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Artichoke leaf extract for treating hypercholesterolaemia

  1. Barbara Wider1,*,
  2. Max H Pittler2,
  3. Joanna Thompson-Coon3,
  4. Edzard Ernst4

Editorial Group: Cochrane Heart Group

Published Online: 28 MAR 2013

Assessed as up-to-date: 16 AUG 2012

DOI: 10.1002/14651858.CD003335.pub3


How to Cite

Wider B, Pittler MH, Thompson-Coon J, Ernst E. Artichoke leaf extract for treating hypercholesterolaemia. Cochrane Database of Systematic Reviews 2013, Issue 3. Art. No.: CD003335. DOI: 10.1002/14651858.CD003335.pub3.

Author Information

  1. 1

    University of Exeter Medical School, Institute of Health Services Research, Exeter, UK

  2. 2

    Hospital for Cancer Research, Plau am See, Germany

  3. 3

    University of Exeter, Peninsula CLAHRC, University of Exeter Medical School, Exeter, Exeter, UK

  4. 4

    Peninsula Medical School, Complementary Medicine, Exeter, Devon, UK

*Barbara Wider, Institute of Health Services Research, University of Exeter Medical School, Veysey Building, Salmon Pool Lane, Exeter, EX2 4SG, UK. b.wider@exeter.ac.uk.

Publication History

  1. Publication Status: New search for studies and content updated (no change to conclusions)
  2. Published Online: 28 MAR 2013

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Characteristics of included studies [ordered by study ID]
Bundy 2008

MethodsRandomised, double-blind
2 parallel arms


Participants75 patients with total plasma cholesterol of 0.6 - 0.8 mmol/L
majority of patients (n = 52) over 50 years of age
48 female (24 in each group), 27 male (ALE 14, placebo 13)
Treatment arm: n = 38
Placebo arm n = 37


InterventionsTreatment arm: 320 mg aqueous ALE four times daily. 1280 mg per day.
Control arm: placebo capsules four times daily.
Duration of treatment: 12 weeks


OutcomesTotal cholesterol reduction
HDL cholesterol
LDL cholesterol
Triglycerides


NotesFood diaries reveal that included sample was health-aware, with higher than UK average intake of fruit, dairy, nuts, seeds, whole grain and oily fish.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low risk"Patients were randomised using MINIM software (London Hospital Medical College, UK) with minimization for plasma total cholesterol, age and sex"

Allocation concealment (selection bias)Low risk"Treatment groups were coded by a third party and the code was not broken until after data analysis"

Blinding (performance bias and detection bias)
All outcomes
Low risk"Double-blind", "matched placebo"; author communication: "placebo matched for colour and size". "The 'guess the treatment question' revealed that the placebo capsules were not distinguishable from the ALE capsules by volunteers".

Incomplete outcome data (attrition bias)
All outcomes
Low riskAll 4 withdrawals accounted for: 2 participants in placebo group did not start treatment i.e. no baseline/end data available.

2 further withdrawals (1 in each group) due to adverse events unrelated to study medication.

Selective reporting (reporting bias)Low riskResults reported for all main outcome measures.

Englisch 2000

MethodsRandomised, double-blind
2 parallel arms


Participants143 Caucasian patients aged between 18 and 70 years. Total cholesterol level of greater than 7.3 mmol/L (equivalent to 280 mg/dL).

Treatment arm: n = 71, mean age 54.2 years
Placebo arm: n = 72, mean age 49.7 years


InterventionsTreatment arm: 900 mg artichoke dry extract twice daily. 1800 mg per day.
Control arm: placebo.
Duration of treatment: 6 weeks


OutcomesTotal cholesterol reduction
LDL
HDL
Triglyceride
LDL/HDL ratio


NotesDietary fat intake recorded as high in 11 patients in the treatment arm compared with 30 in the placebo arm.
Significant percentage reduction in total cholesterol levels compared with placebo.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear risk"Patients were randomly allocated to one of the two treatment groups". No further details provided.

Allocation concealment (selection bias)Unclear riskNo details provided.

Blinding (performance bias and detection bias)
All outcomes
Unclear riskDescribed as double-blind but no details provided.

Incomplete outcome data (attrition bias)
All outcomes
Low riskAll patients accounted for, ITT analysis. 12 drop-outs due to protocol violations.

