This is somewhat dated information. Last November, the FDA issued safety information (http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/DrugSafetyInformationforHeathcareProfessionals/ucm188656.htm). From April 2005 to October 2008, there were 78 reported cases of altered kidney function. Some (most?) of the reports involved patients with kidney problems or at risk of kidney problems. Some (most?) involved nausea, vomiting and diarrhea.
Given the low incidence rate, unless you have kidney problems and/or risks and experience nausea, vomiting and diarrhea it is probably not a concern.
ps. I've been on Byetta for two years.