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Cochrane Database of Systematic Reviews Protocol - Intervention

Botanical medicine for low‐back pain

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Abstract

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

To determine the effectiveness of botanical medicine compared to placebo, no intervention, or other interventions in the treatment of non‐specific low‐back pain.

Background

Low‐back pain and related disability are major public health problems across industrialized nations. As a result, the past 15 years have seen an intensive research effort to identify effective treatment and management strategies for low back pain (Mounce 2002). The one‐month prevalence of low‐back pain is reported to be between 35 and 37 per cent, with a lifetime prevalence between 70 and 85 per cent, peaking between 45 and 59 years of age (Papageorgiou 1995; Andersson 1999). In the United States back pain is the most common cause of disability in those under 45 years of age (Borkan 1995) and back sprains and strains represent about one quarter of work‐related injuries resulting in lost work‐days (Dept Labor 1995). Low back pain is the second most frequent cause of work absence in industrialized nations (Praemer 1992) and is a frequent reason for visits to a physician (Coste 1994; Andersson 1999). It has been estimated that in the United States back pain has associated direct costs of 20 billion dollars and indirect costs of between 75 and 100 billion dollars (Borkan 1995). In the United Kingdom costs associated with low back pain are estimated to be over 500 million pounds (Little 1996). This amounts to a substantial productivity and economic burden for health‐care systems in many industrialized countries (Mounce 2002).

The traditional treatment of low‐back pain includes medication, tissue stimulation (e.g. TENS, ultrasound), rest and orthotics (e.g. braces; Cherkin 1993). Although systematic reviews suggest that few of these have enough evidence to suggest benefit, it does appear that acute low‐back pain can be effectively managed by encouraging activity, reassurance and short‐term symptom control (analgesics or NSAIDs; van Tulder 2002a). Effective management of chronic low‐back pain consists of exercise therapy, behavioural treatment and multidisciplinary treatment programs (van Tulder 2002b). Also, altering beliefs about back pain that are correlated with impairment or disability is one of the major challenges in low‐back pain management (Borkan 1995).

Research in complementary and alternative medicine (CAM) has blossomed in the past 10 years. Rigorous literature is growing steadily and is subsequently clarifying the validity of these techniques. Specifically, the number of randomised trials of complementary treatments has been doubling approximately every five years (Vickers 2000) and currently, the Specialized Trial registry of the Cochrane Collaboration Complementary Medicine field contains over 6500 randomized and controlled clinical trials. In addition, CAM‐teaching institutions are now beginning to teach principles of evidence‐based medicine and clinical epidemiology (Mills 2002; Sierpina 2002). These initiatives are well placed, given the large number of visits to CAM practitioners (Millar 2001). A recent population survey in Canada found that 2.2 million women and 1.6 million men visited a CAM practitioner during 1998/1999 (Millar 2001). Of these, it was found that more than 26 per cent of patients who reported chronic pain visited an alternative practitioner during the previous year, compared with only 15 per cent who did not report chronic pain. Those who reported back pain had a higher percentage of visits to alternative practitioners than any other pain condition. More specifically, 37 per cent of the individuals who reported back pain visited an alternative practitioner compared with only 17 per cent of the entire population (Millar 2001). Similar percentages have been found in surveys conducted in the United States (Eisenberg 1998; Astin 2000; Druss 1999).

Several herbal medicines have been reported as treatments for varying types of pain. These include: Camphora molmol, Capsicum frutescens, Salix alba, Maleluca alternifolia, Angelica sinensis, Aloe vera, Thymus officinalis, Menthe peperita, Arnica montana, Curcuma longa, Tancaetum parthenium, Harpagophytum procumbens, and Zingiber officinicalis (Blumenthal 1998). Many of these herbs have been the subject of extensive biochemical research leading to delineation of their pharmacology and physiological effects (Mills 2000). In addition, some of these botanical species have been clinically tested for the relief of symptoms of low‐back pain (Mills 2000; Stam 2001; Laudahn 2001; Krivoy 2000).