Selective reporting (reporting bias)Low riskData for all main outcomes reported.

Petrowicz 1997

MethodsRandomised, double-blind
2 parallel arms


Participants44 entered / drop outs not reported.
Healthy volunteers, aged 20 - 49 years.

Treatment arm: n = 22
Placebo arm: n = 22


InterventionsTreatment arm: 640 mg artichoke leaf extract three times daily. 1920 mg per day.
Control arm: placebo.
Duration of treatment: 12 weeks.


OutcomesTotal cholesterol reduction


NotesAvailable as abstract only.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low risk"Randomised", additional communication from author (study protocol): participants were randomised using a computer randomisation list.

Allocation concealment (selection bias)Unclear riskNo details provided.

Blinding (performance bias and detection bias)
All outcomes
Low risk"Double-blind", additional communication from author (study protocol): identical placebo, confirms double-blinding of study.

Incomplete outcome data (attrition bias)
All outcomes
Low riskAccording to communication from author, all participants completed the study.

Selective reporting (reporting bias)High riskOnly data from subgroup analyses and selected outcome measures reported.

 
Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion

Anon 2007Review, contains no additional studies

Anon 2008Review, contains no additional studies

Dog 2003Educational review, no additional studies

Dorn 1995Was not a randomised controlled trial although it was described as a randomised controlled trial

Goetz 2007Plant monograph, contains no trial data

Hausler 2003Overview, no trial data

Joy 2007Review, contains no additional studies

Kirchoff 1994Did not measure blood cholesterol

Kraft 2002Review of Schmiedel 2002

Kupke 1991Did not test an ALE mono-preparation

Lupattelli 2004Uncontrolled trial

Meletis 2003Review, contains no additional studies

Montini 1975Did not test whole artichoke leaf extract

Nazni 2006Not randomised

Pittler 2001Review of Englisch 2000

Rondanelli 2011Did not test an ALE mono-preparation

Schmiedel 2002ALE as part of a treatment package including of different dietary interventions, relaxation therapies, physical therapy.

Springer 2003Review, contains no additional studies

Thompson 2003Review, contains no additional studies

Wolf 1996General conference report, no RCT reported

 
Comparison 1. Artichoke leaf extract vs placebo

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Total cholesterol reduction (mmol/L)2211Mean Difference (IV, Fixed, 95% CI)0.60 [0.40, 0.79]

 2 LDL-cholesterol reduction (mmol/L)2211Mean Difference (IV, Fixed, 95% CI)0.56 [0.34, 0.78]

 3 HDL-cholesterol reduction (mmol/L)2211Mean Difference (IV, Fixed, 95% CI)0.03 [-0.11, 0.17]

 4 Triglycerides reduction (mmol/L)2211Mean Difference (IV, Fixed, 95% CI)-0.01 [-0.25, 0.22]

 
Table 1. Results

StudyResults

Bundy 2008Mean changes in total cholesterol concentration - 4.2% for the active group and + 1.9% for the placebo group, total difference (6.1%). Statistically significant (P = 0.025).
No further statistically significant differences in HDL, LDL, TAG between groups.
Only few and minor adverse events which occurred more frequently in the placebo group (11 vs 16). Positive side effects occurred more frequently in ALE group (n = 7) than placebo group (n = 1).

Englisch 2000Mean reduction of total cholesterol was 18.5% (1.43 mmol/L) for the treatment group and 8.6% for the placebo group (0.66 mmol/L), difference of means 9.9%. Statistically significant.

LDL-cholesterol decreased by 22.9% in the ALE group and 6.3% in the placebo group. Difference 16.6%. Statistically significant.

LDL/HDL ratio decreased by 20.2% in ALE group and 7.2% in placebo group. Difference between group 13%.

No statistically significant differences between groups for HDL cholesterol and triglycerides.

26 mild changes in laboratory values including liver enzymes, authors state that the "relationship to the investigational product is rated 'unlikely' in all cases", 2 major AEs unrelated to drug (coronary bypass surgery, pacemaker implantation).

Petrowicz 1997No effect on total cholesterol reduction in total patient population. Sub-group analysis in patients with initial total cholesterol levels of above 210 mg/dL showed that ALE significantly reduced total cholesterol compared with placebo. But this was on few patients therefore data are of limited power, n = 7 control/placebo arm and n = 10 in the treatment arm.