Evaluation of clinical trials for natural products used in diabetes: An evidence-based systemic literature review

BACKGROUND RELEVANCE: A plethora of literature is available regarding the clinical trials for natural products however; no information is available for critical assessments of the quality of these clinical trials. AIM OF STUDY: This is a first time report to critically evaluate the efficacy, safety and large scale applications of up-to-date clinical trials for diabetes, based on the three scales of Jadad, Delphi, and Cochrane. METHODOLOGY: An in-depth and extensive literature review was performed using various databases, journals, and books. The keywords searched included, “clinical trials,” “clinical trial in diabetes,” “diabetes,” “natural products in diabetes,” “ethnopharmacological relevance of natural products in diabetes,” etc. RESULTS: Based on eligibility criteria, 16 plants with 74 clinical trials were found and evaluated. Major drawbacks observed were; “non-randomization and blindness of the studies,” “non-blindness of patients/healthcare/outcome assessors,” “lack of patient compliance and co-intervention reports,” “missing information regarding drop-out/withdrawal procedures,” and “inappropriate baseline characteristics.” Principal component analysis and Pearson correlation revealed four components with %variability; PC1: 23.12, PC2: 15.83, PC3: 13.11, and PC4: 11.38 (P ≤ .000). According to descriptive statistics, “non-blinding of outcome assessors” was the major drawback (82%) whereas, “not mentioning the timing of outcome assessment” was observed lowest (6.8%). An in-house quality grading (scale 0–24) classified these clinical trials as; poor (67.6%), acceptable (19.9%), and good quality trials (13.5%). CONCLUSION: Proper measures in terms of more strict regulations with pharmacovigilance of plants are utmost needed in order to achieve quality compliance of clinical trials.