Obat Herbal: Antara Reputasi dan Bukti

Laetrile: Reputasi VS Bukti Pada Kanker Lanjut

Laetrile (singkong beracun) termasyhur sebagai obat kanker. US Nationa Cancer Institute (1978) memperkirakan 70 000 pasien telah diobati dengan laetrile; hanya 93 orang yang terdokumentasi, responsenya dapat dinilai, 6 orang dinyatakan ada response.

Moertel dkk (1982) lakukan uji klinik tak terkontrol pada 178 penderita kanker lanjut. Median survival time 4.8 bulan, bebrapa orang cepat mati karena intoksikasi sianida.

Vitamin C Dosis Tinggi: Reputasi VS Bukti Pada Kanker Lanjut Ascorbate-treated terminal cancer patients vs

matched controls: the ascorbate-treated patients were found to have a mean survival time about 300 days greater than that of the control (Cameron&Pauling, 1978)

In a double-blind study 100 patients with advance-naïve colorectal cancer were randomly assigned to either high-dose vit.C (10 gr daily) or placebo. Vit C therapy showed no advantage over placebo therapy with regard to either interval between the beginning of treatment and disease progression or patient survival (Moertel et al, 1982).

Improved and Unimproved BPH Treated with Saw Palmetto 3139 men from 21 randomized trials lasting 4-48

weeks were assessed. 18 trials were double-blinded and treatment allocation concealment was adequate in 11 studies. Compared with placebo, saw palmetto improved urinary symptoms score, symptoms and flow measure (Wilt et al, 2006).

225 men over 49 years who had a moderate to severe symptoms of BPH were randomly assigned to one year of treatment with saw palmetto (2X160 mg daily) or placebo. Saw palmetto did not improve symptoms or objective measures of BPH (Bent et al, 2006).

This studies raise questions about the variability of botanical products and indicate additional studies are needed to reach firm conclusion (Peola et al, 2006)

Bias in Systematic Review of Herbal Medicinal Products

Reporting bias: publication bias, language bias, citation bias, multiplr publication bias.

True heterogeneity: size effect differs according to study size, intensity of intervention, different in underlying risk.

Data irregularities: poor methodological design of small studies, inadequate analysis, fraud.

Chance factor

Concern in Herbal Medicinal Products Trials of herbal medicinal products have been too few,

too small, and too short. The clinician is caught between encouraging results of

RCTs and the relative lack of controlled long-term data.

Systematic reviews have limitations in area of herbal medicine. They are limited by the quality and quantity of the primary studies.

Because herbal medicinal products cannot be patented, the incentives for research investments are lower.

Lack quality control and standardization of herbal medicinal products is of concern of many experts.

Various Expectation Effects Behind the Placebo Response Hawthorne effect : Subjects respond to knowledge of being

evaluated and observed. Jastrow effect : Subjects respond to explicit expectation about outcome. Pygmalion effect : Evaluator expect therapeutic benefit, so they see it. John Henry effect : Control subject attempt to emulate expected outcomes. Halo effect : Subjects respond to treatment novelty. Experimenter effect: Evaluators interpreted outcome differently. Socialization effect : Other reporting apparent effect influence the outcome. Value effect : Costs influence expected outcome.