Human versus animal insulin in people with diabetes mellitus. A systematic review

This review is in accordance with the findings of the systematic review of Airey et al [18] with respect to the absence of a differential effect on hypoglycemia between human and animal insulin. For the first time, however, the review compares the relative efficacies of human and animal insulin, which indicates that human insulin was introduced without proof of being superior to animal insulin. Studies have not assessed patient-centered outcomes [41,42], such as patient satisfaction, health-related quality of life, and diabetes-related morbidity. Randomized trials did not report on qualitative assessments of patients' experiences when using different insulin species. Because history tends to repeat itself, we probably will be faced with other "innovations" (e.g., insulin analogs) evaluated in clinical trials tht focus on surrogate outcomes followed by marketing of insulins "proved" to be effective in short-term, underpowered, and badly executed studies.