Chinese herbal medicine: developing evidence

1

Chinese herbal medicine: developing evidence

relevant to current practice

Hugh MacPherson

Senior Research FellowDepartment of Health Sciences

[email protected]

DEPARTMENT OF HEALTH SCIENCES

Where do we start?…….. a quote

“A depressed patient who takes St John’s wort and comes out of depression arguably gathers enough strength to commit suicide, so it is dangerous” Ernst (Guardian 4th Oct 2007)


Another quote……

“Today there is not a shred of scientific evidence that traditional herbalists do more good than harm.”Ernst (Post Grad Med Journal Oct 2007)


BIQ QUESTIONS …..

How do we translate the results we see in clinic practice into evidence!!!!

How do we show how safe we are???


Establishing evidence for a new drug

Screening

Mechanism

Efficacy RCT

Effectiveness RCT

Safety


Why use the Randomised Controlled Trial, the (RCT)?

Key reasons are:

Control for natural history of the disease (people tend to recover anyway)

Attribute change to interventionMinimise bias


Two types of RCT:which depend on the research question

Explanatory RCTs answer the question: “is there a herbal component that has an effect per se?”

(for component efficacy, we need a placebo comparison)

Pragmatic RCTs answer the question: “is there an effect of herbal medicine as a package?”

(for system effectiveness, we need a real world comparison)


Explanatory and pragmatic RCTs

real world comparisonplacebo controlledchronic conditionsacute conditionsroutine practiceexperimental contextEffectiveness overallEfficacy of components

high external validityhigh internal validityindividualised Trstandardised Tr

Pragmatic RCTExplanatory RCT


Question: how do we conceptualise herbal medicine?

A simple intervention:Single herbs prescribed by symptomLimited or no theory

A complex intervention:Multiple herbsSynergistic interactionsInformed by theory


TOTAL ACTUALBENEFIT

BENEFIT DUE TO SPECIFIC

HERBS

BENEFIT DUE TO INTERACTIONS AND PROCESSES

BENEFIT DUE TO

PLACEBO

HERBAL MEDICINE AS COMPLEXINTERVENTION


New drug(release process)

Screening

Mechanism

Component efficacy

System effectiveness

Safety

Utilisation

Safety

System effectiveness

Component efficacy

Mechanism

Chinese herbs(in widespread use)


Safety of routine practice?

The Australian data – retrospective practitioner survey conducted in 1996*1100 practitioners participatedFindings: one adverse event per 9 months, commonly:

Gastrointestinal symptomsSkin reactionsSevere fatigue

* Bensoussan & Myers 1996


Safety of routine practice in UK?

Research question:

“What adverse events are associated with

routine practice of Chinese herbal medicine

in the UK when prescribed by RCHM

members?”

MacPherson H, Liu B. "The safety of Chinese herbal medicine: a pilot for a national survey." Journal of Complementary & Alternative Medicine. 2005; 11(4): 617-626.


Research methods

Longitudinal study over 1 month

549 RCHM practitioners invited

71 participated (13%) – asked to hand out survey forms to 10 patients

48% practitioners are female average 10 years in practiceaverage treated 10 herbs patients a week


Who are our patients?

78% femaleMean age 45 yrs44% had symptoms > 5 years84% had seen GP about condition


Four week follow-up …..

144 patients responded (20% of max)70% consulted more than once in 4 weeks74% took herbs all 4 weeksNot recorded:

DiagnosisPrescriptionsIndividual herbsMedication


What type of herbal preparation?

38% herb powder27% raw herb decoction23% tablet4% tincture


Commonly reported reasons for consulting:

15% gynaecology12% skin conditions12% digestive related12% general health10% psychological


Adverse events at four weeks

32 20 patients

Total eventsReported by

12Other3Headache 4Abdominal pain4Nausea4Fatigue6Diarrhoea

Number of events


Attribution of the events to the herbs

Of the 20 who experienced events: 11 patients said event(s) definitely or probably associated with herbs

For all 8 patients who reported discontinuing herbs, the symptoms recededFor all 4 who reported restarting taking the herbs, the symptoms returned


Tolerance of events

Regarding adverse event: 2 said “extremely bothersome” 4 said “very bothersome” 7 said “bothersome”

16 out of 20 patients would be willing to have Chinese herbal medicine again


What factors might be possible risk factors?

