Interventions to improve water quality and prevent diarrhoea
This Cochrane Review summarizes trials evaluating different interventions to improve water quality and prevent diarrhoea. After searching for relevant trials up to 11 November 2014, we included 55 studies enrolling over 84,000 participants. Most included studies were conducted in low- or middle-income countries (LMICs) (50 studies), with unimproved water sources (30 studies), and unimproved or unclear sanitation (34 studies).
What causes diarrhoea and what water quality interventions might prevent diarrhoea?
Diarrhoea is a major cause of death and disease, especially among young children in low-income countries where the most common causes are faecally contaminated water and food, or poor hygiene practices.
In remote and low-income settings, source-based water quality improvement may include providing protected groundwater (springs, wells, and bore holes) or harvested rainwater as an alternative to surface sources (rivers and lakes). Alternatively water may be treated at the point-of-use in people's homes by boiling, chlorination, flocculation, filtration, or solar disinfection. These point-of-use interventions have the potential to overcome both contaminated sources and recontamination of safe water in the home.
What the research says
There is currently insufficient evidence to know if source-based improvements in water supplies, such as protected wells and communal tap stands or treatment of communal supplies, consistently reduce diarrhoea in low-income settings (very low quality evidence). We found no trials evaluating reliable piped-in water supplies to people's homes.
On average, distributing disinfection products for use in the home may reduce diarrhoea by around one quarter in the case of chlorine products (low quality evidence), and around a third in the case of flocculation and disinfection sachets (moderate quality evidence).
Water filtration at home probably reduces diarrhoea by around a half (moderate quality evidence), and effects were consistently seen with ceramic filters (moderate quality evidence), biosand systems (moderate quality evidence) and LifeStraw® filters (low quality evidence). Plumbed-in filtration has only been evaluated in high-income settings (low quality evidence).
In low-income settings, distributing plastic bottles with instructions to leave filled bottles in direct sunlight for at least six hours before drinking probably reduces diarrhoea by around a third (moderate quality evidence).
Research assessing the effects of household connections and chlorination at the point of delivery will help improve our knowledge base. Evidence indicates the more people use the various interventions for improving water quality, the larger the effects, so research into practical approaches to increase coverage and help assure long term use of them in poor groups will help improve impact.
Citation: Clasen TF, Alexander KT, Sinclair D, Boisson S, Peletz R, Chang HH, Majorin F, Cairncross S. Interventions to improve water quality for preventing diarrhoea. Cochrane Database of Systematic Reviews 2015, Issue 10. Art. No.: CD004794. DOI: 10.1002/14651858.CD004794.pub3.
Portion, package or tableware size for changing selection and consumption of food, alcohol and tobacco
We reviewed the evidence to establish by how much the amounts of food, alcohol or tobacco adults and children select or consume change in response to being presented with larger or smaller-sized (or differently shaped) portions or packages of these products, or of items of tableware (such as plates or glasses) used to consume them.
This review includes 72 randomised controlled trials (RCTs) published up to July 2013 that compared at least two groups of participants, each presented with a different size of a portion, package or item of tableware. Included studies measured the amounts of food, alcohol or tobacco selected and/or consumed by participants, typically over a period of one day or less. Almost all of the included studies investigated food, with only three tobacco studies and no alcohol studies found. Almost all assessed participants' responses to different sizes rather than different shapes. The average age of participants in the different studies ranged from three to 55 years, with more studies involving adults than children and most conducted in the USA. Sources of funding were reported for the majority of studies and there was no evidence of study funding by agencies with commercial interests in their results.
Key findings and quality of evidence Effects of size on consumption: We found evidence that people consistently ate more food or drank more non-alcoholic drinks when offered larger-sized portions, packages or items of tableware than when offered smaller-sized versions. We estimate the size of this effect to be small to moderate among both children and adults. If an effect of this size were sustained across the whole diet it would be equivalent to around a 12% to 16% change in average daily energy intake from food among UK adults. We rated the overall quality of the evidence for this effect as moderate, due to concern about study limitations arising from incomplete or unclear reporting of methods and procedures. From three tobacco studies, we found no effect of longer compared with shorter cigarettes on the amounts of tobacco consumed. We rated the overall quality of evidence for this effect as low due to concerns about study limitations and not having enough evidence.
