Is improved acess to safe drinking water more effective than improved sanitation in reducing the incidence of diarrhoea?

Is improved access to safe drinking water more effective

than improved sanitation in reducing the incidence of

diarrhoea ?James Jabez Amamoo24th February,2015

OUTLINE OF PRESENTATIONBackgroundPICOInclusion and Exclusion CriteriaTracking my searchCritique of four selected journalsConclusionRecommendationsReferences

BACKGROUNDDiarrhoea is a symptom complex characterized by stools of decreased consistency and increased number ( Clasen et al.,2010)

Diarrhoea is 3 or more loose or fluid stools in a 24 – hour period(WHO 1993)

Diarrhoeal diseases kill an estimated 1.8 million people each year (WHO 2005)

Among infectious diseases, diarrhoea ranks as 3rd leading cause of mortality and morbidity ( Bartram 2003)

Young children are especially vulnerable, bearing 68% of the total burden of diarhoeal disease. (Bartram 2003)

BACKGROUND Con’t Among children younger than five years of age, diarrhoea accounts for 17% of all deaths (UN 2005)

Inadequate water quality and sanitation have long been associated with diarrhoea ( Wolf et al., 2014)

In 2011, 11% of the world population reported using ‘unimproved’ drinking water (defined as unprotected springs and dug wells , surface water and water stored in tanks) (Wolf et al., 2014)

BACKGROUND Con’t

BACKGROUND Con’tIn 2011, 36% had ‘ unimproved’ sanitation ( defined as flush toilets not connected to a sewer or septic system, pit latrines without slab, bucket latrines or open defecation) ( Wolf et al., 2014)

‘ Improved’ and ‘unimproved’ drinking water and sanitation refer to specific sources and facilities as defined by the WHO/UNICEF Joint Monitoring Program (JMP 2013) ( Wolf et al., 2014)

PICO P : All ages

I: Improved access to safe drinking water

C: Improved sanitation

O: Reducing the incidence of diarrhea

INCLUSION AND EXCLUSION CRITERIAINCLUSION CRITERIAPublished Date : 2004 – 2014

Peer Reviewed : YesLanguage : EnglishGeographic subset : AllAge groups: AllSex : AllTypes of Studies used : Systematic Review and Meta Analysis

Ethical approval: Yes Full Text Papers : Yes

EXCLUSION CRITERIAPublished Date : Before 2004

Peer Reviewed : No

Language : Non English

Ethical approval: No

Full Text Papers : No

TRACKING MY SEARCHSearch terms included :Safe drinking water , diarrhoea , sanitation, hygiene, cholera

Databases searched: Cochrane Database of Systematic Reviews, Cinahl Plus, Medline, EMBASE, DARE

TRACKING MY SEARCH con’t Execution of the search strategy yielded 32971 titles and abstracts

These titles and text were further screened and 8672 were obtained for further assessment

On further screening 38 studies full text articles were obtained for further assessment.

Of these 38 , 12 met this review’s inclusion and exclusion criteria

PRISMA checklist for Systematic Reviews was used to obtained the best four

SELECTED JOURNAL PAPERSAssessing the impact of drinking water and sanitation on diarrhoeal disease in low – and middle – income settings: systematic review and meta – regression. Wolf et al., 2014

Water, sanitation, and hygiene interventions to reduce diarrhoea in less developed countries : a systematic review and meta – analysis. Fewtrell et al., 2005

SELECTED JOURNAL PAPERS Interventions to improve water quality for preventing diarrhoea ( Cochrane Review) Clasen et al., 2006

Interventions to improve disposal of human excreta for preventing diarrhoea (Cochrane Review) Clasen et al., 2010

JOURNAL PAPER 1 Assessing the impact of drinking water and sanitation on diarrhoeal disease in low – and middle – income settings: systematic review and meta – regression. Wolf et al., 2014

STRENGHTSClear selection criteria and search strategy

Studies were excluded if they mainly targeted institutions such as schools or the workplace or if they used non – representative population groups

Precise estimate of impact of different intervention types ie baseline water and sanitation conditions

Potential for publication bias was examined with inspection of funnel plots and the use of Beggs and Egger’s test

WEAKNESSESOnly 3 studies used blinding in their assessment of water interventions hence an additional analysis were performed which incorporated bias adjustments based on empirical evidence described by Savoric et al.,2012

Assumptions that estimates derived could be used for all ages.

