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HTN: Diet Patterns (2015)

Citation:

Kirpizidis H, Stavrati A, Geleris P. Assessment of quality of life in a randomized clinical trial of candesartan only or in combination with DASH diet for hypertensive patients. J Cardiol. 2005; 46(5): 177-182.

PubMed ID: 16320974
 
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To compare the effects of an angiotensin II type I receptor inhibitor, Candesartan, singly or in combination with a reducing sodium diet, the DASH diet, on the quality of life (QOL) in outpatients with hypertension.
Inclusion Criteria:
  • Hypertensive outpatients from 14 anti-hypertensive centers were enrolled
  • Hypertension was defined as seated diastolic blood pressure ranging from 95mm Hg to 110mm Hg
  • Provided written informed consent.
Exclusion Criteria:
  • Patients with heart failure, renal or hepatic disease
  • Patients with systolic blood pressure higher than 220mm Hg or diastolic blood pressure higher than 110mm Hg during the washout period.
Description of Study Protocol:

Recruitment

Patients were recruited from 14 anti-hypertensive centers.

Design

Randomized controlled trial.

Statistical Analysis

  • Data are presented as mean±SE
  • Comparisons between baseline and end treatment measurements were analyzed by the paired T-test
  • A value of P<0.05 was considered statistically significant
  • ANOVA was used to assess the effect of treatments on QOL dimension scores.

 

Data Collection Summary:

Timing of Measurements

  • QOL was measured at baseline and 16 weeks
  • BP was measured at baseline, eight weeks and 16 weeks.

Dependent Variables

  • Blood pressure:
    • Blood pressure measurements were taken with a standard mercury sphymanometer by the same physician of each anti-hypertensive center after 10 minutes rest in a sitting position
    • Two seated measurements were taken within a five-minute period and the mean of the two measurements was used.
  • Quality of life (QOL) in patients with hypertension (measured by the SSAP):
    • The questionnaire was designed to survey health-related QOL issues for clinical research
    • The 42 questions are associated with general and mental health, body pain, vitality, physical and emotional plus social functioning
    • The self-administered questionnaire uses a 10-grade scale
    • The higher the score, the better the patient
    • The validity, reliability and utility of the questionnaire have been established across various clinical studies.

Independent Variables

Candesartan vs. Candesartan plus DASH diet:
  • Patients in the Candesartan group took an 8mg Candesartan tablet in the morning, the dosage was increased to 16mg for the next eight weeks if the diastolic blood pressure was 90mm Hg or higher after the first phase of treatment
  • Patients on the DASH diet were given a weekly menu that allowed a daily sodium level of either 2,400mg or by making the noted changes 1,500mg
  • Life study modification, such as smoking cessation and training, was encouraged as complimentary measures to both treatments for all patients.
Description of Actual Data Sample:
  • Initial N: N=201
  • Attrition (final N): N=201 [102 in the Candesartan group, (33.3% female) vs. 99 in the Candesartan plus DASH group (31.3% female)]
  • Age: Mean age in the Candesartan group is 53.5 years. vs. 54.1 years in the Candesartan plus DASH group.

Other Relevant Demographics

  • Mean baseline SBP in the Candesartan group 149.3±5mm Hg.8 vs, 148.7±6.2mm Hg in the Candesartan plus DASH group. Mean baseline DBP in the Candesartan group 98.9±3.6mm Hg vs. 99.1±4.1mm Hg in the Candesartan plus DASH group

Location

Greece.

Summary of Results:

Key Findings

  • Resting blood pressures were significantly reduced by the combination of Candesartan and DASH diet (P<0.005)
  • There were no significant differences comparing the two treatment groups
  • DBP was normalized in 64.7% of Candesarten-only patients, and in 72.7% of Candesarten plus DASH patients.
Effect of Candesartan vs. Cardesarten plus DASH on BP
 
 
  Candesarten Candesarten
Plus DASH
  Baseline Eight weeks 16 weeks Baseline Eight weeks 16 weeks
SBP (mm Hg) 149.3±8.8 137.4±6.2*  132.3±5.9* 148.7±9.2 133.8±5.5* 127.7±5.1*
DBP (mm Hg) 98.9±4.6 88.7±5.8* 85.4±6.2 99.1±4.9 84.8±6.2* 82.1±5.4*
*Compared to baseline, P<0.001.
 
Other Findings
 
Significant improvement was demonstrated for the mental component, emotional health and vitality scores after 16 weeks of treatment with the combination of Candesartan and DASH diet (P<0.03).
Author Conclusion:
Angiotensin II type 1 receptor blockade with a therapeutic dosage of Candesartan maintains significant control of blood pressure and may improve QOL scores, especially when combined with a reducing sodium diet.
Funding Source:
Industry:
Astra Zeneca
Pharmaceutical/Dietary Supplement Company:
In-Kind support reported by Industry: Yes
Reviewer Comments:
A major strength of this study is that it demonstrated that Candesartan was effective to reduce blood pressure in mild to moderate hypertension.
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
 
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? No
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? No
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) No
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? Yes
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? No
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? No
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes