Testing equality and interval estimation of the generalized odds ratio in ordinal data under a three-period crossover design

2015 ◽  
Vol 26 (3) ◽  
pp. 1165-1181 ◽  
Author(s):  
Kung-Jong Lui ◽  
Kuang-Chao Chang ◽  
Chii-Dean Lin
Keyword(s):  
Odds Ratio ◽  
Ordinal Data ◽  
Interval Estimation ◽  
Crossover Design ◽  
Test Procedures ◽  
Exact Test ◽  
Number Of Patients ◽  
Interval Estimators ◽  
High Doses ◽  
Stratified Analysis

The crossover design can be of use to save the number of patients or improve power of a parallel groups design in studying treatments to noncurable chronic diseases. We propose using the generalized odds ratio for paired sample data to measure the relative effects in ordinal data between treatments and between periods. We show that one can apply the commonly used asymptotic and exact test procedures for stratified analysis in epidemiology to test non-equality of treatments in ordinal data, as well as obtain asymptotic and exact interval estimators for the generalized odds ratio under a three-period crossover design. We further show that one can apply procedures for testing the homogeneity of the odds ratio under stratified sampling to examine whether there are treatment-by-period interactions. We use the data taken from a three-period crossover trial studying the effects of low and high doses of an analgesic versus a placebo for the relief of pain in primary dysmenorrhea to illustrate the use of these test procedures and estimators proposed here.

Exact tests in binary data under an incomplete block crossover design

2016 ◽  
Vol 27 (2) ◽  
pp. 579-592 ◽  
Author(s):  
Kung-Jong Lui ◽  
Kuang-Chao Chang
Keyword(s):  
Binary Data ◽  
Logistic Regression Model ◽  
Crossover Trial ◽  
Test Procedure ◽  
Crossover Design ◽  
Incomplete Block ◽  
Primary Dysmenorrhea ◽  
Test Procedures ◽  
Exact Test ◽  
High Doses

To improve the power of a parallel groups design and reduce the time length of a crossover trial, we may consider an incomplete block crossover design. Under a distribution-free random effects logistic regression model, we derive an exact test and a Mantel-Haenszel Type of summary test procedure for testing non-equality in binary data when comparing three treatments. We employ Monte Carlo simulation to evaluate the performance of these test procedures. We find that both test procedures developed here can perform well in a variety of situations. We use the data taken as a part of the crossover trial comparing the low and high doses of an analgesic with a placebo for the relief of pain in primary dysmenorrhea to illustrate the use of the proposed test procedures.

scholarly journals Testing Equality of Treatments under an Incomplete Block Crossover Design with Ordinal Responses

2017 ◽  
Vol 13 (1) ◽  
Author(s):  
Kung-Jong Lui
Keyword(s):  
Ordinal Data ◽  
Crossover Trial ◽  
Crossover Design ◽  
Incomplete Block ◽  
Finite Sample ◽  
Test Procedures ◽  
Advantages And Disadvantages ◽  
Relative Treatment Effect ◽  
Patient Responses ◽  
High Doses

AbstractThe generalized odds ratio (GOR) for paired sample is considered to measure the relative treatment effect on patient responses in ordinal data. Under a three-treatment two-period incomplete block crossover design, both asymptotic and exact procedures are developed for testing equality between treatments with ordinal responses. Monte Carlo simulation is employed to evaluate and compare the finite-sample performance of these test procedures. A discussion on advantages and disadvantages of the proposed test procedures based on the GOR versus those based on Wald’s tests under the normal random effects proportional odds model is provided. The data taken as a part of a crossover trial studying the effects of low and high doses of an analgesic versus a placebo for the relief of pain in primary dysmenorrhea over the first two periods are applied to illustrate the use of these test procedures.

