Diet and Hypertension Management in African Americans With Chronic Kidney Disease

Overview

The purpose of this study is to determine cultural and disease-related barriers and facilitators to following the Dietary Approaches to Stop Hypertension (DASH) dietary pattern among Black Americans with moderate chronic kidney disease (CKD) and test the impact of a behavioral diet counseling intervention on DASH diet adherence, blood pressure, and CKD-relevant outcomes.

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: None (Open Label)
  • Study Primary Completion Date: August 30, 2024

Detailed Description

Excess cardiovascular disease (CVD) mortality among Black Americans with CKD is a significant US public health disparity. Compared to their White counterparts, Blacks develop CKD earlier in life and Blacks with CKD are 3 times more likely to progress to kidney failure necessitating dialysis or kidney transplantation, and are 1.5 times more likely to die prematurely from CVD. Hypertension, which is also more prevalent, more severe, and less often controlled in Blacks with CKD compared to Whites, is a leading cause of CKD and CVD, and a major contributor to the racial disparity in CVD mortality. Thus, improving hypertension in Blacks with CKD could have a profound positive impact on an important minority health issue.

The DASH diet lowers BP and reduces CVD risk in patients with hypertension and has a greater effect on BP in Blacks compared to Whites. However, the effect of the DASH diet on BP in Blacks with CKD has not been established. First, investigators will conduct a qualitative study to identify self-perceived barriers and facilitators of DASH diet adherence among Blacks with moderate CKD. Then, investigators will conduct feasibility, acceptability, and preliminary efficacy testing of a disease-sensitive, culturally-appropriate diet counseling intervention on DASH adherence and blood pressure in Blacks with CKD.

Interventions

  • Behavioral: DASH diet counseling
    • Culturally-appropriate, disease-sensitive counseling intervention to enhance DASH diet adherence in Blacks with CKD compared to standard of care condition

Arms, Groups and Cohorts

  • No Intervention: Qualitative Focus Groups
    • Three to 4 groups of 6-8 participants will be asked semi-structured questions to determine self-perceived sociocultural barriers and facilitators of DASH diet adherence and disease-specific factors that may influence their ability and willingness to follow a DASH-style diet.
  • Experimental: Behavioral Diet Counseling
    • Groups of 4-6 participants will attend 12 weekly dietitian-led counseling sessions and receive coaching on practical strategies to enhance DASH diet adherence and reduce daily sodium intake.
  • Other: Standard of Care
    • Participants will meet one-on-one with the study dietitian for a single 30- minute encounter and be advised to limit daily sodium intake per current clinical practice guidelines for hypertension in patients with CKD. Educational handouts and tip sheets about practical strategies to reduce dietary sodium will be distributed.

Clinical Trial Outcome Measures

Primary Measures

  • Number of different types of self-reported barriers to DASH diet adherence
    • Time Frame: Up to one year
    • Self-reported barriers will be analyzed using 5 stage approach (familiarization; identifying a thematic framework; indexing; charting & mapping, and interpretation) to measure the number of different types of barriers.
  • Number of different types of self-reported facilitating factors to DASH diet adherence
    • Time Frame: Up to one year
    • Self-reported facilitating factors will be analyzed using 5 stage approach (familiarization; identifying a thematic framework; indexing; charting & mapping, and interpretation) to measure the number of different types of facilitating factors.
  • Number of Participants who complete the 12 week intervention program
    • Time Frame: Up to 12 weeks
    • Completion will be measured by the number of group counseling sessions attended by participants randomized to the treatment arm.
  • Number of participants who complete data collection visits
    • Time Frame: Up to 6 months
    • Completion will be measured by the number of randomized participants who provide blood and urine biospecimens, clinic and 24-hour ambulatory blood pressure measurements, and 24-hour dietary recall data during scheduled data collection visits at baseline, 1 month, 3 months, and 6 months.
  • Change in 24-hour mean systolic blood pressure during treatment
    • Time Frame: Baseline to 12 weeks
    • Change will be measured by comparing the 24-hr mean systolic blood pressures (mmHg) obtained at baseline and at 12 weeks (end of treatment.)
  • Change in serum potassium concentration during treatment
    • Time Frame: Baseline to 12 weeks
    • Change will measured by comparing serum potassium concentration levels obtained at baseline and at 12 weeks (end of treatment.)
  • Change in 24 hour urine concentrations of sodium during treatment
    • Time Frame: Baseline to 12 weeks
    • Change will be measured by comparing sodium concentration levels (mmol/24 hr) obtained from 24 hour urine samples collected at baseline and 12 weeks (end of treatment.)
  • Change in 24 hour urine concentrations of potassium during treatment
    • Time Frame: Baseline to 12 weeks
    • Change will be measured by comparing potassium concentration levels (mmol/24 hr) obtained from 24 hour urine samples collected at baseline and 12 weeks (end of treatment.)
  • Change in 24 hour urine concentrations of phosphorus during treatment
    • Time Frame: Baseline to 12 weeks
    • Change will be measured by comparing phosphorus concentration levels (mg/24 hr) obtained from 24 hour urine samples collected at baseline and 12 weeks (end of treatment.)
  • Change in 24 hour urine concentrations of urea nitrogen during treatment
    • Time Frame: Baseline to 12 weeks
    • Change will be measured by comparing phosphorus concentration levels (g/24 hr) obtained from 24 hour urine samples collected at baseline and 12 weeks (end of treatment.)