Effects of shape on consumption: One study found that adults provided with shorter, wider bottles drank larger amounts of water from them, having already poured more, compared with those provided with taller, narrower bottles. However, we rated the quality of this evidence as very low, due to very serious concerns about study limitations and not having enough evidence (only one study with outcome data from 50 participants).
Effects of size on selection: We further found that adults, but not children, consistently chose (selected) more food (including non-alcoholic drinks) when offered larger-sized portions, packages or items of tableware than when offered smaller-sized versions. The estimated size of this effect was again small to moderate. We rated the overall quality of the evidence for this effect as moderate, due to concern about study limitations.
Effects of shape on selection: Evidence from three studies suggested that adults and children provided with shorter, wider bottles or glasses selected increased quantities of non-alcoholic beverages for subsequent consumption, compared with those provided with taller, narrower bottles or glasses. We rated the quality of this evidence as low, again due to concerns about study limitations and unexplained variation in effects between the three studies.
Overall, this review provides the most conclusive evidence to date that acting to reduce the size, availability and appeal of larger-sized portions, packages and tableware has potential to reduce the quantities of food that people select and consume by meaningful amounts. However, it is uncertain whether reducing portions at the smaller end of the size range can be as effective in reducing food consumption as reductions at the larger end of the range. Our findings highlight the need for further research that aims to reduce uncertainties about these effects and address identified gaps in the evidence base, including not having enough evidence for longer-term effects and the absence of evidence about alcohol products.
Citation: Hollands GJ, Shemilt I, Marteau TM, Jebb SA, Lewis HB, Wei Y, Higgins JPT, Ogilvie D. Portion, package or tableware size for changing selection and consumption of food, alcohol and tobacco. Cochrane Database of Systematic Reviews 2015, Issue 9. Art. No.: CD011045. DOI: 10.1002/14651858.CD011045.pub2.
Biological interventions for the management of fatigue in rheumatoid arthritis
What is rheumatoid arthritis and what are biologics?
When you have rheumatoid arthritis, your immune system, which normally fights infection, attacks the lining of your joints, causing swelling, stiffness and pain. The small joints of your hands and feet are usually affected first. There is no cure for rheumatoid arthritis at present, so treatments aim to relieve pain and stiffness and improve your ability to move. Biologics are medications that can reduce joint inflammation, improve symptoms and prevent joint damage.
Fatigue is an important symptom in people with rheumatoid arthritis. However, there is no consensus on the most effective management approaches for it. A number of studies have explored the effects of biologic response modifiers (biologics) in the management of rheumatoid arthritis and associated symptoms such as fatigue. We carried out the current review to evaluate the effects of these therapies on fatigue in adults with rheumatoid arthritis.
We searched for all research published up to 1 April 2014, finding 32 relevant studies. There were 19 studies on five anti-TNF biologics (adalimumab, certolizumab, etanercept, golimumab and infliximab) and 12 studies on five non-anti-TNF biologics (abatacept, canakinumab, rituximab, tocilizumab and an anti-interferon gamma monoclonal antibody).
Altogether 9,946 participants received biologics and 4,682 participants received standard therapy. All but two of the studies were randomised placebo-controlled trials, the gold standard in terms of study quality. We compared the effects of biologics versus placebo. In some studies, participants may have been taking standard therapy for rheumatoid arthritis at the start of the trial. In these studies, investigators added either biologics or placebo treatment to standard therapy. Overall, treatment by biologics led to small to moderate reductions (9 units reduction on a 0-52 scale) in patient-reported fatigue compared with 3 units in participants treated by placebo. It is unclear whether this improvement is due to a reduction in overall disease activity, a direct effect of the biologics or some other mechanism.
Quality of the evidence
There may have been some potential bias in the way investigators analysed data, and some studies did not include all randomised individuals, so we judged the quality of the evidence to be only moderate rather than high.
