Blocked Randomization with Randomly Selected Block Sizes

When planning a randomized clinical trial, careful consideration must be given to how participants are selected for various arms of a study. Selection and accidental bias may occur when participants are not assigned to study groups with equal probability. A simple random allocation scheme is a process by which each participant has equal likelihood of being assigned to treatment versus referent groups. However, by chance an unequal number of individuals may be assigned to each arm of the study and thus decrease the power to detect statistically significant differences between groups. Block randomization is a commonly used technique in clinical trial design to reduce bias and achieve balance in the allocation of participants to treatment arms, especially when the sample size is small. This method increases the probability that each arm will contain an equal number of individuals by sequencing participant assignments by block. Yet still, the allocation process may be predictable, for example, when the investigator is not blind and the block size is fixed. This paper provides an overview of blocked randomization and illustrates how to avoid selection bias by using random block sizes

Season of Birth and Risk for Adult Onset Glioma

Adult onset glioma is a rare cancer which occurs more frequently in Caucasians than African Americans, and in men than women. The etiology of this disease is largely unknown. Exposure to ionizing radiation is the only well established environmental risk factor, and this factor explains only a small percentage of cases. Several recent studies have reported an association between season of birth and glioma risk. This paper reviews the plausibility of evidence focusing on the seasonal interrelation of farming, allergies, viruses, vitamin D, diet, birth weight, and handedness. To date, a convincing explanation for the occurrence of adult gliomas decades after a seasonal exposure at birth remains elusive

The Association between Trust in Health Care Providers and Medication Adherence among Black Women with Hypertension

Background: Black women have the highest prevalence of hypertension in the world. Reasons for this disparity are poorly understood. The historical legacy of medical maltreatment of Blacks in the U.S. provides some insight into distrust in the medical profession, refusal of treatment, and poor adherence to treatment regimens. Methods: Black women (N = 80) who were prescribed antihypertensive medications were recruited from urban communities in North Carolina. Study participants completed the Trust in Physician and Hill-Bone Compliance to High Blood Pressure Therapy questionnaires. An exact discrete-event model was used to examine the relationship between trust and medication adherence. Results: Mean age of study participants was 48 ± 9.2 years. The majority of participants (67%) were actively employed and 30% had incomes at or below the federal poverty level. Increasing levels of trust in the health care provider was independently associated with greater medication adherence (PTrend = 0.015). Conclusion: Black women with hypertension who trusted their health care providers were more likely to be adherent with their prescribed antihypertensive medications than those who did not trust their health care providers. Findings suggest that trusting relationships between Black women and health care providers are important to decreasing disparate rates of hypertension

Racial Differences in Survival among Hemodialysis Patients after Coronary Artery Bypass Grafting

The aim of this study was to examine racial differences in long-term survival among hemodialysis patients after coronary artery bypass grafting (CABG). To our knowledge this has not been previously addressed in the literature. Black and white hemodialysis patients undergoing first-time, isolated CABG procedures between 1992 and 2011 were compared. Survival probabilities were computed using the Kaplan-Meier product-limit method and stratified by race. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. A total of 207 (2%) patients were on hemodialysis at the time of CABG. White (n = 80) hemodialysis patients had significantly decreased 5-year survival compared with black (n = 127) patients (adjusted HR = 1.9, 95% CI = 1.2–2.8). Our finding provides useful outcome information for surgeons, primary care providers, and their patients

Trauma Affecting Asian-Pacific Islanders in the San Francisco Bay Area

Trauma is a transgenerational process that overwhelms the community and the ability of family members to cope with life stressors. An anthropologist trained in ethnographic methods observed three focus groups from a non-profit agency providing trauma and mental health services to Asian Americans living in the San Francisco Bay Area of United States. Supplemental information also was collected from staff interviews and notes. Many of the clients were immigrants, refugees, or adult children of these groups. This report consisted of authentic observations and rich qualitative information to characterize the impact of trauma on refugees and immigrants. Observations suggest that collective trauma, direct or indirect, can impede the success and survivability of a population, even after many generations

Refugee Policy Implications of U.S. Immigration Medical Screenings: A New Era of Inadmissibility on Health-Related Grounds

Refugees frequently face extended delays in their efforts to enter the United States (U.S.) and those who are successful, in many cases, encounter overwhelming obstacles, inadequate resources, and a complex system of legal barriers. Travel restrictions based on equivocal health concerns and a drop in refugee admittance ceilings have complicated the situation. The authors retrieved and analyzed peer-reviewed journal articles, government agency press releases, media postings, epidemiologic factsheets, and relevant lay publications to critically assess U.S. policy regarding refugee resettlement based on health-related grounds. While refugees arguably exhibit an increased incidence of measles and tuberculosis compared with the U.S. population, the legitimacy of the medical examination will be undermined if other diseases that are endemic to refugee populations, yet currently deemed admissible, are used to restrict refugees from entering the U.S. This paper addressees the historic refugee policy of the U.S. and its consequent effect on the health of this vulnerable population. The needs of refugees should be carefully considered in the context of increased disease burden and the associated health care challenges of the country as a whole