title: Impact evaluation of a community-based intervention for prevention of cardiovascular diseases in the slums of Nairobi: the SCALE-UP study.
abstract: BACKGROUND
  A combination of increasing urbanization, behaviour change, and lack of health services in slums put the urban poor specifically at risk of cardiovascular disease (CVD). This study aimed to evaluate the impact of a community-based CVD prevention intervention on blood pressure (BP) and other CVD risk factors in a slum setting in Nairobi, Kenya.
  
  
  METHODS
  Prospective intervention study includes awareness campaigns, household visits for screening, and referral and treatment of people with hypertension. The primary outcome was overall change in mean systolic blood pressure (SBP), while secondary outcomes were changes in awareness of hypertension and other CVD risk factors. We evaluated the intervention's impact through consecutive cross-sectional surveys at baseline and after 18 months, comparing outcomes of intervention and control group, through a difference-in-difference method.
  
  
  RESULTS
  We screened 1,531 and 1,233 participants in the intervention and control sites. We observed a significant reduction in mean SBP when comparing before and after measurements in both intervention and control groups, -2.75 mmHg (95% CI -4.33 to -1.18, p=0.001) and -1.67 mmHg (95% CI -3.17 to -0.17, p=0.029), respectively. Among people with hypertension at baseline, SBP was reduced by -14.82 mmHg (95% CI -18.04 to -11.61, p<0.001) in the intervention and -14.05 (95% CI -17.71 to -10.38, p<0.001) at the control site. However, comparing these two groups, we found no difference in changes in mean SBP or hypertension prevalence.
  
  
  CONCLUSIONS
  We found significant declines in SBP over time in both intervention and control groups. However, we found no additional effect of a community-based intervention involving awareness campaigns, screening, referral, and treatment. Possible explanations include the beneficial effect of baseline measurements in the control group on behaviour and related BP levels, and the limited success of treatment and suboptimal adherence in the intervention group.
authors.affiliation: African Population and Health Research Center, Nairobi, Kenya.|Department of Global Health, Academic Medical Center, University of Amsterdam and Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands; svijver@aphrc.org.
authors.forename: Steven
authors.initials: S
authors.lastname: van de Vijver
authors.affiliation: African Population and Health Research Center, Nairobi, Kenya.|Department of Global Health, Academic Medical Center, University of Amsterdam and Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands.
authors.forename: Samuel Oji
authors.initials: SO
authors.lastname: Oti
authors.affiliation: Department of Global Health, Academic Medical Center, University of Amsterdam and Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands.|Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Gabriela B
authors.initials: GB
authors.lastname: Gomez
authors.affiliation: Department of Public Health, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Charles
authors.initials: C
authors.lastname: Agyemang
authors.affiliation: African Population and Health Research Center, Nairobi, Kenya.
authors.forename: Thaddaeus
authors.initials: T
authors.lastname: Egondi
authors.affiliation: Department of Family Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Eric
authors.initials: E
authors.lastname: Moll van Charante
authors.affiliation: Department of Public Health, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.|Departments of Vascular and Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Lizzy M
authors.initials: LM
authors.lastname: Brewster
authors.affiliation: Department of Global Health, Academic Medical Center, University of Amsterdam and Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands.|Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Catherine
authors.initials: C
authors.lastname: Hankins
authors.affiliation: Amsterdam Institute for International Development (AIID), Faculty of Economics and Business Administration, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
authors.forename: Zlata
authors.initials: Z
authors.lastname: Tanovic
authors.affiliation: African Population and Health Research Center, Nairobi, Kenya.
authors.forename: Alex
authors.initials: A
authors.lastname: Ezeh
authors.affiliation: African Population and Health Research Center, Nairobi, Kenya.
authors.forename: Catherine
authors.initials: C
authors.lastname: Kyobutungi
authors.affiliation: Department of Public Health, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Karien
authors.initials: K
authors.lastname: Stronks
mesh_terms: D000328:Adult; D001795:Blood Pressure Determination; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000517:prevention & control*; D003430:Cross-Sectional Studies; D005260:Female; D006293:Health Promotion / Q000379:methods*; D006801:Humans; D006973:Hypertension / Q000453:epidemiology / Q000517:prevention & control*; D007630:Kenya / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011204:Poverty Areas; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors
keywords: Kenya; awareness; blood pressure; cardiovascular disease; hypertension; prevention; slum; treatment; urban poor