The cluster randomized crossover trial: The effects of attrition in the AB/BA design and how to account for it in sample size calculations

Effectiveness, Safety, and Acceptability of Primaquine Mass Drug Administration in Low-Endemicity Areas in Southern Thailand: Proof-of-Concept Study

BACKGROUND

A challenge in achieving the malaria-elimination target in the Greater Mekong Subregion, including Thailand, is the predominance of Plasmodium vivax malaria, which has shown extreme resilience to control measures.

OBJECTIVE

This proof-of-concept study aimed to provide evidence for implementing primaquine mass drug administration (pMDA) as a strategy for P. vivax elimination in low-endemicity settings.

METHODS

The study employed a mixed-methods trial to thoroughly evaluate the effectiveness, safety, acceptability, and community engagement of pMDA. The quantitative part was designed as a 2-period cluster-crossover randomized controlled trial. The intervention was pMDA augmented to the national prevention and control standards with directly observed treatment (DOT) by village health volunteers. The qualitative part employed in-depth interviews and brainstorming discussions. The study involved 7 clusters in 2 districts of 2 southern provinces in Thailand with persistently low P. vivax transmission. In the quantitative part, 5 cross-sectional blood surveys were conducted in both the pMDA and control groups before and 3 months after pMDA. The effectiveness of pMDA was determined by comparing the proportions of P. vivax infections per 1000 population between the 2 groups, with a multilevel zero-inflated negative binomial model adjusted for cluster and time as covariates and the interaction. The safety data comprised adverse events after drug administration. Thematic content analysis was used to assess the acceptability and engagement of stakeholders.

RESULTS

In the pre-pMDA period, the proportions of P. vivax infections in the pMDA (n=1536) and control (n=1577) groups were 13.0 (95% CI 8.2-20.4) and 12.0 (95% CI 7.5-19.1), respectively. At month 3 post-pMDA, these proportions in the pMDA (n=1430) and control (n=1420) groups were 8.4 (95% CI 4.6-15.1) and 5.6 (95% CI 2.6-11.5), respectively. No statistically significant differences were found between the groups. The number of malaria cases reduced in all clusters in both groups, and thus, the impact of pMDA was inconclusive. There were no major safety concerns. Acceptance among the study participants and public health care providers at local and national levels was high, and they believed that pMDA had boosted awareness in the community.

CONCLUSIONS

pMDA was associated with high adherence, safety, and tolerability, but it may not significantly impact P. vivax transmission. As this was a proof-of-concept study, we decided not to scale up the intervention with larger clusters and samples. An alternative approach involving a targeted primaquine treatment strategy with primaquine and DOT is currently being implemented. We experienced success regarding effective health care workforces at point-of-care centers, effective collaborations in the community, and commitment from authorities at local and national levels. Our efforts boosted the acceptability of the malaria-elimination initiative. Community engagement is recommended to achieve elimination targets.

TRIAL REGISTRATION

Thai Clinical Trials Registry TCTR20190806004; https://www.thaiclinicaltrials.org/show/TCTR20190806004.

The effects of osteopathic manipulative treatment on pain and disability in patients with chronic neck pain: A single-blinded randomized controlled trial

BACKGROUND

Neck pain (NP) affects up to 70% of individuals at some point in their lives. Systematic reviews indicate that manual treatments can be moderately effective in the management of chronic, nonspecific NP. However, there is a paucity of studies specifically evaluating the efficacy of osteopathic manipulative treatment (OMT).

OBJECTIVE

To evaluate the efficacy of OMT in reducing pain and disability in patients with chronic NP.

DESIGN

Single-blinded, cross-over, randomized-controlled trial.

SETTING

University-based, osteopathic manipulative medicine outpatient clinic.

PARTICIPANTS

Ninety-seven participants, 21 to 65 years of age, with chronic, nonspecific NP.

