The one type of health professional delivers one treatment, and the other type delivers two treatments, hence, this design is a combination of a nested and crossed design. As each health professional treats multiple patients, the data have a nested structure. This nested structure has thus far been ignored in the design of such trials, which may result in an underestimate of the required sample size. In the design stage, the sample sizes should be determined such that a desired power is achieved for each of the three pairwise comparisons, while keeping costs or sample size at a minimum. Methods The statistical model that relates outcome to treatment condition and explicitly takes the nested data structure into account is presented. Mathematical expressions that relate sample size to power are derived for each of the three pairwise comparisons on the basis of this model. The cost-efficient design achieves sufficient power for each pairwise comparison at lowest costs. Alternatively, one may minimize the total number of patients. The sample sizes are found numerically and an Internet application is available for this purpose. The design is also compared to a nested design in which each health professional delivers just one treatment. Results Mathematical expressions show that this design is more efficient than the nested design. For each pairwise comparison, power increases with the number of health professionals and the number of patients per health professional. The methodology of finding a cost-efficient design is illustrated using a trial that compares treatments for social phobia. The optimal sample sizes reflect the costs for training and supervising psychologists and psychiatrists, and the patient-level costs in the three treatment conditions. Conclusion This article provides the methodology for designing trials that compare three treatment conditions while taking the nesting of patients within health professionals into account. As such, it helps to avoid underpowered trials. To use the methodology, a priori estimates of the total outcome variances and intraclass correlation coefficients must be obtained from experts’ opinions or findings in the literature.

scholarly journals The role of field education officials in the acquisition of teachers of the competencies of teaching science from the viewpoint of students trained in the Faculty of Education; in Shaqra University in Afif: دور مسؤولي التربية الميدانية في اكتساب الطلبة المعلمين لكفايات تدريس العلوم من وجهة نظر الطلبة المتدربين بكلية التربية؛ في جامعة شقراء بعفيف

2019 ◽  
Vol 3 (27) ◽  
Author(s):  
Daidan Nasser Al-Otaibi
Keyword(s):  
Student Teachers ◽  
Science Teachers ◽  
School Principal ◽  
Field Education ◽  
Joint Work ◽  
Entire Study ◽  
Study Population ◽  
General Average ◽  
Faculty Of Education

The study aimed to identify the role of field education officials (college supervisor, school principal, and collaborating teacher) - the importance and practice of - in students ’teachers acquiring the necessary competencies to teach science. And to identify the problems facing students, from the viewpoint of student teachers in the disciplines of natural sciences, at the Faculty of Education at Shaqra University in Afif, and to achieve the goals of the study, the researcher used the descriptive approach; the tool was a questionnaire that was applied to the entire study population, which was (60) students. The results showed the following: The overall role obtained a total average of (3.36 out of 5) with an important / high verbal grade, and at the level of the two main aspects, the importance aspect obtained a general average (3.43) with a verbal grade (very important), while the degree of practice aspect got an average (3.28) with a grade of (high) and at the level of fields; the practices of the school principals were the most important among field education officials, and the college supervisor was the best practicing of his roles. And that the most important problems facing the student teacher with regard to the college supervisor is the lack of attendance of the classes that the student performs in the school of application. Based on the results of the study, the researcher presented a set of recommendations, including: the necessity of identifying the largest possible number of distinguished schools for field training for students in science teachers; coordination and joint work to clarify the roles of each authority related to field education; and finding appropriate solutions to the problems facing students / teachers. The researcher has suggested a number of studies that can contribute to the advancement of field education in science education.

The Role of the Acute Octreotide Suppression Test in Detecting Patients with Neuroendocrine Neoplasms

2018 ◽  
Vol 107 (3) ◽  
pp. 284-291
Author(s):  
Ivan Kruljac ◽  
Ivan Vičić ◽  
Kristina Blaslov ◽  
Zorica Kolak ◽  
Martina Benković ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Chromogranin A ◽  
Elevated Serum ◽  
Neuroendocrine Neoplasms ◽  
Baseline Serum ◽  
Entire Study ◽  
Promising Tool ◽  
Study Population ◽  
Suppression Test

Background: Serum chromogranin A (CgA) is routinely used as a biomarker in patients with neuroendocrine neoplasms (NENs). Several conditions and comorbidities may be associated with falsely elevated CgA, often leading to extensive diagnostic evaluation, which may be costly and harmful. The aim of this study was to analyze the effectiveness of the acute octreotide suppression test (AOST) in differentiating falsely elevated serum CgA. Methods: Our prospective study enrolled 45 patients from two different patient cohorts: (1) 29 patients with suspicion or presence of NENs (extensive workup and subsequent biopsy confirmed 16 NENs); (2) 16 consecutive patients admitted via the Emergency Department without NENs (non-NENs). AOST was performed after an overnight fast. Baseline CgA was measured, after which 0.25 mg of octreotide was administered subcutaneously. CgA was measured 3 and 6 h after administration. Results: Baseline CgA levels were similar in NENs and non-NENs. At the end of the AOST, CgA decreased by a median of 83.3% (41.0–127.4) in non-NENs and 13.8% (0.0–43.6) in NENs (p < 0.001). In patients with increased baseline CgA, a decrease in CgA at the 6th hour of < 51.3% had 90.0% sensitivity and 88.9% specificity in detecting NENs. In patients with normal baseline serum CgA, a decrease in CgA at the 3rd hour of < 17.6% had 83.3% sensitivity and 81.8% specificity in detecting patients with NENs. The diagnostic accuracy of the AOST in the entire study population was 86.7%. Conclusions: AOST is a promising tool to increase the diagnostic accuracy of serum CgA.

Two‐stage randomized trial design for testing treatment, preference, and self‐selection effects for count outcomes

2020 ◽  
Vol 39 (25) ◽  
pp. 3653-3683
Author(s):  
Yu Shi ◽  
Briana Cameron ◽  
Xian Gu ◽  
Michael Kane ◽  
Peter Peduzzi ◽  
...  
Keyword(s):  
Randomized Trial ◽  
Trial Design ◽  
Treatment Preference ◽  
Selection Effects ◽  
Two Stage ◽  
Self Selection
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