September 2015 · Issue 145
In this issue:
- New video added to NCCMTs series: Understanding Research Evidence
- New from Public Health+
- 2-part webinar from NCCMT - Register now for Part 2!
- Upcoming webinars from Health Evidence
New video added to NCCMTs series: Understanding Research Evidence
Making Sense of a Standardized Mean Difference
A Standardized Mean Difference, or SMD for short, is a summary statistic used when the studies in a meta-analysis assess the same outcome but measure it in different ways.* An SMD is not tied to any specific unit of measurement, so it can be challenging to know how to interpret it, and how to use it to inform your public health decisions.
In this seven-minute video, we invite you to roll up your sleeves and conquer SMDs.
We also discuss why standardized mean differences are used in meta-analyses and how to interpret SMDs that are reported as positive or negative values.
The video uses the example of teen mental health to demonstrate how an SMD is calculated.
Greater understanding of SMDs will help you apply evidence in your practice, contributing to enhanced public health outcomes.
* Faraone. S. (2008). Interpreting Estimates of Treatment Effects: Implications for Managed Care. Pharmacy and Therapeutics, December 2008; 33(12): 700-703, 710-711. PMCID: PMC2730804
About the series
These short videos to explain some important terms that you may encounter in research evidence. They provide a valuable refresher or useful introduction to terms public health professionals need to make good decisions using research evidence.
Watch all the videos in the series!
The videos are available on YouTube and on the NCCMT website (http://www.nccmt.ca/resources/multimedia-eng.html#ure). They are part of a series of products and services on the website and in the Learning Centre (http://www.nccmt.ca/learningcentre/index.php#main.html) designed to help you make good public health decisions, based on the best research evidence available.
New from Public Health+
Hormonal and intrauterine methods for contraception for women aged 25 years and younger.
BACKGROUND: Women between the ages of 15 and 24 years have high rates of unintended pregnancy; over half of women in this age group want to avoid pregnancy. However, women under age 25 years have higher typical contraceptive failure rates within the first 12 months of use than older women. High discontinuation rates may also be a problem in this population. Concern that adolescents and young women will not find hormonal or intrauterine contraceptives acceptable or effective might deter healthcare providers from recommending these contraceptive methods. OBJECTIVES: To compare the contraceptive failure (pregnancy) rates and to examine the continuation rates for hormonal and intrauterine contraception among young women aged 25 years and younger. SEARCH METHODS: We searched until 4 August 2015 for randomized controlled trials (RCTs) that compared hormonal or intrauterine methods of contraception in women aged 25 years and younger. Computerized databases included the Cochrane Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, POPLINE, CINAHL, and LILACS. We also searched for current trials via ClinicalTrials.gov and the International Clinical Trials Registry Platform (ICTRP). SELECTION CRITERIA: We considered RCTs in any language that reported the contraceptive failure rates for hormonal or intrauterine contraceptive methods, when compared with another contraceptive method, for women aged 25 years and younger. The other contraceptive method could have been another intrauterine contraceptive, another hormonal contraceptive or different dose of the same method, or a non-hormonal contraceptive. Treatment duration must have been at least three months. Eligible trials had to include the primary outcome of contraceptive failure rate (pregnancy). The secondary outcome was contraceptive continuation rate. DATA COLLECTION AND ANALYSIS: One author conducted the primary data extraction and entered the information into Review Manager. Another author performed an independent data extraction and verified the initial entry. For dichotomous outcomes, we computed the Mantel-Haenszel odds ratio (OR) with 95% confidence interval (CI). Because of disparate interventions and outcome measures, we did not conduct meta-analysis. MAIN RESULTS: Five trials met the inclusion criteria. The studies included a total of 1503 women, with a mean of 301 participants. The trials compared the following contraceptives: combined oral contraceptive (COC) versus transdermal contraceptive patch, vaginal contraceptive ring, or levonorgestrel intrauterine system 20 microg/day (LNG-IUS 20); LNG-IUS 12 microg/day (LNG-IUS 12) versus LNG-IUS 16 microg/day (LNG-IUS 16); and LNG-IUS 20 versus the copper T380A intrauterine device (IUD). In the trials comparing two different types of methods, the study arms did not differ significantly for contraceptive efficacy or continuation. The sample sizes were small for two of those studies. The only significant outcome was that a COC group had a higher proportion of women who discontinued for `other personal reasons` compared with the group assigned to the LNG-IUS 20 (OR 0.27, 95% CI 0.09 to 0.85), which may have little clinic relevance. The trial comparing LNG-IUS 12 versus LNG-IUS 16 showed similar efficacy over one and three years. In three trials that examined different LNG-IUS, continuation was at least 75% at 6 to 36 months. AUTHORS` CONCLUSIONS: We considered the overall quality of evidence to be moderate to low. Limitations were due to trial design or limited reporting. Different doses in the LNG-IUS did not appear to influence efficacy over three years. In another study, continuation of the LNG-IUS appeared at least as high as that for the COC. The current evidence was insufficient to compare efficacy and continuation rates for hormonal and intrauterine contraceptive methods in women aged 25 years and younger.