INTERVENTIONS

Participants were randomized to two trial arms: immediate OMT intervention or waiting period first. The intervention consisted of three to four OMT sessions over 4 to 6 weeks, after which the participants switched groups.

MAIN OUTCOME MEASURES

Primary outcome measures were pain intensity (average and current) on the numerical rating scale and Neck Disability Index. Secondary outcomes included Patient-Reported Outcomes Measurement Information System-29 (PROMIS-29) health domains and Fear Avoidance Beliefs Questionnaire. Outcomes obtained prior to the cross-over allocation were evaluated using general linear models and after adjusting for baseline values.

RESULTS

A total of 38 and 37 participants were available for the analysis in the OMT and waiting period groups, respectively. The results showed significantly better primary outcomes in the immediate OMT group for reductions in average pain (-1.02, 95% confidence interval [CI] -1.72, -0.32; p = .005), current pain (-1.02, 95% CI -1.75, -0.30; p = .006), disability (-5.30%, 95% CI -9.2%, -1.3%; p = .010) and improved secondary outcomes (PROMIS) related to sleep (-3.25, 95% CI -6.95, -1.54; p = .003), fatigue (-3.26, 95% CI -6.04, -0.48; p = .022), and depression (-2.59, 95% CI -4.73, -0.45; p = .018). The effect sizes were in the clinically meaningful range between 0.5 and 1 standard deviation. No study-related serious adverse events were reported.

CONCLUSIONS

OMT is relatively safe and effective in reducing pain and disability along with improving sleep, fatigue, and depression in patients with chronic NP immediately following treatment delivered over approximately 4 to 6 weeks.

One SMS a day keeps the stress away? A just-in-time planning intervention to reduce occupational stress among apprentices

BACKGROUND

Occupational stress is one of the main sources of stress in apprentices with physical and psychological health consequences. Just-in-time planning interventions (JITPIs) are one opportunity to deliver intervention components at the right times and locations to optimally support apprentices in stressful situations. The aim of this study was to test the proximal effect of a mobile phone-delivered JITPI to reduce occupational stress in 386 apprentices within a planning intervention.

METHODS

An AB/BA crossover design in which participants were randomly allocated to (A) the planning intervention or (B) the assessment only condition was implemented.

RESULTS

The analyses of the study "ready4life", multilevel modeling, revealed no significant effect of the planning intervention on occupational stress reduction.

CONCLUSIONS

Possible reasons for the missing effect might be the low stress level of participants or the type of the intervention delivery. Since apprenticeships in Switzerland differ considerably, future studies should enable more adapted interventions for the apprentices and consider individual circumstances of stress. Further, the intervention should focus on apprentices with high occupational stress levels or a high-risk of stress. Studies should investigate exactly when and why a person needs support regarding her/his occupational stress. Therefore, objective measurements of stress could be helpful.

“Adipose-derived mesenchymal stem cell therapy for the management of female sexual dysfunction: Literature reviews and study design of a clinical trial”