Asymptotic and exact interval estimators of the common odds ratio under the sequential parallel comparison design

2018 ◽  
Vol 28 (10-11) ◽  
pp. 3074-3085 ◽  
Author(s):  
Kung-Jong Lui
Keyword(s):  
Odds Ratio ◽  
Controlled Trial ◽  
Placebo Response ◽  
Controlled Study ◽  
Double Blind ◽  
Number Of Patients ◽  
Mental Diseases ◽  
The Common ◽  
Interval Estimators ◽  
Conditional Maximum

When studying treatments for psychiatric or mental diseases in a placebo-controlled trial, we may consider use of the sequential parallel comparison design to reduce the number of patients needed through the reduction of the high placebo response rate. Under the assumption that the odds ratio of responses is constant between phases in the sequential parallel comparison design, we derive the conditional maximum likelihood estimator for the odds ratio. On the basis of the conditional likelihood, we further derive three asymptotic interval and an exact interval estimators for the odds ratio of responses. We employ Monte Carlo simulation to evaluate the performance of these interval estimators in a variety of situations. We find that the asymptotic interval and exact interval estimators developed here can all perform well. We use the double-blind, placebo-controlled study assessing the efficacy of a low dose of aripiprazole adjunctive to antidepressant therapy for treating patients with major depressive disorder to illustrate the use of these estimators.

Notes on Test and Estimation in Comparison of Three Treatments under A Simple Carry-Over Three-Period Model

2018 ◽  
Vol 14 (1) ◽  
Author(s):  
Kung-Jong Lui
Keyword(s):  
Type I Error ◽  
Average Length ◽  
Test Procedure ◽  
Forced Expiratory Volume ◽  
Crossover Design ◽  
Type I ◽  
Test Procedures ◽  
Double Blind ◽  
Interval Estimators ◽  
Carry Over

Abstract Under the three-treatment three-period crossover design with simple carry-over effects, we derive the least-squares estimators for period effects, treatment effects and carry-over effects, as well as their covariance matrix in closed and explicit expressions. Using Monte Carlo simulation, we compare the test procedure adjusting carry-over with that ignoring carry-over with respect to Type I error and power. We further compare interval estimators adjusting carry-over with those ignoring carry-over with respect to the coverage probability and the average length. When the variation of responses within patients is small, the test procedure and interval estimators ignoring carry-over can lose accuracy in the presence of carry-over effects. When the variation of responses within patients is large, this loss of accuracy may become small or even minimal. We note that the loss of efficiency due to the adjustment of carry-over under the simple carry-over three-period crossover design is moderate, and is much less than that found for a two-period crossover design. We use the double-blind three-period crossover trial comparing formoterol solution aerosol and salbutamol suspension aerosol with a placebo for patients suffering from exercise-induced asthma on the forced expiratory volume in one second (FEV1) to illustrate the use of test procedures and interval estimators discussed here.

Electronic cigarettes: How confident and effective are allergists, pulmonologists, and primary care physicians in their practice behavior?

2020 ◽  
Vol 41 (3) ◽  
pp. 192-197
Author(s):  
Sherry S. Zhou ◽  
Alan P. Baptist
Keyword(s):  
Primary Care ◽  
Primary Care Physicians ◽  
Electronic Cigarettes ◽  
The United States ◽  
Fisher Exact Test ◽  
Exact Test ◽  
Knowledge And Beliefs ◽  
Tobacco Cigarette ◽  
Number Of Patients ◽  
Personal Use

Background: There has been a striking increase in electronic cigarette (EC) use in the United States. The beliefs and practices toward ECs among physicians are unknown. Objective: The purpose of this study was to investigate EC practice patterns among allergists, pulmonologists, and primary care physicians. Methods: An anonymous survey was sent to physicians. The survey contained 32 questions and addressed issues related to demographics, cessation counseling behaviors, personal use, and knowledge and beliefs about ECs. Statistical analysis was performed by using analysis of variance, the Pearson χ2 test, Fisher exact test, and logistic regression. Results: A total of 291 physicians completed the survey (222 primary care physicians, 33 pulmonologists, and 36 allergists) for a response rate of 46%. The allergists asked about tobacco cigarette use as frequently as did the pulmonologists and more than the primary care physicians (p < 0.001), but they rarely asked about EC use. The pulmonologists scored highest on self-reported knowledge on ECs, although all the groups answered <40% of the questions correctly. The allergists did not feel as comfortable about providing EC cessation counseling as did the pulmonologists and primary care physicians (p < 0.001). All three groups were equally unlikely to recommend ECs as a cessation tool for tobacco cigarette users. Conclusion: Allergists lacked knowledge and confidence in providing education and cessation counseling for EC users. As the number of patients who use these products continues to increase, there is an urgent need for all physicians to be comfortable and knowledgeable with counseling about ECs.

