Update on evidence of the effec0veness of HWTS to prevent diarrhoeal diseases

Transcription

1 Update on evidence of the effec0veness of HWTS to prevent diarrhoeal diseases Thomas Clasen, JD, PHD Professor of Environmental Health, Emory University Reader in Water, Sanita0on and Health, LSHTM!!

2 Disclosure/Poten0al Conflicts UNICEF WHO WaterAid DelAgua Health and Development Unilever/Hindustan Unilever Ltd. PATH PSI Medentech Vestergaard Frandsen Procter & Gamble USAID DfID Bill and Melinda Gates Founda0on

3 Previous Reviews Pooled es(mate RR (95%CI) (No. studies) Interven(on (Improvement) Fewtrell et al.(2005) Clasen et al.(2006) Waddington et al (2009) Source or POU 0.69 ( ) (15) 0.57 ( ) (38) 0.58 ( ) (31) Source 0.89 ( ) (3) 0.73 ( ) (6) 0.79 ( ) (3) Point- of- use) 0.65 ( ) (12) 0.53 ( ) (32) 0.56 ( ) (28) Fewtrell L, Kaufmann RB, Kay D, Enanoria W, Haller L, Colford JM Jr. Water, sanita0on, and hygiene interven0ons to reduce diarrhoea in less developed countries: a systema0c review and meta- analysis. Lancet Infect Dis Jan;5(1): Clasen T, Schmidt WP, Rabie T, Roberts I, Cairncross S. Interven0ons to improve water quality for preven0ng diarrhoea: systema0c review and meta- analysis. BMJ Apr 14;334(7597):782. Waddington, H., Snilstveit, B., White, H., & Fewtrell, Lorna. (2009). Water, sanita+on and hygiene interven+ons to combat childhood diarrhoea in developing countries: The Interna0onal Ini0a0ve for Impact Evalua0on (3ie).

4 Schmidt & Cairncross 2009

5

6 Engell & Lim 2013 Only the abstract has been published; accordingly, the methods are not publicly available. Described as an update of previous reviews by Fewtrell et al. (2005), Clasen et al. 2006, Cairncross et al. (2010), Waddington et al. (2009), but elects to ignore open trials in favour of blinded trials Departs from previous GBD studies that did not rely solely on blinded studies (Kirchhoff 1985, Aus0n 1993)

7 Engell & Lim 2013 we found no difference in point- of- use interven0ons when blinding was taken into account (p=0 08). (Engell & Lim, submiled) We did not find a significantly improved effect of water quality interven0ons, consistent with the findings reported by Cairncross and colleagues which showed that masked point- of- use water quality interven0ons did not have a significant effect on self- reported diarrhoea. (Lim 2012).

8

9 Wolf et al Methods 5 data bases, English and French publica0ons Includes observa0onal studies as well as RCTs and non- randomized RCTs Excludes studies where interven0on achieved low levels of coverage or use (<20%) Meta- regression to explore source (community vs household connec0on), point- of- use (filtra0on, chlorina0on, solar disinfec0on), safe storage, water supplies (piped vs unimproved), length of follow up water supplies Adjust for non- blinding

10 Hunter 2009 Adjus0ng for Blinding

11 Wolf et al. Meta- regression results for water interven0ons, not adjusted for non- blinding * con0nuous and safe water quality, based on limited evidence (Hunter et al. 2010) for quality improvements on piped and should therefore be considered with cau0on. Figures are rela0ve risks (and 95% confidence intervals) and those in italics relate to addi0onal safe storage.

12 Wolf et al. Meta- regression results for water interven0ons, not adjusted for non- blinding Meta- regression results for water interven0ons, adjusted for non- blinding * con0nuous and safe water quality, based on limited evidence (Hunter et al. 2010) for quality improvements on piped and should therefore be considered with cau0on. Figures are rela0ve risks (and 95% confidence intervals) and those in italics relate to addi0onal safe storage.

