One-year progression from prediabetes to type 2 diabetes in a Turkish primary-care cohort: a prospective study

To estimate one-year progression to type 2 diabetes among adults with prediabetes in primary care and explore associated baseline characteristics.

Adults with prediabetes identified using FPG, 2-h OGTT glucose and/or HbA1c criteria at a Turkish family health centre were followed for one year. Incident diabetes was defined by repeat-confirmed diabetes-range FPG or HbA1c; the oral glucose tolerance test was not repeated at follow-up, for resource and participant-burden reasons. Progressors and non-progressors were compared using Mann-Whitney U and Fisher's exact tests, without adjustment for multiple comparisons. ROC analyses were exploratory, and the derived cut-offs were neither internally nor externally validated.

Among 152 participants (67.8% women; mean age 52.9 ± 12.6 years), 9 (5.9%; 95% CI 2.7-10.9%) progressed to diabetes, while 20 had normal-range FPG and HbA1c and 123 retained prediabetes-range values. Progressors had higher BMI, waist and hip circumference, FPG, HbA1c and 2-h glucose; antidepressant use was also more frequent, although this unadjusted association is likely confounded by indication. All nine incident cases occurred in participants with combined IFG and IGT. In exploratory analyses based on only nine events, higher 2-h glucose showed the strongest apparent separation between progressors and non-progressors.

One-year progression was uncommon but concentrated among participants with combined IFG and IGT. Because only nine events occurred, roughly two dozen baseline factors were compared without adjustment for multiple testing, and the OGTT was not repeated at follow-up, every association reported here is hypothesis-generating and the study-derived thresholds are exploratory and unvalidated; neither should be used to guide clinical decisions until confirmed in larger, independent cohorts.