June 18, 2003
Diagnosis and Symptoms
Question from California, USA:
At the time of diagnosis, my C-peptide was 16.4, my A1c was 13.9%, and my fasting glucose was 389 mg/dl [21.6 mmol/L], so my doctor classified me as having type 2 diabetes. However, my recent C-peptide was 4.2, so he reclassified me with LADA, and since my basal/bolus insulin regimen combo wasn't working for control after two and a half years, I've opted to pump.. I've searched the Internet and asked my doctor if there have been any research studies done on the natural progression and transition of someone with LADA. What is your take on this situation? How long does it take for an adult to fully lose beta cell function? I've heard from six months to six years.
The thought is that Late-onset Autoimmune Diabetes of Adulthood (LADA) is associated with a slower progression to absolute lack of insulin. You are correct that the time to no insulin secretion may be months to years. However, it is interesting to note that in individuals with classic type 1 diabetes, it takes years to lose insulin secretion. It is just that we find it so late in the process.
The other thing to keep in mind is that C-peptide needs to be interpreted in light of the current blood sugar. If the result is low and the sugar is low, that is less helpful. If the sugar is high and the C-peptide is low, that means the C-peptide response is inadequate. Absence of C-peptide (lab result of less than 1.0) is usually associated with classic type 1 diabetes and no insulin secretion.