13

14 Clasen et al. (2014 update) Methods RCTs and quasi- RCTs only; no observa0onal studies All languages, published and unpublished Does not exclude low- compliance studies Assessment of methodological quality using GRADE Es0mates for all ages and <5s Sub- grouping by interven0on point, HWT type, compliance, ambient water quality, ambient water supply and sanita0on, combined (e.g.,storage vessel, hygiene, sanita0on, etc.), length of follow up, country income level

15 Clasen et al. (2014 update) Results Fity- six trials (with mul0ple arms, including 67 independent comparisons covering over 98,000 par0cipants) met the inclusion criteria. Nine blinded trials (10 comparisons) Differences in seungs, interven0ons, study designs, outcomes and other methods limited the comparability of results and the probity of pooling by meta- analysis.

16 Es0mate of Effect by Interven0on Point and Type Outcome: Diarrhoea: all ages Relative Risk (95% CI) No. of Participants (No. study comparisons) Quality of evidence (GRADE) Source or household treatment 0.62 (0.53 to 0.72) (67) ΟΟ LOW Source treatment 0.74 (0.54 to 1.00) (8) ΟΟ LOW Household treatment 0.60 (0.50 to 0.73) (59) ΟΟ LOW Household treatment: chlorination 0.70 (0.60 to 0.81) (24) ΟΟ LOW Household treatment: filtration 0.52 (0.45 to 0.60) (20) Ο MODERATE Household treatment: flocculation & 0.69 (0.58 to 0.82) (7) ΟΟΟ VERY LOW disinfection Household treatment: SODIS 0.68 (0.53 to 0.89) 4015 (6) ΟΟΟ VERY LOW

17 Es0mate of Effect, all ages and <5s Interven0on Point and Type Intervention point or type Relative risk (95%CI) ALL AGES <5s Source or household treatment 0.62 (0.53 to 0.72) 0.63 (0.51 to 0.77) Source treatment 0.74 (0.54 to 1.00) 0.90 (0.74 to 1.10) Household treatment 0.60 (0.50 to 0.73) 0.61 (0.49 to 0.77) Household treatment: chlorination 0.70 (0.60 to 0.81) 0.74 (0.62 to 0.88) Household treatment: filtration 0.52 (0.45 to 0.60) 0.57 (0.47 to 0.68) Household treatment: flocculation & disinfection 0.69 (0.58 to 0.82) 0.52 (0.20 to 1.37) Household treatment: SODIS 0.68 (0.53 to 0.89) 0.55 (0.34 to 0.91)

18 Compliance and Water/Sanita0on Condi0ons Outcome: Diarrhoea: all ages Relative risk (95% CI) No. of Participants (No. study comparisons) Quality of evidence (GRADE) Compliance with intervention 50% compliance 0.80 (0.71 to 0.90) (14) ΟΟ LOW 51-85% compliance 0.61 (0.37 to 1.00) (17) ΟΟΟ VERY LOW % compliance 0.56 (0.47 to 0.65) (14) Ο MODERATE Water quantity Sufficient water quantity 0.77 (0.69 to 0.86) (17) ΟΟ LOW Insufficient water quantity 0.49 (0.50 to 1.56) (5) ΟΟΟ VERY LOW Water supply level Improved water supply 0.63 (0.53 to 0.74) (21) ΟΟ LOW Unimproved water supply 0.64 (0.53 to 0.78) (44) ΟΟ LOW Sanitation level Improved sanitation 0.50 (0.33 to 0.77) (21) ΟΟ LOW Unimproved sanitation 0.66 (0.57 to 0.77) (22) ΟΟ LOW

19 Outcome: Diarrhoea: all ages Simple vs. Compound, Country Level and Follow up Relative effect (95% CI) No. of Participants (No. study comparisons) Quality of evidence (GRADE) Simple and compound interventions Water quality only RR 0.67 (0.57 o 0.78) (23) ΟΟ LOW Water quality + hygiene promotion RR 0.66 (0.55 to 0.79) (18) ΟΟ LOW Water quality + improved storage RR 0.55 (0.42 to 0.74) (34) ΟΟ LOW Water quality + sanitation RR 0.68 (0.56 to 0.84) (4) ΟΟ LOW Water quality + improved water supply RR 0.66 (0.50 to 0.88) (10) ΟΟ LOW Country income level High RR 0.77 (0.63 to 0.96) 2719 (5) ΟΟ LOW Upper middle RR 0.58 (0.42 to 0.81) 9226 (7) ΟΟΟ VERY LOW Lower middle RR 0.61 (0.52 to 0.72) (22) ΟΟ LOW Low RR 0.64 (0.50 to 0.82) (34) ΟΟΟ VERY LOW Length of follow-up 3 months follow-up RR 0.43 (0.16 to 1.17) (7) ΟΟΟ VERY LOW >3-6 months follow-up RR 0.60 (0.51 to 0.69) (22) ΟΟ LOW >6-12 months follow-up RR 0.64 (0.56 to 0.74) (23) ΟΟ LOW >13 months follow-up RR 0.79 (0.64 to 0.96) (15) ΟΟ LOW