The full text may be available from PubMed
Hand washing promotion for preventing diarrhoea.
BACKGROUND: Diarrhoea accounts for 1.8 million deaths in children in low- and middle-income countries (LMICs). One of the identified strategies to prevent diarrhoea is hand washing. OBJECTIVES: To assess the effects of hand washing promotion interventions on diarrhoeal episodes in children and adults. SEARCH METHODS: We searched the Cochrane Infectious Diseases Group Specialized Register (27 May 2015); CENTRAL (published in the Cochrane Library 2015, Issue 5); MEDLINE (1966 to 27 May 2015); EMBASE (1974 to 27 May 2015); LILACS (1982 to 27 May 2015); PsycINFO (1967 to 27 May 2015); Science Citation Index and Social Science Citation Index (1981 to 27 May 2015); ERIC (1966 to 27 May 2015); SPECTR (2000 to 27 May 2015); Bibliomap (1990 to 27 May 2015); RoRe, The Grey Literature (2002 to 27 May 2015); World Health Organization (WHO) International Clinical Trial Registry Platform (ICTRP), metaRegister of Controlled Trials (mRCT), and reference lists of articles up to 27 May 2015. We also contacted researchers and organizations in the field. SELECTION CRITERIA: Individually randomized controlled trials (RCTs) and cluster-RCTs that compared the effects of hand washing interventions on diarrhoea episodes in children and adults with no intervention. DATA COLLECTION AND ANALYSIS: Three review authors independently assessed trial eligibility, extracted data, and assessed risk of bias. We stratified the analyses for child day-care centres or schools, community, and hospital-based settings. Where appropriate, incidence rate ratios (IRR) were pooled using the generic inverse variance method and random-effects model with 95% confidence intervals (CIs). We used the GRADE approach to assess the quality of evidence. MAIN RESULTS: We included 22 RCTs: 12 trials from child day-care centres or schools in mainly high-income countries (54,006 participants), nine community-based trials in LMICs (15,303 participants), and one hospital-based trial among people with acquired immune deficiency syndrome (AIDS) (148 participants).Hand washing promotion (education activities, sometimes with provision of soap) at child day-care facilities or schools prevents around one-third of diarrhoea episodes in high income countries (rate ratio 0.70; 95% CI 0.58 to 0.85; nine trials, 4664 participants, high quality evidence), and may prevent a similar proportion in LMICs but only two trials from urban Egypt and Kenya have evaluated this (rate ratio 0.66, 95% CI 0.43 to 0.99; two trials, 45,380 participants, low quality evidence). Only three trials reported measures of behaviour change and the methods of data collection were susceptible to bias. In one trial from the USA hand washing behaviour was reported to improve; and in the trial from Kenya that provided free soap, hand washing did not increase, but soap use did (data not pooled; three trials, 1845 participants, low quality evidence).Hand washing promotion among communities in LMICs probably prevents around one-quarter of diarrhoea episodes (rate ratio 0.72, 95% CI 0.62 to 0.83; eight trials, 14,726 participants, moderate quality evidence). However, six of these eight trials were from Asian settings, with only single trials from South America and sub-Saharan Africa. In six trials, soap was provided free alongside hand washing education, and the overall average effect size was larger than in the two trials which did not provide soap (soap provided: rate ratio 0.66, 95% CI 0.56 to 0.78; six trials, 11,422 participants; education only: rate ratio: 0.84, 95% CI 0.67 to 1.05; two trials, 3304 participants). There was increased hand washing at major prompts (before eating/cooking, after visiting the toilet or cleaning the baby`s bottom), and increased compliance to hand hygiene procedure (behavioural