An Analysis of Dental Implants Survival and Success

2018 ◽  
Vol 69 (9) ◽  
pp. 2465-2466
Author(s):  
Iustin Olariu ◽  
Roxana Radu ◽  
Teodora Olariu ◽  
Andrada Christine Serafim ◽  
Ramona Amina Popovici ◽  
...  
Keyword(s):  
Risk Factors ◽  
Cohort Study ◽  
Medical History ◽  
Retrospective Cohort Study ◽  
Odds Ratio ◽  
Retrospective Cohort ◽  
Demographic Data ◽  
Kaplan Meier ◽  
Number Of Patients ◽  
Health Related

Osseointegration of a dental implant may encounter a variety of problems caused by various factors, as prior health-related problems, patients� habits and the technique of the implant inserting. Retrospective cohort study of 70 patients who received implants between January 2011- April 2016 in one dental unit, with Kaplan-Meier method to calculate the probability of implants�s survival at 60 months. The analysis included demographic data, age, gender, medical history, behavior risk factors, type and location of the implant. For this cohort the implants�survival for the first 6 months was 92.86% compared to the number of patients and 97.56% compared to the number of total implants performed, with a cumulative failure rate of 2.43% after 60 months. Failures were focused exclusively on posterior mandible implants, on the percentage of 6.17%, odds ratio (OR) for these failures being 16.76 (P = 0.05) compared with other localisations of implants, exclusively in men with median age of 42 years.

Sex and Gender Differences in Rilpivirine based ART - Data from the HIVCENTER Frankfurt

2019 ◽  
Vol 17 (5) ◽  
pp. 368-374
Author(s):  
G. Schüttfort ◽  
K. Philipp ◽  
P. de Leuw ◽  
E. Herrmann ◽  
G. Kann ◽  
...  
Keyword(s):  
Odds Ratio ◽  
Virologic Failure ◽  
Response Rates ◽  
Virologic Response ◽  
Close Monitoring ◽  
Sex And Gender ◽  
Overall Response ◽  
Number Of Patients ◽  
And Gender ◽  
Gender Specific

Objectives: While Rilpivirine has shown high overall response rates in treatment-naïve patients without sex and gender specific differences in clinical trials, Sex and gender specific data in treatment experienced patients receiving rilpivirine are still limited. We conducted a 48 week efficacy and safety analysis in naïve and treatment experienced men and women using retrospective data from the HIVCENTER Frankfurt. Materials and methods: In this retrospective observational study data of all patients who received a rilpivirine based regimen at the HIVCENTER between March 2011 and December 2015 were analyzed. Primary endpoint was the proportion of patients with any discontinuation until week 48. Virologic response rates (FDA snapshot analysis; HIV-1 RNA <50 copies/mL) were assessed at week 48. Results: 194 patients (34% female) were included in the analysis. 74% were treatment-experienced and 26% naïve, respectively. Discontinuations were observed in 31 (15.9%) patients. Regarding sex differences, the proportion of discontinuations was significantly higher in women than in men (24.2% vs. 11.7%; p=0.024; ODDS-Ratio = 2.41; CI 1.12 – 5.18). Virologic failure occurred in 8 PLWHIV (4.1%). Conclusions: While virologic overall response rates to rilpivirine based ART were high for both treatment-experienced and -naïve patients the proportion of discontinuations was significantly higher in women (24.2% vs. 11.7%; p = 0.024; ODDS-Ratio = 2.41; CI 1.12 – 5.18). Although the total number of patients with virologic failure was low (4.1%), the higher rate of ART discontinuations in female patients receiving RPV require close monitoring in the first months of treatment addressing special needs of women living with HIV.

