Partial Remission in Type 1 Diabetes Associated With Long-Term C-Peptide Levels

Patients with partial remission of type 1 diabetes were found to have a distinct, 3-phase pattern of C-peptide decline, and the effects of partial remission remain after remission ends, according to the results of a study published in Diabetes/Metabolism Research and Reviews.

Investigators sought to determine the different patterns of C-peptide decline among patients with and without partial remission of newly diagnosed type 1 diabetes. A total of 298 patients from a hospital in China were screened from May 2010 to October 2018 and included in the analysis. Participants were followed at 3-month intervals regarding daily insulin dose, glycated hemoglobin (HbA_1c), fasting C-peptide, and 2-hour postprandial C-peptide.

Partial remission was determined by a 2-hour postprandial C-peptide level ≥300 pmol/L or insulin dose-adjusted HbA_1c ≤9% in the absence of C-peptide. Beta-cell function was defined as preserved, residual, or failed corresponding with a 2-hour postprandial C-peptide level of ≥200, 50 to 200, or ≤50 pmol/L, respectively.

The patients were followed for a median of 24.4 months (15.6-38.2 months), and 199 patients (125 adults) had partial remission. Of this group, 136 patients (92 adults) ended their partial remission during follow-up. Patients with and without partial remission had significant differences in age, body mass index, islet autoantibodies, fasting C-peptide, 2-hour postprandial C-peptide, and HbA_1c at baseline.

Among participants with partial remission, 3 phases of C-peptide change were observed, as PCP increased to 161.200 pmol/L/mo (101.510-220.880) in the first 2 months, was -11.299 pmol/L/mo (-13.438 to -9.160) from months 2 to 36, and was -2.596 pmol/L/mo (-5.854 to 0.663) after 36 months. In the no partial remission group, C-peptide change had a biphasic decline without an initial increase, as PCP was -5.917 pmol/L/mo (-7.889 to -3.944) for the first year and had a relatively stable decrease at -0.766 pmol/L/mo (-1.379 to -0.154) afterward.

According to the researchers, the changes in C-peptide among the participants suggested a 3-phase pattern, which was consistent when patients were grouped into those with juvenile-onset disease (<18 years of age) and adult-onset disease (≥18 years of age). The C-peptide change patterns were significantly different in subgroup analysis regarding those with partial remission and those with no partial remission.

The proportion of patients with failure of beta-cell function was 29% in the partial remission group and 89% in the no partial remission group at 3 years. No patients in the no partial remission group had preserved beta-cell function after 18 months, and 23% in the partial remission group had preserved beta-cell function at 3 years.

Among several study limitations, the investigators noted that the time intervals between follow-up assessments and the starting and endpoints of partial remission could not be determined precisely. Also, the study authors used C-peptide as the priority criterion to determine partial remission, with 80% of patients identified by 2-hour postprandial C-peptide levels. Furthermore, the study was conducted at a single center study with a limited number of patients in 1 geographic area.

“This study confirms that there are different patterns of C-peptide change depending on the status of partial remission in type 1 diabetes patients, and the presence of partial remission has potential beneficial influence on long-term beta-cell function,” the investigators commented. “These findings suggest that there are unrecognized different biological processes before, during, and after remission, and have important clinical and scientific implications.”

Reference

Shi M, Xie Y, Tang R, Zhou Z, Li X. Three-phasic pattern of C-peptide decline in type 1 diabetes patients with partial remission. Diabetes Metab Res Rev. Published online April 29, 2021. doi:10.1002/dmrr.3461