20 Safe Storage May Maler less for Chlorine Interven0ons POU Interven(on (51 comparisons) Chlorine Filtra0on Floccula0on and disinfec0on RR (95%CI, number of studies) Main analysis Studies with safe storage Studies without safe storage 0.70 (0.60 to 0.81, n=24) 0.56 (0.49 to 0.65, n=20) 0.48 (0.20 to 1.16, n=7) 0.67 (0.53 to 0.84, n=13) 0.51 (0.43 to 0.61, n= (0.14 to 1.08, n=2) 0.75 (0.64 to 0.89, n=11) 0.76 (0.66 to 0.88 n=8) 0.81 (0.69 to 0.95, n=5)

21

22 Issues with blinded studies Study Risk from ambient Compliance water quality Colford 2002 Very Low (USA piped) High (Sham in- line filter) Colford 2005 Very Low (USA piped) High (Sham in- line filter) Colford 2009 Very Low (USA piped) High (Sham in- line filter) Other issues Rodrigo 2011 Low? (untreated rainwater Australia) High (Sham in- line filter) Did not report on water quality Jain 2009 Low (median 1 CFU EC/ 100ml in control group at end of study) High (RFC) Control group received jerry can; only 12 week follow up Kirchhoff 1985 Very high (mean FC/dl) Not reported Only 112 persons from 16 HH; 18 week trial Aus0n 1993 High (1871 FC/100ml) Low ( 50% to 60% ) No test of blinding; not peer reviewed Boisson 2010 High (75% of samples >1000 TTC/100ml) High, but 73% of adults and 95% of children drank from Placebo removed >90% of TTC in control arm Boisson 2013 Moderate (mean 122 TTC/100ml) untreated sources Low and inconsistent (32% of samples posi0ve for RFC)

23 Brown and Clasen 2012 Consistent Use

24 Adjus0ng for Non- Blinding Not adjusted Adjusted N RR 95% CI RR 95% CI Source or POU (0.58, 0.67) 0.73 (0.66, 0.79) Source (0.56, 0.98) 0.81 (0.62, 1.05) POU (0.57, 0.66) 0.71 (0.64, 0.78) POU- chlorine (0.61, 0.79) 0.77 (0.67, 0.87) POU- filtra0on (0.51, 0.62) 0.66 (0.58, 0.74) POU- flocc (0.34, 0.78) 0.60 (0.34, 1.01) POU- SODIS (0.52, 0.96) 0.78 (0.58, 1.03)

25 Conclusions Interven0ons to improve the microbiological quality of drinking water are effec0ve in preven0ng diarrhoea both for popula0ons of all ages and children under five years old. Community- level improvements in water supplies such as protected wells were borderline protec0ve (RR 0.74, 95% CI 0.54 to 1.0, 8 comparisons). This es0mate does not include household connec0ons for which there were no eligible studies. Point- of- use interven0ons were also protec0ve (RR 0.60, 95% CI 0.50 to 0.73, 59 comparisons), but the reported effect may be exaggerated due to bias.

26 Conclusions Ater adjus0ng for non- blinding, POU chlorina0on (RR 0.77, 95% CI 0.67 to 0.87) and filtra0on (RR 0.66, 95% CI 0.58 to 0.74) remain protec0ve; other POU methods do not Effec0veness was posi0vely associated with compliance Interven0ons were effec0ve even in seungs without improved water supplies or sanita0on. A need for longer trials with objec0ve outcomes, and under- evaluated interven0ons, especially boiling and household connec0ons)

27 Acknowledgements K. Alexander, Emory University S. Boisson, WHO R. Peletz, Aquaya Ins0tute H. Chang, Emory Univeristy S. Cairncross, LSHTM