Hormone imbalance and female sexual dysfunction immensely affect perimenopausal female health and quality of life. Hormone therapy can improve female hormone deficiency, but long-term use increases the risk of cardiovascular diseases and cancer. Therefore, it is necessary to develop a novel effective treatment to achieve long-term improvement in female general and sexual health. This study reviewed factors affecting syndromes of female sexual dysfunction and its current therapy options. Next, the authors introduced research data on mesenchymal stromal cell/mesenchymal stem cell (MSC) therapy to treat female reproductive diseases, including Asherman’s syndrome, premature ovarian failure/primary ovarian insufficiency, and vaginal atrophy. Among adult tissue-derived MSCs, adipose tissue-derived stem cells (ASCs) have emerged as the most potent therapeutic cell therapy due to their abundant presence in the stromal vascular fraction of fat, high proliferation capacity, superior immunomodulation, and strong secretion profile of regenerative factors. Potential mechanisms and side effects of ASCs for the treatment of female sexual dysfunction will be discussed. Our phase I clinical trial has demonstrated the safety of autologous ASC therapy for women and men with sexual hormone deficiency. We designed the first randomized controlled crossover phase II trial to investigate the safety and efficacy of autologous ASCs to treat female sexual dysfunction in perimenopausal women. Here, we introduce the rationale, trial design, and methodology of this clinical study. Because aging and metabolic diseases negatively impact the bioactivity of adult-derived MSCs, this study will use ASCs cultured in physiological oxygen tension (5%) to cope with these challenges. A total of 130 perimenopausal women with sexual dysfunction will receive two intravenous infusions of autologous ASCs in a crossover design. The aims of the proposed study are to evaluate 1) the safety of cell infusion based on the frequency and severity of adverse events/serious adverse events during infusion and follow-up and 2) improvements in female sexual function assessed by the Female Sexual Function Index (FSFI), the Utian Quality of Life Scale (UQOL), and the levels of follicle-stimulating hormone (FSH) and estradiol. In addition, cellular aging biomarkers, including plasminogen activator inhibitor-1 (PAI-1), p16 and p21 expression in T cells and the inflammatory cytokine profile, will also be characterized. Overall, this study will provide essential insights into the effects and potential mechanisms of ASC therapy for perimenopausal women with sexual dysfunction. It also suggests direction and design strategies for future research.

Which factors influence the frequency of participation in longitudinal cohort studies? - An analysis of demographics, social factors, and medical preconditions in participants of the health effects in high level exposure to polychlorinated biphenyls (HELPcB) cohort

The continuous drop out of participants in longitudinal studies is a trend that may be observed in nearly all fields of medical research. A reduced participation rate might compromise the power of statistical analysis as well as lead to an attrition bias of the study. The aim of this analysis was to identify influencing factors on participation frequency in the monitoring program Health Effects in High Level Exposure to polychlorinated biphenyls (HELPcB) study, a cohort investigation of occupationally polychlorinated biphenyls (PCB) exposed individuals. The HELPcB study was initiated in 2010 and consisted of 7 study visits. At the last cross-section in 2019, less than one third of the included patients still actively participated. As possible influencing factors on study participation frequency, demographic, social, and medical characteristics of the participants were examined. In addition, a logistic regression model to predict study participation behavior was calculated. An overall higher frequency of participation was observed, if participants joined the program together with relatives or friends and had a higher age. For PCB plasma levels, an exceedance of the biological reference value (BAR) and further factors, such as (1) professional qualification, (2) later inclusion, (3) type of participant and (4) occupational-related disease notification, significant differences in the participation frequency were observed in the univariate analysis. Only age and joined study participation remained significant in the multivariate logistic regression. In conclusion, it was possible to identify several social and occupational-related factors that influence the frequency of participation of study attendees.

The effect of missing data on design efficiency in repeated cross-sectional multi-period two-arm parallel cluster randomized trials

The reduced efficiency of the cluster randomized trial design may be compensated by implementing a multi-period design. The trial then becomes longitudinal, with a risk of intermittently missing observations and dropout. This paper studies the effect of missing data on design efficiency in trials where the periods are the days of the week and clusters are followed for at least one week. The multilevel model with a decaying correlation structure is used to relate outcome to period and treatment condition. The variance of the treatment effect estimator is used to measure efficiency. When there is no data loss, efficiency increases with increasing number of subjects per day and number of weeks. Different weekly measurement schemes are used to evaluate the impact of planned missing data designs: the loss of efficiency due to measuring on fewer days is largest for few subjects per day and few weeks. Dropout is modeled by the Weibull survival function. The loss of efficiency due to dropout increases when more clusters drop out during the course of the trial, especially if the risk of dropout is largest at the beginning of the trial. The largest loss is observed for few subjects per day and a large number of weeks. An example of the effect of waiting room environments in reducing stress in dental care shows how different design options can be compared. An R Shiny app allows researchers to interactively explore various design options and to choose the best design for their trial.