WEAKNESSESAlthough there was a distinction between “basic piped water” and “pipe water, continuous and safe quality” water interventions, due to lack of studies there was an approximation from the former to the latter by the effect of safe water storage plus the effect of quality improvements on a pipe water system

Cost effectiveness of interventions was not made available

FINDINGS There were large potential reductions in diarrhoeal risk through improvements to both water and sanitation in low and middle income countries

The summary risk ratio of all observations from water interventions in a random meta analysis of the data is 0.66( 0.60 – 0.71)

The overall relative risk for improved over unimproved sanitation on diarrhoea based on meta – analysis was 0.72(0.59 – 0.88)

FINDINGS con’t For water , the most effective household – level intervention was found to be a point-of-use filter in combination with safe water storage

At the community level, introduction of high – quality piped water was found to be most effective

There was evidence that sewer interventions are associated with a greater reduction in diarrhea than basic household sanitation

The estimates for higher quality piped drinking water and sewer connection should however be treated with caution

JOURNAL PAPER 2 Water, sanitation, and hygiene interventions to reduce diarrhoea in less developed countries : a systematic review and meta – analysis. Fewtrell et al., 2005

STRENGHTS Initial selection and data extraction clearly spelt out

Precise methodological criteriaGood significant levels from the Random effects model used to summarize relative risk estimates( p < 0.20)

Criteria for setting out bias known

WEAKNESSES Not all relevant studies were included especially for the sanitation intervention analysis

Studies included did not show cost effectiveness of interventions

None of the studies used assured water quality at the point of consumption

FINDINGSOut of the 4 studies for sanitation intervention analysis only 2 could be used for the meta – analysis pooling a relative risk of 0.68 ( 0.53 – 0.87)

The overall relative risk for the water quality intervention was 0.69( 0.53 – 0.89)

There was evidence of possible publication bias with the water quality interventions

FINDINGS con’tWater quality interventions were generally studied for shorter periods

Sustainability of interventions undetermined since there was little information on the longevity of health related effects and behavior changes after the immediate study period.

JOURNAL PAPER 3Interventions to improve water quality for preventing diarrhoea ( Cochrane Review) Clasen et al., 2006

STRENGHTS It is an update of the Review done by Esrey et al., 1991 and Fewtrell et al., 2005

Interventions aimed at improving the microbiological quality of drinking water, including steps to protect the microbiological integrity of water prior to consumption

There was a wide search of databases, conference proceedings and specialist researchers and organisations ( 30 trials included)

STRENGHTS There was internal validity in selection of studies

There was clear blinding processes for selected studies

Studies selected had follow upsThe 30 trials included over 53476 participants

WEAKNESSESThe meta – analysis result is likely to be artificial precise because

I. They avoided calculating a measure of effect for most trials base on the raw study data

II.Although all trials included in the review assessed outcomes on an individual level, the unit of randomisation was not the individual but a household , group of households, neighborhood or village

III.Some included studies had multiple arms which be included more than once affecting results making a total of 38 discrete comparisons

WEAKNESSESResults could be misleading because of important differences in trial methodology, settings and intervention types although random effects model in pooling the effect estimates the substantial heterogeneity in study results

None of the studies included continually measured the biological performance of their interventions against full range of bacterial, viral and pathogens causing diarrhoea.

FINDINGSThe trials’ main outcome measure was diarrheal but different methods was used to define, assess, and report it. 18 trials used the WHO’s definition of diarrhea, while the other trials used the mother’s or respondent definition.

32 trials reported on household –based interventions which included chlorination , filtration, solar disinfection, combined flocculation and disinfection and improved storage

FINDINGS con’tThe results provided little evidence that the effectiveness of the interventions was associated with sanitation levels

Overall , the household interventions significantly reduced diaarhea episodes amongst all ages pooling an overall risk ratio of 0.43 (CI 0.27 – 0.70)

JOURNAL PAPER 4Interventions to improve disposal of human excreta for preventing diarrhoea (Cochrane Review) Clasen et al., 2010

STRENGHTS Update of previous reviews by Esrey et al., 1985, Fetrwell et al.,2005 and Waddington et al.,2009.

There was internal validity in the selection of the studies that met the review’s criteria

Precise assessment of risk of bias in studies selected

Collectively 13 trials were included in the review covering at least 33417 participants

WEAKNESSES Six of the studies included did not provide clear information on the pre – intervention excreta disposal facilities of the study population even though they served as control

For the multiple component interventions , it was not possible to isolate the effect of the improvement in excreta disposal or ascribe the difference in the outcome solely to the sanitation c0mponent

No clear exploration of publication bias

WEAKNESSES Due to the heterogeneity of studies and unavailability of reliable CI , no pooled effect was calculated

Because all the studies lacked random allocation and the subjective reporting of diarrhoea as outcome measure , the risk of selection bias as well as observer and responder bias in all the trials must be considered high

Only 5 of the studies included solely consisted of such improvements in excreta disposal

FINDINGS Results suggest that interventions to improve excreta disposal are effective in preventing diarrhoeal diseases

Nevertheless , the review provides only limited and preliminary evidence and does not allow the quantification of such an effect

CONCLUSION There are large potential reductions in diarrhoeal disease risk through improvements to both water and sanitation especially in low – and middle-income settings

Any intervention to improve water quality effectiveness is enhanced by compliance with the intervention

The evidence does not suggest that an “improved” supply of water is essential for water quality interventions to prevent diarrhoea

CONCLUSION Water quality interventions appear to be effective in preventing diarrhea regardless of whether they are deployed in settings where sanitation is “improved”

The value of water quality interventions in preventing diarrheal disease depends not only on their effectiveness but also their affordability, sustainability, acceptability and scalability within a vulnerable population

There is an indication that improved access to safe drinking water especially household treatment is more effective than improved sanitation in reducing the incidence of diarrhea

RECOMMENDATIONS Comprehensive cost-effectiveness and cost benefit analysis will help establish the priority that should be attached to water quality interventions by the public sector and non- governmental organisations

Since household interventions appear especially effective, the private sector, which has particular capacity for addressing the needs of householder should be explored as a potential source for developing effective, low-cost water treatment interventions an a wide scale

RECOMMENDATIONSRigorously conducted RCT’s to assess interventions to improve basic sanitation will help clarify the potential contribution of such interventions

It will be important to evaluate both water and sanitation interventions in rural versus urban settings where the challenges of implementation, transmission pathways and exposure levels of diarrhea may vary.

There is also a need for longer – term effectiveness studies in programmatic (not – research driven) settings to assess scalability and sustainability of both water and sanitation interventions

REFERENCES Batram J. New water forum will repeat old message. Bulletin of the World Health Organisation 2003:81(3) : 158

Clasen TF, Bosteon K, Schmidt WP, Boisson S, Fung ICH, Jenkins MW, Scott B, Sugden S, Cairncross S. Interventions to improve disposal of human excreta for preventing diarrhoea. Cochrane Database of Systematic Reviews 2010, Issue 6. Art No.:CD007180. DOI: 10.1002/14651858.CD007180.pub2

Clasen TF, Roberts IG, Rabie T, Schmidt WP, Cairncross S. Interventions to improve water quality for preventing diarrhoea. Cochrane Database of Systematic Reviews 2006, Issue 3 Art. No.: CD004794. DOI : 10.1002/14651858.CD004794.pub2

REFERENCESEsrey SA, Potash JB, Roberts L, Shiff C. Effects of improved water supply and sanitation on ascariasis, diarrhoea, drancunculiasis, hookworm infection, schistosomiasis, and trachoma. Bulletin of the World Health Organisation 1991; 69(5): 609 -21

Fewtrell L, Kaufmann RB, Kay D, Enanoria W, Haller L, Colford JM. Water, sanitation, and hygiene interventions to reduce diarrhoea in less developed countries: a systematic review and meta – analysis. Lancet Infectious Diseases 2005; 5 (1) : 42 -52

Savovic J, Jones HE, Altman DG et al (2012) Influence of reportedstudy design characteristics on intervention effect estimates from randomized, controlled trials. Annals of Internal Medicine 157, 429 -438

REFERENCESUnited Nations Statistics Division. Progress towards the Millennium Development Goals, 1990 – 2005: Goal 4. Reduce child mortality. unstats/un.org/unsd/mi/goals.2005/goal4.pdf (accessed 17 February 2015)

Waddington H, Snilstveit B, White H, Fewtrell L. Water, sanitation and hygiene interventions to combat childhood diarrhoea in developing countries. Journal of Development Effectiveness 2009: Vol 1, issue 3: 295-335

REFERENCESWolf J, Pruss-Ustun A, Cumming O, Bartram J, Bonjour S, Cairncross S, Clasen T, Colford JM, Curtis V, De France J, Fewtrell L, Freeman MC, Gordon B, Hunter PR, Jeandron A, Johnston RB, Mausezahl D, Mathers C, Neira M, Higgins JPT , Assessing the impact of drinking water and sanitation on diarrhoeal disease in low- and middle – income settings: systematic review and meta-regression. Tropical Medicine and International Health 2014:Volume 19 No 8 pp 928 -924

REFERENCESWorld Health Organisation. The

management and prevention of diarrhoea: practical guidelines. 3rd Editiion. Geneva: World Health Organisation, 1993

World Health Organisation . The World Health Report:2005: Make Every Mother and Child Count. Geneva: World Health Organisation, 2005

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