HTN: Minerals (2007)
- Essential HTN
- SBP above 140mm Hg or DBP above 90mm Hg at end of one-week placebo run-in period.
- Recruitment: Patients with essential HTN in the Shaanxi district; methods not described
- Design: Randomized controlled trial
- Intervention: Potassium magnesium supplementation or lacidipine for four weeks.
Statistical Analysis
- Descriptive data expressed as mean±SD
- The clinical variables, biochemical measurements and arterial compliance between the two groups were compared by an unpaired Student's T-test
- After the treatment, blood pressure and arterial compliance were compared with the baseline by the paired T-test
- Statistical significance was inferred at a two-tailed P-value of <0.05.
Timing of Measurements
Before and after the four weeks, blood pressure, blood samples, large arterial compliance and small arterial compliance were measured.
Dependent Variables
- Large arterial compliance and small arterial compliance measured by CVProfilor DO-2020 CardioVascular Profiling System, showed good reproducibility in Chinese subjects
- Blood pressure
- Blood samples evaluated for serum total and HDL cholesterol, triglycerides
- Whole blood glucose measured with one-touch test strips
- LDL calculated through Friedewald formula.
Independent Variables
- Magnesium potassium supplementation (70.8mg magnesium per day, 217.2mg potassium per day) for four weeks
- Lacidipine (four mg per day) for four weeks
- Patients instructed to follow usual diet.
Initial N
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133 patients with essential HTN
-
147 healthy subjects enrolled
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67 of the 133 agreed to receive further treatment.
Attrition (Final N)
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35 subjects received potassium magnesium supplementation (10 males, 25 females)
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32 received lacidipine (nine males, 23 females)
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147 healthy subjects (68 males, 79 females).
Age
Potassium magnesium: Mean, 58±7 years (range 41-70 years)
Lacidipine: Mean, 56±8 years, range 39-70 years
Controls: Mean, 54±9 years (range 39-75 years).
Ethnicity
Not mentioned.
Other Relevant Demographics
Healthy subjects matched for age, sex and body surface area.
Anthropometrics
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There were no differences in the prescribed anti-hypertensive medications between the two groups before the one-week placebo run-in period
No significant differences in clinical characteristics, metabolic plasma parameters, pre-treatment BP or arterial compliance values were noted between the two treatment groups.
Location
Shaanxi, China.
Lacidipine - Before | Lacidipine - After | K/Mg - Before | K/Mg - After | |
SBP (mm Hg) | 148.73±19.21 | 135.47±17.55, P<0.01 | 142.36±17.14 | 134.53±12.69, P<0.01 |
DBP (mm Hg) |
86.06±13.09 |
79.73±10.53, P<0.01 |
82.46±9.04 |
78.79±7.96, P<0.05 |
MAP (mm Hg) | 110.38±14.03 | 101.73±12.64, P<0.01 | 106.03±11.73 | 99.61±9.51, P<0.01 |
PP (mm Hg) | 61.55±12.46 | 55.73±10.01, P<0.01 | 59.90±14.40 | 55.73±9.21, P<0.05 |
SVR | 2038±359 | 1795±304, p <0.01 | 2058±405 | 1717±262, P<0.01 |
HR (beats/min) | 74.11±9.23 | 71.05±10.76 | 67.99±9.03 | 68.34±9.98 |
Large Arterial Compliance (ml/mm Hg x 10) | 10.413±3.680 | 12.503±4.871, P<0.01 | 12.961±4.032 | 13.571±4.157 |
Small Arterial Compliance (ml/mm Hg x 100) |
3.412±1.526 |
4.033±1.807, P<0.01 |
3.241±1.569 |
3.897±2.040, P<0.05 |
Other Findings
- It was found that arterial compliance was significantly lower in patients with essential HTN, compared with healthy subjects
- Large arterial compliance: 12.53±0.33 vs. 15.63±0.30ml per mm Hg x 10, P<0.01
- Small arterial compliance: 3.79±0.17 vs. 5.69±0.25ml per mm Hg x 100, P<0.01.
- On lacidipine, SBP and DBP decreased 13.27±1.76mm Hg and 6.33±1.55mm Hg. Large arterial compliance increased 25.05%±4.49% and small arterial compliance increased 34.50±7.40%.
- On potassium magnesium supplementation, SBP and DBP decreased 7.83±1.87mm Hg and 3.67±1.03mm Hg. Large arterial compliance increased 12.44%±4.43% and small arterial compliance increased 45.25%±6.67%.
- Decreases in systemic vascular resistance by 11.9% for lacidipine and 16.6% for potassium magnesium supplementation (P<0.01) were seen between the drug-induced changes
- The changes in SBP and DBP did not differ significantly between the different drug therapies, but the post-treatment pressures differed significantly from pre-treatment (P<0.01).
- Both large and small arterial compliance were decreased in essential HTN patients
- Magnesium and potassium supplementation show an improvement in small arterial compliance mostly, while lacidipine improved large arterial compliance significantly.
- Recruitment methods not well-defined and subjects self-selected, based on agreement to further treatment
- Validity of CVProfilor measurements is questionable
- Compliance and dietary intake not assessed.
Quality Criteria Checklist: Primary Research
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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? | ??? | |
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? | ??? | |
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) | ??? | |
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? | ??? | |
4.1. | Were follow-up methods described and the same for all groups? | ??? | |
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%.) | ??? | |
4.3. | Were all enrolled subjects/patients (in the original sample) accounted for? | Yes | |
4.4. | Were reasons for withdrawals similar across groups? | ??? | |
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? | Yes | |
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.) | Yes | |
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? | No | |
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? | ??? | |
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? | ??? | |
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? | No | |
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)? | N/A | |
8.5. | Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? | N/A | |
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? | N/A | |
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 | |