title: Predictors of participant adherence and retention in the African American Study of Kidney Disease and Hypertension.
abstract: The African American Study of Kidney Disease and Hypertension (AASK) was conducted over a 7-year period at 21 clinical centers across the United States to investigate whether one of two levels of blood pressure control and/or one of three classes of antihypertensive medications was more effective at slowing the rate of renal disease in African Americans with renal insufficiency presumed secondary to hypertension. Analysis at the end of the study revealed an overall participant retention rate of 90% (still alive and not on dialysis); defined as having had at least one 125I-iothalamate GFR, the primary data collection element, measured in the final year of the study. Adherence, defined as not missing 3 consecutive protocol visits (6 months) during the study, was 77%. Adherence to protocol visits showed that participants assigned to a low blood pressure goal (mean arterial pressure [MAP] of 92 mm/Hg or lower) had a 30% (95% CI, 9%-45%) lower risk of nonadherence as compared to those assigned to the usual goal [MAP of 102-107] (p = 0.006). No statistically significant difference was observed between randomized drug assignments. Higher baseline systolic (p = 0.0001) and diastolic (p = 0.007) blood pressures were associated with a higher risk of nonadherence. Declining to provide an annual income is associated with a higher risk of nonadherence compared to those with incomes of $15,000 or higher (p = 0.04). In discussing the identifying factors that may predict nonadherence and the strategies that assisted in improving adherence and retention, this article offers insights for researchers in achieving high levels of participation in long-term clinical studies.
authors.affiliation: Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Deborah
authors.initials: D
authors.lastname: Brooks
authors.forename: Jeanne
authors.initials: J
authors.lastname: Charleston
authors.forename: Donna
authors.initials: D
authors.lastname: Dowie
authors.forename: Avril
authors.initials: A
authors.lastname: Gabriel
authors.forename: Yvette Baxter
authors.initials: YB
authors.lastname: Hall
authors.forename: Leena
authors.initials: L
authors.lastname: Hiremath
authors.forename: Tammy
authors.initials: T
authors.lastname: Lightfoot
authors.forename: Mohammed
authors.initials: M
authors.lastname: Sika
authors.forename: Winifred C
authors.initials: WC
authors.lastname: Smith
authors.forename: Xuelei
authors.initials: X
authors.lastname: Wang
mesh_terms: D001741:Black or African American / Q000208:ethnology* / Q000706:statistics & numerical data; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001794:Blood Pressure; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000208:ethnology* / Q000209:etiology / Q000517:prevention & control; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000208:ethnology* / Q000209:etiology / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D015404:Nursing Methodology Research; D010349:Patient Compliance / Q000208:ethnology* / Q000706:statistics & numerical data; D010352:Patient Dropouts / Q000523:psychology* / Q000706:statistics & numerical data; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology
chemical_list: D000959:Antihypertensive Agents