Secondary Measures

  • Change in clinic systolic blood pressure during treatment
    • Time Frame: Baseline to 12 weeks
    • Change will be measured by comparing clinic systolic blood pressures (mgHH) obtained at baseline and at 12 weeks (end of treatment.)
  • Change in body weight during treatment
    • Time Frame: Baseline to 12 weeks
    • Change will be measured by comparing body weights (kg.) obtained at baseline and at 12 weeks (end of treatment.)
  • Change in 24-hour mean systolic blood pressure 3-months post-treatment.
    • Time Frame: 12 weeks to 24 weeks
    • Change will be measured by comparing the 24-hour mean systolic blood pressures (mmHg) obtained at 12 weeks (end of treatment) and at 24 weeks (3-months post-treatment.)
  • Change in body weight 3 months after intervention
    • Time Frame: 12 weeks to 24 weeks
    • Change will be measured by comparing body weights (kg.) obtained at 12 weeks (end of treatment) and at 24 weeks (3-months post-treatment.)
  • Number of participants who sustained their end of treatment DASH diet adherence scores for 3 months after intervention.
    • Time Frame: 12 weeks to 24 weeks
    • Sustained DASH diet scores will be measured by comparing scores derived from 24-hour dietary recall data obtained at 12 weeks (end of treatment) and at 24 weeks (3-months post-treatment.)

Participating in This Clinical Trial

Inclusion Criteria

  • Black race (self-identified)
  • CKD defined as an eGFR of 20-59 ml/min/1.73m2
  • CKD self-awareness

Exclusion Criteria

  • History of kidney transplant
  • Lack of English language proficiency
  • Pregnant or breast-feeding
  • High risk for developing hyperkalemia defined as insulin-dependent diabetes mellitus, poor blood glucose control (A1C >10), baseline serum potassium ≥4.8 mg/dl, and serum bicarbonate <18 mg/dl, incidence of hyperkalemia 6 months preceding enrollment defined as serum potassium greater than 5.1 mg/dl
  • Risk for hypotension or severe hypertension (SBP <120 or ≥180 or DBP ≥110 mm Hg)

Gender Eligibility: All

Minimum Age: 21 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Duke University
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Crystal Tyson, M.D., Principal Investigator, Duke University
  • Overall Contact(s)
    • Cynthia Redd, M.Ed, 919-684-9545, cindy.redd@duke.edu

References

Tyson CC, Davenport CA, Lin PH, Scialla JJ, Hall R, Diamantidis CJ, Lunyera J, Bhavsar N, Rebholz CM, Pendergast J, Boulware LE, Svetkey LP. DASH Diet and Blood Pressure among Black Americans with and without Chronic Kidney Disease: the Jackson Heart Study. Am J Hypertens. 2019 Jun 11. pii: hpz090. doi: 10.1093/ajh/hpz090. [Epub ahead of print]

Tyson CC, Barnhart H, Sapp S, Poon V, Lin PH, Svetkey LP. Ambulatory blood pressure in the dash diet trial: Effects of race and albuminuria. J Clin Hypertens (Greenwich). 2018 Feb;20(2):308-314. doi: 10.1111/jch.13170. Epub 2018 Jan 31.

Tyson CC, Lin PH, Corsino L, Batch BC, Allen J, Sapp S, Barnhart H, Nwankwo C, Burroughs J, Svetkey LP. Short-term effects of the DASH diet in adults with moderate chronic kidney disease: a pilot feeding study. Clin Kidney J. 2016 Aug;9(4):592-8. doi: 10.1093/ckj/sfw046. Epub 2016 Jun 5.

Tyson CC, Kuchibhatla M, Patel UD, Pun PH, Chang A, Nwankwo C, Joseph MA, Svetkey LP. Impact of Kidney Function on Effects of the Dietary Approaches to Stop Hypertension (Dash) Diet. J Hypertens (Los Angel). 2014;3. pii: 1000168.

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