Given the large public health and economic burden low‐back pain causes and the large number of such sufferers who regularly visit CAM practitioners, a systematic review of these practices is warranted.

Objectives

To determine the effectiveness of botanical medicine compared to placebo, no intervention, or other interventions in the treatment of non‐specific low‐back pain.

Methods

Criteria for considering studies for this review

Types of studies

Only randomized controlled trials (RCTs) will be included.

Types of participants

Adults, (older than 18 years of age) suffering from acute (less than or equal to 6 weeks), sub‐acute(greater than 6 weeks and less than 12 weeks) or chronic (greater than 12 weeks) non‐specific low‐back pain.

Low‐back pain is defined as pain localized to the area between the costal margin or the 12th rib to the inferior gluteal fold. Non‐specific low‐back pain indicates that no specific cause is detectable, such as infection, neoplasm, metastasis, osteoporosis, rheumatoid arthritis, fracture, inflammatory process or radicular syndrome (Waddell 1996).

Types of interventions

For the purpose of the present review a botanical medicine is defined as a whole or part of a plant that is used for medicinal purposes with an administration route being oral ( taken by ingestion) or topical. This definition does not include smoked plant substances (e.g. Cannabis sativa), individual chemicals derived from plants or synthetic chemicals based upon constituents of plants. Although, Cannabis sativa, or additional plants which can be smoked, if orally ingested will be considered botanical medicines for this review. Various forms of oral botanical medicine include: standardized extracts (encapsulated or tablet form) , tinctures (alcohol, glycerine, etc), dried herb (encapsulated or tablet form), raw whole herb, infusion (e.g. tea) and decoction (e.g. boiled down tea). Various forms of topical botanical applications include: ointments, essential oils, creams (petroleum or glycerine based), powders, plasters and poultices. Opioids will be excluded from this review given that they bridge the definitions of botanical medicine and analgesic.

Types of outcome measures

1.Pain intensity [e.g., visual analogue scale (VAS), numerical rating scale (NRS)] and proportion of pain free patients.
2.Back pain specific functional status expressed by validated instruments [E.g. Roland Disability Questionnaire (RDQ), McGill Pain Questionnaire, SF‐36 (The MOS 36‐item short‐form survey) and Owestry Disability index (ODI)]
3.Overall improvement (% subjective improvement, NRS)
4.Return to Work or Work Status (% 0f population, number of days of absenteeism).

Search methods for identification of studies

The Following Databases will be searched:
1. MEDLINE (1966 to April 2003)
2. EMBASE (1980 to April 2003)
3. Cochrane Central Register of Controlled Trials (Issue 1, 2003)

The search strategy to be used for spinal disorders is that recommended by the Cochrane Back Review Group (van Tulder 1997; Robinson 2002).

Search strategy:
01 randomized controlled trial.pt 02 controlled clinical trial.pt 03 Randomized Controlled Trials/ 04 Random Allocation/ 05 Double‐Blind Method/ 06 Single‐Blind Method/ 07 or/1‐6 08 Animal/ not Human/ 09 7 not 8 10 clinical trial.pt 11 explode Clinical Trials/ 12 (clinic$ adj25 trial$).tw 13 ((singl$ or doubl$ or trebl$ or tripl$) adj (mask$ or blind$)).tw 14 Placebos/ 15 placebo$.tw 16 random$.tw 17 Research Design/ 18 (latin adj square).tw 19 or/10‐18 20 19 not 8 21 20 not 9 22 Comparative Study/ 23 explode Evaluation Studies/ 24 Follow‐Up Studies/ 25 Prospective Studies/ 26 (control$ or prospective$ or volunteer$).tw 27 Cross‐Over Studies/ 28 or/22‐28 29 28 not 8 30 29 not (9 or 21) 31 9 or 21 or 30 32 low back pain/ 33 low back pain.tw 34 backache.tw 35 lumbago.tw 36 or/32‐35

