Journal of Endocrinological Investigation

, Volume 39, Issue 2, pp 215–225 | Cite as

Efficacy and safety of oral insulin compared to subcutaneous insulin: a systematic review and meta-analysis

  • V. Akbari
  • F. Hendijani
  • A. Feizi
  • J. Varshosaz
  • Z. Fakhari
  • S. Morshedi
  • S. A. Mostafavi
Original Article



A systematic review and meta-analysis of interventional studies was conducted to compare the efficacy and safety of oral insulin versus subcutaneous (SC) insulin in diabetic patients.


Medline, Scopus, ISI Web of Knowledge and Cochrane Central Register of Controlled Trials were searched. Two independent reviewers evaluated studies for eligibility and quality and extracted the data. The primary outcomes were fasting blood glucose (FBG), 1h and 2h postprandial blood glucose, HbA1c, AUC of insulin, C max and T max of insulin, and T max of glucose infusion rate. Secondary outcomes were adverse events.


Eleven studies (n = 373) met the inclusion criteria. Meta-analyses showed that there is no significant difference between oral and SC insulin in controlling HbA1c, FBG, 1 and 2 h postprandial blood glucose and producing C max of insulin (P > 0.05); however oral insulin had faster action as indicated by the shorter T max, compared to SC insulin (P < 0.05). The most included studies were varied in their methodological quality.


This systematic review and meta-analysis showed that oral insulin is comparable to SC insulin with regard to glycemic efficacy and safety. However, is necessary to conduct additional studies in which oral insulin administered to large number of patients for long enough periods of time.


Oral insulin Subcutaneous insulin Efficacy Safety 



This work was financially supported by the Isfahan University of Medical Sciences (Grant Number 193050).

Conflict of interest

The authors declare that there is no conflict of interest.

Ethical approval

For this type of study formal consent is not required.

Informed consent

For this type of study, informed consent is not required.

Supplementary material

40618_2015_326_MOESM1_ESM.docx (244 kb)
Supplementary material 1 (DOCX 243 kb)


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Copyright information

© Italian Society of Endocrinology (SIE) 2015

Authors and Affiliations

  • V. Akbari
    • 1
  • F. Hendijani
    • 1
  • A. Feizi
    • 2
  • J. Varshosaz
    • 3
  • Z. Fakhari
    • 4
  • S. Morshedi
    • 4
  • S. A. Mostafavi
    • 3
  1. 1.Department of Pharmaceutical Biotechnology, Faculty of Pharmacy Isfahan University of Medical SciencesIsfahanIran
  2. 2.Department of Biostatistics and Epidemiology, Faculty of Public Health Isfahan University of Medical SciencesIsfahanIran
  3. 3.Department of Pharmaceutics, Faculty of PharmacyIsfahan University of Medical SciencesIsfahanIran
  4. 4.Student Research Center, Faculty of PharmacyIsfahan University of Medical SciencesIsfahanIran

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