Practitioner factorsGender

Patient risk factorsGenderGP contact before surveyGP contact during 4 weeksNumber of herb consultations during 4 weeksFirst consultation with herbal practitioner (p=0.02)


Limitations 1: poor response rate

13% of RCHM members participated(71 out of 549)

20% of possible maximum number of patients participated (144 out of 710)(2 per practitioner)


Explanations (from 90 practitioners) for non participation

29% “too busy”26% “not in practice”17% “away”14% “too few patients”


Limitations 2: Difficulties with interpretation

Precise herbs & preparations used not knownHerb prescriptions not known

Herb-herb interactions?

Conventional medication not knownHerb-drug interactions?


Limitations 3: reporting bias from those who did respond

Possible under-reporting:Patients not attributing event to herbs?Patients wanting to “protect” practitioner?

Possible over-reporting:Patients incorrectly attributing event to herbs?Check lists associated with higher response rates?


Limitations 4: sample size too small

Large numbers are needed to know the incidence of serious adverse events

What is a serious adverse event?HospitalisationLife-threatening


Limitations 5: practitioner errors of omission/commission not addressed

OmissionMissing serious pathologyMissing serious side effects of herbs

Commission Inappropriate advice about medication


Strengths of study - 1

First study to identify the patient perspective on safety

Patient reports are more reliable than practitioner reports


Comparing patient reports with practitioner reports for herbal medicine

1 event per 2 months(32 events/71 practitioners/month)

1 event per 9 months

Adverse event rate per practitioner

144 patients in UK

1100 practitioners in Australia

Who reported events

Patient studyPractitioner study


Strengths of study - 2

Methodology has been tested with acupuncture: two studies with practitioners and patients reporting:

British Medical Journal 2001; 323: 486-487

Quality & Safety in Health Care. 2004; 13: 349-355


Acupuncture safety study - 1

Practitioner study - one month data collecting574 BAcC acupuncturists reported Covered 34,000 consultations No serious adverse events43 minor adverse events

BMJ editorial: “Acupuncture is safe in competent hands”. [Charles Vincent BMJ 2001:323:467-8]


Acupuncture safety studies - 2

Patient study – 3 months data collecting from 638 BAcC acupuncturists

6348 patients reported that over 3 months no serious adverse events 1044 minor events omission/commission: 2 cases of missed diagnosis or delayed

treatment – none serious 6 cases of advice about medication reduction caused reactions – caused return of prior symptoms


Acupuncture vs. Chinese herbal medicine – comparing conditions

•Musculo-skeletal•Depression•Eczema•Chronic pain•IBS

•Gyn•Skin•Digestive•General•Psychological

•Musculo-skeletal•Psychological•General•Neurological

Common conditions

Effectiveness gaps in primary care [Fisher 2004]

Chinese herbs patients

Acupuncture patient(Study 2)


Acupuncture vs. herbal medicine – comparing type of adverse events

•Diarrhoea •Fatigue•Nausea•Abdominal pain•Headache

•Tiredness•Pain on needling•Dizziness•Headache

Common adverse events

Chinese herbs patients

Acupuncture patients(Study 2)


Acupuncture vs. Chinese herbal medicine – comparing event rate

0.5 events per month

0.5 eventsper month

0.1 events per month

Event rate per practitioner

RCHM patients

BAcC patients

BAcC practitioners

Who reported

Chinese herbs patientstudy

Acupuncture patient study(Study 2)

Acupuncture practitioner study (Study 1)


Future strategies 1 – replicating this research as full-scale study?

Funding requiredOpportunity to establish more robust data

Large sample size Better response rate….


Comparing practitioner response rates

13% 31% 33%Response rate of practitioners

Chinese herb patients study

(RCHM)

Acupuncture patient study

(BAcC)

Acupuncture practitioner

study (BAcC)


Future strategies 2 – other options

Case control studyFollow over time “cases” (patients) who receive same herb(s), along with matched patients who do notBUT – not feasible with individualised multiple herbs

Yellow card schemeVolunteer monitoring nationallyReputation for under-reporting


Conclusions:

We now know the commonest adverse events The adverse event rate is higher than for acupunctureMost people are willing to continue in spite of adverse eventsPatients consulting for the first time are most likely to experience an adverse event


Strategies for appropriate evaluation

real-world designs:

pragmatic RCTs for effectiveness cost-effectiveness longer-term outcomes qualitative research

large scale surveys for safety


What to do about research?

Herbalists need to engage in researchHelp design studies and trialsProvide data on herbal medicine that is representative of practiceBuild a relevant evidence base


Acknowledgments for herb study

Patients and practitionersBin LiuAdvisors

Trevor SheldonTrina WardJeremy Miles

FundersRCHMUniversity of York

Chinese herbal medicine: developing evidence

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