Although the idea of preventing the onset of diabetes in people at risk for type 1 was recently introduced in the Diabetes Prevention Trial of Type 1 (DPT-1), a group of Italian researchers report that the treatment does not have similar effects in people who have already contracted the disease. In a study published in the August issue of Diabetologia, the researchers report that giving oral insulin to newly diagnosed individuals with diabetes may be doing too little too late.
Taking its cue from the DPT-1 findings and studies that showed a halting of type 1 in animals, the Italian study sought to gauge the effects of oral insulin on the earliest stages of type 1. The test’s 82 subjects were divided into two groups-46 of them taking a daily five mg dose of oral insulin and 36 taking a placebo-then examined them over the course of a year. The subjects’ C-peptide and HbA1c levels were measured every three months, as were insulin requirements. All of the subjects were placed under observation within four weeks of their diagnosis.
In both groups, insulin requirement was reduced after three months of treatment, but rose in similar increments over the course of the year. The group taking oral insulin had a slightly higher average HbA1c at the first observation than the placebo group. Although this difference tapered somewhat during later readings, both groups’ HbA1cs had risen by roughly the same amount at the study’s end. The subjects’ C-peptide measurements, which indicate the body’s production of natural insulin, both began at a slightly below-average 0.3 nmol/l, but the final reading showed that total levels were lower for both groups, substantially more so in those taking oral insulin.
Despite two subjects, one in each group, who went into brief periods of clinical remission, the study’s authors conclude that daily doses of oral insulin have little to no effect on the function of residual beta cells. They expressed particular concern over the disparity in insulin production, as indicated by the C-peptide levels. The researchers say the oral insulin group’s low C-peptide levels may even indicate that the drug hastens the decline in beta-cell function, because insulin is the major target of the auto-immune attack against beta cells.
The study concludes that a daily dose of oral insulin may have its uses in slowing the actual development of type 1, but that it is most likely useless once the disease has been diagnosed.