Additional terms for herbal medicine include: herb, herbal, plant, phytomedicine, botanical, herbs, weed, algae, fungi, fungus, "traditional medicine", phytotherapy, pharmacognosy, "oriental traditional", "Chinese traditional", Camphora molmol, Capsicum frutescens, Salix alba, Maleluca alternifolia, Angelica sinensis, Aloe vera, Thymus officinalis, Menthe peperita, Arnica montana, Curcuma longa, Tancaetum parthenium, Harpagophytum procumbens, and Zingiber officinicalis.

A similar strategy will be used for Embase (van Tulder 1997) and a slightly modified strategy for the Cochrane Central Register of Controlled Trials. Reference lists in review articles, guidelines and in the retrieved trials will be reviewed for additional trials. Additionally, individuals with expertise in botanical medicine and low back pain will be contacted by JG to isolate additional trials. Non‐English articles will be translated and discussed by JG and MvT following the same procedures described below.

Data collection and analysis

One author (JG) will conduct the electronic searches using the above search strategy in all databases. Two authors (JG & MvT) will select studies based on title, abstract, and keywords. Studies that meet the inclusion criteria (see types of studies, participants, interventions and outcomes above) will be included in the review. If it is unclear from title and abstract if a study meets the inclusion criteria or not, a full copy will be retrieved for final selection. A consensus method will be used to resolve disagreements about inclusion of studies. A third author (BB) will be consulted if disagreement persists

Methodological quality assessment
Methodological quality will be independently assessed by two authors (JG & MvT). Given one of the authors' (JG) familiarity with the literature studies will not be blinded for authors, institution and journal. The eleven items reflecting internal validity, together with operational definitions, recommended in the update of the method guidelines for systematic reviews by the Cochrane Back Review Group will be used to assess methodological quality. Each criterion can be scored as "yes"(Y), "no"(N) or "don't know"(DK). The score of 'yes' will reflect the fulfillment of that criterion. The scoring of 'no' will reflect the lack of fulfillment of that criterion. The scoring of 'don't know' will reflect that it was not possible to determine if this criterion was fulfilled or not. A trial will be considered high quality if more than 50 per cent of internal validity items scored positively, i.e. scores of 6,7,8,9,10 out of 11. Authors will be contacted to provide additional information to clarify 'don't know' scorings and to clarify why they don't agree with our positive or negative scores, if relevant.

Internal validity criteria
1.Was the method of randomization adequate?Yes / No / Don't know
2.Was the treatment allocation concealed?Yes / No / Don't know
3.Were the groups similar at baseline regarding the most important prognostic indicators?Yes / No / Don't know
4.Was the patient blinded to the intervention?Yes / No / Don't know
5.Was the care provider blinded to the intervention?Yes / No / Don't know
6.Was the outcome assessor blinded to the intervention?Yes / No / Don't know
7.Were co‐interventions avoided or similar?Yes / No / Don't know
8.Was the compliance acceptable in all groups?Yes / No / Don't know
9.Was the drop‐out rate described and acceptable?Yes / No / Don't know
10.Was the timing of the outcome assessment in all groups similar?Yes / No / Don't know
11.Did the analysis include an intention‐to‐treat analysis?Yes / No / Don't know

Data extraction
Two authors (JG & MvT) will extract the data from each trial using a standardized form. The following data will be extracted from each study: recruitment, characteristics of the study population (age, gender), setting (e.g. year, country of origin), duration of low‐back pain (acute, subacute, or chronic), previous treatment for low‐back pain, number of patients initially recruited, number of patients randomized, number of drop‐outs or withdrawals, duration of intervention, type of botanical medicine used (plant name and form of delivery and dosage), standardization information (e.g. percentage of active constituent per delivery unit), characteristics of the control intervention (type and duration), types of outcome measures, summary statistics, timing of outcome assessments, compliance, adverse effects due to intervention, and author's conclusions as to the effectiveness of the intervention.

