title: Control of Blood Pressure and Risk Attenuation: Post Trial Follow-Up of Randomized Groups.
abstract: BACKGROUND
  Evidence on long term effectiveness of public health strategies for lowering blood pressure (BP) is scarce. In the Control of Blood Pressure and Risk Attenuation (COBRA) Trial, a 2 x 2 factorial, cluster randomized controlled trial, the combined home health education (HHE) and trained general practitioner (GP) intervention delivered over 2 years was more effective than no intervention (usual care) in lowering systolic BP among adults with hypertension in urban Pakistan. However, it was not clear whether the effect would be sustained after the cessation of intervention. We conducted 7 years follow-up inclusive of 5 years of post intervention period of COBRA trial participants to assess the effectiveness of the interventions on BP during extended follow-up.
  
  
  METHODS
  A total of 1341 individuals 40 years or older with hypertension (systolic BP 140 mm Hg or greater, diastolic BP 90 mm Hg or greater, or already receiving treatment) were followed by trained research staff masked to randomization status. BP was measured thrice with a calibrated automated device (Omron HEM-737 IntelliSense) in the sitting position after 5 minutes of rest. BP measurements were repeated after two weeks. Generalized estimating equations (GEE) were used to analyze the primary outcome of change in systolic BP from baseline to 7- year follow-up. The multivariable model was adjusted for clustering, age at baseline, sex, baseline systolic and diastolic BP, and presence of diabetes.
  
  
  RESULTS
  After 7 years of follow-up, systolic BP levels among those randomised to combined HHE plus trained GP intervention were significantly lower (2.1 [4.1-0.1] mm Hg) compared to those randomised to usual care, (P = 0.04). Participants receiving the combined intervention compared to usual care had a greater reduction in LDL-cholesterol (2.7 [4.8 to 0.6] mg/dl.
  
  
  CONCLUSIONS
  The benefit in systolic BP reduction observed in the original cohort assigned to the combined intervention was attenuated but still evident at 7- year follow-up. These findings highlight the potential for scaling-up simple strategies for cardiovascular risk reduction in low- and middle- income countries.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT00327574.
authors.affiliation: Program in Health Services & Systems Research, Duke-NUS Graduate Medical School, Singapore, Singapore.|Department of Community Health Science, Aga Khan University, Karachi, Pakistan.|Section of Nephrology, Department of Medicine, Aga Khan University, Karachi, Pakistan.
authors.forename: Tazeen H
authors.initials: TH
authors.lastname: Jafar
authors.affiliation: Department of Community Health Science, Aga Khan University, Karachi, Pakistan.
authors.forename: Imtiaz
authors.initials: I
authors.lastname: Jehan
authors.affiliation: Program in Health Services & Systems Research, Duke-NUS Graduate Medical School, Singapore, Singapore.
authors.forename: Feng
authors.initials: F
authors.lastname: Liang
authors.affiliation: Centre for Quantitative Medicine, Office of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore, Singapore.
authors.forename: Sylvaine
authors.initials: S
authors.lastname: Barbier
authors.affiliation: Department of Community Health Science, Aga Khan University, Karachi, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Islam
authors.affiliation: Department of Community Health Science, Aga Khan University, Karachi, Pakistan.
authors.forename: Rasool
authors.initials: R
authors.lastname: Bux
authors.affiliation: Section of Cardiology, Department of Medicine, Aga Khan University, Karachi, Pakistan.
authors.forename: Aamir Hameed
authors.initials: AH
authors.lastname: Khan
authors.affiliation: Centre for Quantitative Medicine, Office of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore, Singapore.
authors.forename: Nivedita
authors.initials: N
authors.lastname: Nadkarni
authors.affiliation: National Heart & Lung Institute, Imperial College, London, United Kingdom.
authors.forename: Neil
authors.initials: N
authors.lastname: Poulter
authors.affiliation: Institute of Cardiovascular Sciences, University College, London, United Kingdom.
authors.forename: Nish
authors.initials: N
authors.lastname: Chaturvedi
authors.affiliation: Department of Non-communicable Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom.
authors.forename: Shah
authors.initials: S
authors.lastname: Ebrahim
mesh_terms: D004502:Education, Medical, Continuing / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D058005:General Practitioners / Q000193:education; D006266:Health Education / Q000379:methods; D006801:Humans; D006973:Hypertension / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D040242:Risk Reduction Behavior; D016896:Treatment Outcome