outcome) in the intervention groups than the control in community trials (data not pooled: three trials, 3490 participants, high quality evidence).Hand washing promotion for the one trial conducted in a hospital among high-risk population showed significant reduction in mean episodes of diarrhoea (1.68 fewer) in the intervention group (Mean difference 1.68, 95% CI 1.93 to 1.43; one trial, 148 participants, moderate quality evidence). There was increase in hand washing frequency, seven times per day in the intervention group versus three times in the control in this hospital trial (one trial, 148 participants, moderate quality evidence).We found no trials evaluating or reporting the effects of hand washing promotions on diarrhoea-related deaths, all-cause-under five mortality, or costs. AUTHORS` CONCLUSIONS: Hand washing promotion probably reduces diarrhoea episodes in both child day-care centres in high-income countries and among communities living in LMICs by about 30%. However, less is known about how to help people maintain hand washing habits in the longer term.
The full text may be available from PubMed
2-part webinar from NCCMT - Register now for Part 2!
NCCMT is excited to present the second of this two-part webinar featuring the Policy Readiness Tool
Part 1: Overview of the Policy Readiness Tool
Learn how the Policy Readiness Tool was developed and how to use the tool in your practice.
View this presentation on YouTube: https://youtu.be/FPzViyniKDQ
Part 2: Using the Policy Readiness Tool in Public Health
October 1, 2015
1:00pm– 2:30pm (EST).
Hear the stories of how public health practitioners have used the Policy Readiness Tool in practice and discuss challenges and successes when applying the Policy Readiness Tool.
Click here for more information or to register for Part 2: http://ow.ly/Qc50a
Upcoming webinars from Health Evidence
A monthly series from health Evidence TM featuring review authors presenting their findings
School-based curricula for preventing smoking in children and adolescents: What's the evidence?
September 24th
2:00-3:00pm EDT
Join Dr. Roger Thomas, Professor, Faculty of Medicine, University of Calgary, for an overview of findings from his review examining the effectiveness of school-based smoking prevention curricula in keeping children never-smokers:
Thomas, R. E., McLellan, J., & Perera, R. (2015). Effectiveness of school-based smoking prevention curricula: Systematic review and meta-analysis. http://www.healthevidence.org/view-article.aspx?a=28703 BMJ Open, 5(3).
Click here to register: http://ow.ly/R6sW6
Overweight / obesity prevention, treatment, and maintenance from childhood to adulthood: Discussing review-level evidence
October 14th
1:00-2:30pm EDT
Join Dr. Leslea Peirson, Review Coordinator, McMaster Evidence Review and Synthesis Centre, for an overview of key messages from a series of five recent reviews published in CMAJ Open examining overweight and obesity prevention, treatment, and weight maintenance strategies among children, youth, and adult populations.
Click here to register: http://ow.ly/R6tcO
Food supplementation programmes for improving the health of socio-economically disadvantaged children: What’s the evidence?
November 23
1:00-2:30pm EST
Join Dr. Elizabeth Kristjansson, Professor, School of Psychology, University of Ottawa, for an overview of findings from her latest Cochrane review examining the effectiveness of food supplementation programmes for improving the physical and psychosocial health of socio-economically disadvantaged children:
Kristjansson E., Francis D.K., Liberato S., Benkhalti J.M., Welch V., Batal M., et al. (2015). Food supplementation for improving the physical and psychosocial health of socio-economically disadvantaged children aged three months to five years. Cochrane Database of Systematic Reviews,2015(2), Art. No.: CD009924