Clinical relevance

The clinical relevance of the studies will be independently assessed by two authors. The following five questions will be used:
1.Are the patients described in detail so that you can decide whether they are comparable to those that you see in your practice?
2.Are the interventions and treatment settings described well enough so that you can provide the same for your patients?
3.Were all clinically relevant outcomes measured and reported?
4.Is the size of the effect clinically important?
5.Are the likely treatment benefits worth the potential harms?

Data analysis
The statistical analysis will follow the recommendations of the Cochrane Handbook and the Cochrane Back Review Group (van Tulder 1997). Separate analyses will be conducted for each botanical medicine versus placebo, no intervention, or other treatments, and separately for short (6 to 12 weeks), intermediate (greater than 12 weeks and less than 12 months) and long‐term (greater than or equal to 12 months) follow‐up. Effects measures to be calculated for dichotomous outcomes in each study will include: relative risk (RR). For continuous outcomes, standardized mean difference (SMD) will be calculated across trials. All the above treatment effects will be presented with 95 per cent confidence intervals.

A quantitative or meta‐analysis will be conducted if studies provided sufficient data. The results will be tabulated and formally tested for statistical homogeneity. If data are statistically heterogeneous, reasons for heterogeneity will be explored. Data will be pooled using the random effects model and results plotted as relative risks (RR) with corresponding 95% confidence intervals (95% CI). If studies are statistically or clinically heterogeneous or do not provide sufficient data, a qualitative analysis will be performed using a rating system consisting of 4 levels of evidence:
Strong evidence ‐ consistent findings among multiple high quality RCTs
Moderate evidence ‐ consistent findings among multiple low quality RCTs and/or one high quality RCT
Limited evidence ‐ one low quality RCT
Conflicting evidence ‐ inconsistent findings among multiple RCTs
No evidence from trials ‐ no RCTs

Sensitivity analyses will be carried‐out exploring the results when definitions of high quality trials are 40 per cent and 60 per cent fulfillment of internal validity criteria. Also, the validity criteria that are scored as "DK" will be assumed to be positive for an additional sensitivity analysis.

Planned subgroup analyses will include: acute, sub‐acute and chronic low‐back pain for each botanical medicine. An example of the subgroup analysis that will be undertaken separately for each botanical medicine is as follows.

Subgroup analyses:

Subgroup 1: Acute low back pain without neurological symptoms.
Comparison 1.1: botanical medicine #1 vs. placebo/sham/no treatment
Outcome 1.1.1: pain intensity
Follow‐up: short‐term
Intermediate
long‐term
Outcome 1.1.2: functional status
Follow‐up: short‐term
Intermediate
long‐term
Outcome 1.1.3
Comparison 1.2: botanical medicine #1 vs. active treatments
Outcome 1.1.1: pain intensity
Follow‐up: short‐term
Intermediate
long‐term
Outcome 1.1.2: functional status
Follow‐up: short‐term
Intermediate
long‐term
Outcome 1.1.3

Subgroup 2: Acute low back pain with neurological symptoms.
Comparison 2.1: botanical medicine #1 vs. placebo/sham/no treatment
Outcome 2.1.1: pain intensity
Follow‐up: short‐term
Intermediate
long‐term
Outcome 2.1.2: functional status
Follow‐up: short‐term
Intermediate
long‐term
Outcome 2.1.3
Comparison 2.2: botanical medicine #1 vs. active treatments
Outcome 2.1.1: pain intensity
Follow‐up: short‐term
Intermediate
long‐term
Outcome 2.1.2: functional status
Follow‐up: short‐term
Intermediate
long‐term
Outcome 1.1.3

Subgroup 3: Subacute low back pain without neurological symptoms.