title: Designing and evaluating health systems level hypertension control interventions for African-Americans: lessons from a pooled analysis of three cluster randomized trials.
abstract: OBJECTIVE
  African-Americans (AAs) have a high prevalence of hypertension and their blood pressure (BP) control on treatment still lags behind other groups. In 2004, NHLBI funded five projects that aimed to evaluate clinically feasible interventions to effect changes in medical care delivery leading to an increased proportion of AA patients with controlled BP. Three of the groups performed a pooled analysis of trial results to determine: 1) the magnitude of the combined intervention effect; and 2) how the pooled results could inform the methodology for future health-system level BP interventions.
  
  
  METHODS
  Using a cluster randomized design, the trials enrolled AAs with uncontrolled hypertension to test interventions targeting a combination of patient and clinician behaviors. The 12-month Systolic BP (SBP) and Diastolic BP (DBP) effects of intervention or control cluster assignment were assessed using mixed effects longitudinal regression modeling.
  
  
  RESULTS
  2,015 patients representing 352 clusters participated across the three trials. Pooled BP slopes followed a quadratic pattern, with an initial decline, followed by a rise toward baseline, and did not differ significantly between intervention and control clusters: SBP linear coefficient = -2.60±0.21 mmHg per month, p<0.001; quadratic coefficient = 0.167± 0.02 mmHg/month, p<0.001; group by time interaction group by time group x linear time coefficient=0.145 ± 0.293, p=0.622; group x quadratic time coefficient= -0.017 ± 0.026, p=0.525). RESULTS were similar for DBP. The individual sites did not have significant intervention effects when analyzed separately.
  
  
  CONCLUSIONS
  Investigators planning behavioral trials to improve BP control in health systems serving AAs should plan for small effect sizes and employ a "run-in" period in which BP can be expected to improve in both experimental and control clusters.
authors: Clinical Directors Network, Inc. (CDN), New York, NY 10018; Department of Epidemiology and Population Health, Albert Einstein College of Medicine of Yeshiva University/ Montefiore Medical Center, Bronx, NY 10461. vpavlik@bcm.edu.
authors: Valory N
authors: VN
authors: Pavlik
authors: Wenyaw
authors: W
authors: Chan
authors: David J
authors: DJ
authors: Hyman
authors: Penny
authors: P
authors: Feldman
authors: Gbenga
authors: G
authors: Ogedegbe
authors: Joseph E
authors: JE
authors: Schwartz
authors: Margaret
authors: M
authors: McDonald
authors: Paula
authors: P
authors: Einhorn
authors: Jonathan N
authors: JN
authors: Tobin
mesh_terms: D000328:Adult; D001741:Black or African American; D000368:Aged; D003695:Delivery of Health Care / Q000379:methods / Q000592:standards*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009518:New York; D016032:Randomized Controlled Trials as Topic; D013781:Texas