2 Minute Medicine Rewind September 22 – September 29, 2014

In this section, we highlight the key high-impact studies, updates, and analyses published in medicine during the past week.

Ebola Virus Disease in West Africa — The First 9 Months of the Epidemic and Forward Projections

The current Ebola virus disease (EVD) epidemic in west Africa, first beginning in December 2013, has now reached historically high numbers with 4507 infections and 2296 deaths in five countries by September 14, 2014, making it larger than all previous EVD epidemics combined. In this study, the WHO Ebola team documents the clinical and epidemiologic characteristics of the EVD epidemic during its first 9 months with projections for its future spread. Researchers analyzed a specific well-documented subset of 3343 confirmed and 667 probable Ebola cases in order to assess disease characteristics. The WHO team found that most EVD cases were between the ages of 15-44 years old. The case fatality rate has been 70.8% (95% CI: 69-73). A patient infected with EVD was asymptomatic for a period of approximately 11.4 days before developing symptoms (the incubation period) and would cause symptomatic disease in another person after approximately 15.3 days of symptoms (the serial interval). In Guinea, Liberia, or Sierra Leone respectively, an infected person would be expected to spread the disease to 1.81 (95% CI 1.60-2.03), 1.51 (1.41-1.60), or 1.38 (1.27-1.51) other people which would translate to a case doubling time of 15.7 (95% CI: 12.9-20.3), 23.6 (20.2-28.2), or 30.2 (23.6-42.3) days. These numbers are similar to those of previous EVD epidemics but indicate a bleak situation given the magnitude of cases already involved and the poor efficacy of existing efforts to combat the disease. The number of cases and deaths from EVD continues to spread at an alarming rate, thus highlighting the need for much more effective control measures.

Effect of Enhanced Information, Values Clarification, and Removal of Financial Barriers on Use of Prenatal Genetic Testing

Prenatal genetic testing, once reserved for pregnant patients of advanced age and those with specific risk factors, has now been incorporated into routine prenatal care. However, evidence seems to show that women are often not fully informed of the risks and benefits of such testing and may be undergoing unnecessary screenings that would not ultimately change their decision making. Investigators sought to better understand the preferences of women who were more fully informed about testing options and were not subject to financial barriers in considering screening and intervention. In this randomized control trial, 710 patients were assigned to receive either a computerized, interactive decision-support guide with the option of free prenatal testing or usual care. Researchers found that when compared to controls, women in the intervention group displayed significantly higher knowledge scores about prenatal genetic testing and could more accurately estimate both amniocentesis-related miscarriage risk and risk of carrying a fetus with trisomy 21. Patients in the intervention group were less likely to undergo invasive diagnostic testing (5.9% vs. 12.3%, OR: 0.45, 95% CI: 0.25-0.80) let alone any genetic screening at all (25.6% vs. 20.4%, OR: 3.30, 95% CI: 1.43-7.64). This study therefore suggests that computerized, interactive decision-support guides can better inform patients about the risk of prenatal genetic testing and that women, when more knowledgeable about the risks and benefits of screening, may choose to forego prenatal testing more frequently.

HMG-coenzymeA reductase inhibition, type 2 diabetes, and bodyweight: evidence from genetic analysis and randomised trials

Recent studies suggest that statins increase the risk of new-onset type 2 diabetes. However, it remains unknown whether this is due to the inhibition of 3-hydroxy-3-methylglutaryl-CaA reductase (HMGCR) or another drug effect. In this meta-analysis and genetic analysis, investigators summarized the effects of statins on indicators of metabolic dysfunction and similarly sought to see whether individuals with one of two known HMGCR mutations, rs17238484-G allele or rs12916-T allele, displayed similar effects. Investigators found that,using data from 129,170 individuals in randomized trials, statins lowered LDL cholesterol by 0.92 mmol/L (95% CI 0.18-1.67) after 1 year and additionally increased bodyweight by 0.24 kg (95% CI: 0.10-0.38), 0.33 kg (0.24-0.42), or -0.15 kg (-0.39-0.08) across all trials, placebo/standard-care controlled trials, or intensive vs. moderate-dose trials respectively after a mean of 4.2 years of follow-up. Statins also increased the odds of developing new-onset type 2 diabetes with odds ratios of 1.12 (95% CI 1.06-1.18), 1.11 (1.03-1.20), and 1.12 (1.04-1.22) in these trials respectively. In the genetic analysis, researchers analyzed genetic data from 223, 463 individuals and found that on average, each additional rs17238484-G allele decreased LDL levels by 0.06 mmol/L (95% CI 0.05-0.07), increased body weight by 0.30 kg (0.18-0.43), waist circumference by 0.32 cm (0.16-0.47), plasma insulin concentration by 1.62% (0.53-2.72), and plasma glucose concentration by 0.23% (0.02-0.44). This translated to a higher risk of developing type 2 diabetes (OR per allele: 1.02, 95% CI: 1.00-1.05). The rs12916-T allele showed similar effects (1.06, 1.03-1.09). The results of this study therefore show that both statins and mutations of the HMGCR gene produce similar effects with regards to metabolic dysfunction and ultimately an increased risk for developing new onset type 2 diabetes and that the increased risk of type 2 diabetes from statins may be partially due to HMGCR inhibition.

Oral Glucocorticoid-Sparing Effect of Mepolizumab in Eosinophilic Asthma

Patients with severe eosinophilic asthma often need frequent treatment with systemic glucocorticoids, which precipitates a host of adverse effects. Mepolizumab is a humanized monoclonal antibody against interleukin-5, which has been shown to reduce asthma exacerbations. However, the full effect of mepolizumab in reducing glucocorticoid use has not been measured.   In this randomized control trial, 135 patients with severe eosinophilic asthma received either 100mg of mepolizumab or placebo every 4 weeks for 20 weeks in additional to standard asthma therapy. Researchers found that the intervention group displayed a median percentage reduction from baseline in glucocorticoid dose by 50% in comparison to 0% in the control group (p = 0.007). Patients in the intervention group also had a 32% reduction in yearly rate of asthma exacerbations (1.44 vs. 2.12, p=0.04) and had reduced asthma symptoms by 0.52 points on the Asthma Control Questionnaire 5 (p = 0.004). There was no difference in safety profile between the two groups. This study therefore shows that mepolizumab may be an effective way for reducing corticosteroid use and gaining better control of asthma symptoms in patients with severe eosinophilic asthma requiring oral glucocorticoid therapy.

Internet-based intervention for smoking cessation (StopAdvisor) in people with low and high socioeconomic status: a randomised controlled trial

Digital interventions for smoking cessation are promising because of their ease of distribution and low cost.   However, there has been little evidence showing clear effectiveness of such interventions and further debate about whether internet-based interventions are effective in low socioeconomic status populations, which have lower literacy rates. In this randomized control trial, researchers randomized 4613 daily smokers to an interactive smoking cessation website designed for low socioeconomic status individuals, called StopAdvisor, or an information-only website. Investigators found that overall, there was no difference between the intervention and control groups in achieving the primary outcome of 6 months of smoking abstinence (10% vs. 10%, RR: 1.06, 95% CI: 0.89-1.27, p = 0.49).   However when the patients were further stratified, researchers did note increased effectiveness in achieving the primary outcome among low socioeconomic status patients (8% vs. 6%, RR: 1.36, 95% CI: 1.00-1.86) but not among high socioeconomic status patients. This study therefore provides evidence of an interactive website for smoking cessation that is more effective in helping low socioeconomic status smokers achieve abstinence than simply providing online information.

Image: PD

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