| Level I | Good quality evidence |
Systematic review of RCTs with consistent findings High quality individual RCT |
| Level II |
Limited quality patient orientated evidence |
Systematic review of lower quality studies or studies with inconsistent findings Low quality clinical trial Cohort studies Case-control studies |
| Level III | Other |
Consensus guidelines, extrapolations from bench research, usual practice, opinion, disease-oriented evidence (intermediate or physiologic outcomes only), or case series |
[5] Metformin: National Department of Health, Essential Drugs Programme: Primary Health Care STGs and EML, 2018. http://www.health.gov.za/
Metformin: Amod A, Ascott-Evans BH, Berg GI, Blom DJ, Brown SL, Carrihill MM, Dave JA, Distiller LA, Ganie YN, Grobler N, Heilbrunn AG, Huddle KRL, Janse van Rensburg G, Jivan D, Joshi P, Khutsoane DT, Levitt NS, May WM, Mollentze WF, Motala AA, Paruk IM, Pirie FJ, Raal FJ, Rauff S, Raubenheimer PJ, Randeree HAR, Rheeder P, Tudhope L, Van Zyl DJ, Young M; Guideline Committee. The 2012 SEMDSA Guideline for the Management of Type 2 Diabetes (Revised) JEMDSA 2012;17(2)(Supplement 1): S1-S95. http://www.semdsa.org.za/images/2012_SEMDSA_Guideline_July_FINAL.pdf
Metformin: Canadian Diabetes Association Clinical Practice Guidelines Expert Committee. Canadian Diabetes Association 2013 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada. Can J Diabetes 2013;37(suppl 1):S1-S212. http://www.ncbi.nlm.nih.gov/pubmed/24070961
Metformin: NICE Clinical Guideline 87: Type 2 diabetes - The management of type 2 diabetes, 2009, 2014. www.nice.org.uk/Guidance/CG87
Metformin: Aronoff, Bennett et al. Drug Prescribing in Renal Failure: Dosing Guidelines for Adults and Children, 5th Edition. American College of Physicians. United States of America, 2007.
Metformin: Lipska KJ, Bailey CJ, Inzucchi SE. Use of metformin in the setting of mild-to-moderate renal insufficiency. Diabetes Care. 2011 Jun;34(6):1431-7. http://www.ncbi.nlm.nih.gov/pubmed/21617112