Citation: Almeida C, Choy EHS, Hewlett S, Kirwan JR, Cramp F, Chalder T, Pollock J, Christensen R. Biologic interventions for fatigue in rheumatoid arthritis. Cochrane Database of Systematic Reviews 2016, Issue 6. Art. No.: CD008334. DOI: 10.1002/14651858.CD008334.pub2.
High dose, high risk? What updated evidence tells us about chemotherapy dosing in early breast cancer
In the 1990s, chemotherapy was established as an effective therapy for early breast cancer, reducing recurrence rates and improving survival. Therefore, it was postulated that higher doses of treatment might be more effective. Indeed, uncontrolled studies of highly selected patients suggested that better rates of survival were achieved by giving doses of chemotherapy so high that bone marrow transplant or other forms of stem cell support were required. There was even a time when the commonest indication for bone marrow transplant in the USA was not leukaemia (where it cures disease) but breast cancer. However, randomized trials were initiated, and we now have an updated systematic review of these trials with mature follow-up.
This review has been updated with new data in the form of extended follow-up from the existing trials. The answer we have now could not be more definitive: there is high-quality evidence that high-dose chemotherapy does not improve survival in breast cancer. The effect sizes are remarkably consistent, the results statistically secure, and follow-up is now available for up to 12 years post-randomization. Increased doses of chemotherapy also carry an increased risk of toxicity, including treatment-related deaths: a lose-lose situation.
How did we come to believe that high-dose chemotherapy might work in the first place, and how can we explain why it doesn’t? The answer to the initial question is human nature. We wanted it to work; there were some preclinical data, and the early 'trials' we had suggested a very good outcome with a high-tech glamorous treatment. However, we simply failed to do due diligence. By definition, women fit enough to undergo high-dose treatment and bone marrow transplantation were very fit and likely to fare better in comparison to historical controls. It transpired that our optimism was based on results that proved too good to be true. Two of those early randomized trials were found to be fabrications of a fraudulent study investigator.
The reasons why this approach doesn’t work must remain speculative. Presumably there is a proportion of cancer cells that remain intrinsically chemo-resistant no matter what the dose is. Additionally, the drugs traditionally used to achieve ablation of the bone marrow (cisplatin, carmustine, thiotepa, etoposide) are not frontline breast cancer drugs. Lastly these trials were done in an era before we understood how subtype-specific breast cancer can be: breast cancers that are sensitive to endocrine therapy or anti-HER2 therapy are lumped in together with tumours that lack hormone and other receptor overexpression. There may indeed be a subtype of breast cancer that is somewhat dose-sensitive, although it seems unlikely that bone marrow ablation would be required.
The review conclusions are definitive, and we believe that the review question can now effectively be closed off. More recent reviews have opened up potential for other therapeutic approaches. In contrast to the high-dose approach, real and valuable progress has been made over the last two decades with the better-defined use of endocrine therapy, the use of taxane chemotherapy, and the use of anti-HER2 therapy . Taken together the message for us in treating breast cancer seems clear: get smarter, not tougher.
Citation: Annabel Goodwin, Melina Willson, Nicholas Wilcken. High dose, high risk? What updated evidence tells us about chemotherapy dosing in early breast cancer[editorial]. Cochrane Database of Systematic Reviews 2016;(5): 10.1002/14651858.ED000113
Healthcare interventions for consumers/public
The Cochrane Collaboration, is a not for profit organisation which produces systematic reviews on the effects of healthcare interventions. These reviews are published in an online database, The Cochrane Library monthly.
What is a systematic review?
A systematic review asks a specific research question about a particular healthcare intervention in a clearly defined group of people with a health condition or problem. These reviews summarise the results of healthcare studies and provides the evidence on the effectiveness of the interventions. Systematic reviews are complex and depend on what clinical trials have been conducted, the quality of the trials and the health outcomes that were measured. The review authors combine the numerical data about the effects of the treatment and the authors assess the benefits and harms for the specific treatment.1
For more information about what consumers can and cannot get from systematic reviews, please visit the Cochrane Consumer website.