scholarly journals Remeex® System Effectiveness in Male Patients with Stress Urinary Incontinence

2021 ◽  
Vol 10 (10) ◽  
pp. 2121
Author(s):  
Gerardo-Alfonso Márquez-Sánchez ◽  
Bárbara-Yolanda Padilla-Fernández ◽  
Miguel Perán-Teruel ◽  
Pedro Navalón-Verdejo ◽  
Sebastián Valverde-Martínez ◽  
...  
Keyword(s):  
Urinary Incontinence ◽  
Stress Urinary Incontinence ◽  
Surgical Techniques ◽  
High Survival ◽  
Complication Rates ◽  
Exact Test ◽  
Number Of Patients ◽  
Male Stress Urinary Incontinence ◽  
Group B

Background: When conservative management fails, patients with stress urinary incontinence (SUI) are considered for surgical treatment. Simpler, more economical and less invasive surgical techniques, such as the Remeex® system, have been developed. Objectives: To analyze the objective effectiveness of the Remeex® system in the treatment of male stress urinary incontinence. To study survival and complication rates of the Remeex® system in male SUI patients. Materials and methods: Prospective observational study between July 2015 and May 2020. Group A (n = 7; GA) patients with mild SUI. Group B (n = 22; GB) patients with moderate SUI. Group C (n = 18; GC) patients with severe SUI. Effectiveness was assessed by the number of patients achieving complete and partial dryness. Complete dryness was defined as patients using 0–1 safety pads per day; partial dryness as a >50% reduction in the number of pads used. Results were analyzed using descriptive statistics, Student’s t-test. Chi2, Fisher’s exact test, ANOVA, and multivariate analysis. Significance was set at p < 0.05. Results: Mean age 69.76 years, mean follow-up 33.52 months. Objective effectiveness was observed in 89.36% of patients with incontinence. The effectiveness was 85.71% in GA, 90.91% in GB and 88.89% in GC. There were no significant differences among groups (p = 1.0000). 34.04% of patients with an implant required at least one readjustment, while 66.00% did not require any. There were no significant differences among groups (p = 0.113) Chi2 = 4.352. 95.74% of implants remained in place by the end of follow-up. We observed complications in 17.02% of patients. Conclusions: Remeex® system is an effective and safe method for male stress urinary incontinence treatment, regardless of the severity of the incontinence, with high survival and low complication and removal rates. System readjustments are required in one-third of the cases.

Hardy-Weinberg Testing for Continuous Data

Genetics ◽  
1997 ◽  
Vol 147 (4) ◽  
pp. 1965-1975
Author(s):  
Lauren M McIntyre ◽  
B S Weir
Keyword(s):  
Intraclass Correlation ◽  
Kernel Density ◽  
Variable Number ◽  
Continuous Data ◽  
Test Statistic ◽  
Test Procedures ◽  
Chi Square ◽  
Exact Test ◽  
Chi Square Test ◽  
The Many

Abstract Estimation of allelic and genotypic distributions for continuous data using kernel density estimation is discussed and illustrated for some variable number of tandem repeat data. These kernel density estimates provide a useful representation of data when only some of the many variants at a locus are present in a sample. Two Hardy-Weinberg test procedures are introduced for continuous data: a continuous chi-square test with test statistic TCCS and a test based on Hellinger's distance with test statistic TCCS. Simulations are used to compare the powers of these tests to each other and to the powers of a test of intraclass correlation TIC, as well as to the power of Fisher's exact test TFET applied to discretized data. Results indicate that the power of TCCS is better than that of THD but neither is as powerful as TFET. The intraclass correlation test does not perform as well as the other tests examined in this article.

Sign in / Sign up

Export Citation Format

Share Document