Metformin Reduces Serum CA199 Levels in Type 2 Diabetes Chinese Patients with Time-Effect and Gender Difference.

Background: This study was designed to clarify the influence of metformin on serum carbohydrate antigen 199 (CA199) levels and its associated factors in Chinese type 2 diabetes mellitus (T2DM) patients. Subjects and Methods: In total, 1,253 T2DM patients were enrolled, including a non-metformin group ( n=616), a short-term metformin group (at least 1 week to 2 years; n=325), and a long-term metformin group (≥2 years; n=312). Their clinical and biochemical characteristics were collected and compared. After 1 year, the biochemical parameters were re-examined in 296 patients. Sex hormones were determined, and associations between CA199 and other variables were assessed. Results: At baseline, the incidence of abnormal CA199 levels was 14.7%, 8.9%, and 4.7% in the non-metformin, short-term metformin, and long-term metformin groups, respectively. CA199 levels in females were significantly higher than in males ( P<0.01) and decreased significantly with the time of taking metformin (25.60±13.68 U/mL in non-metformin controls vs. 17.62±10.87 U/mL in the short-term group vs. 10.54±8.14 U/mL in the long-term group; P=0.000). The correlation and multiple stepwise regression analysis revealed that glycosylated hemoglobin, metformin, gender, total cholesterol, and follicle-stimulating hormone were independent impact factors on CA199 concentrations (all P<0.05). Binary logistic regression revealed that the risk of abnormal CA199 concentrations of the total population with short-term metformin or long-term metformin treatment decreased 11% (odds ratio=0.89; P=0.001) and 30% (odds ratio=0.70; P=0.000), respectively, at baseline. After a 1-year follow-up, the incidence of high CA199 level decreased in both the short-term and the long-term metformin group compared with that of controls ( P<0.05). The extent of CA199 decrease in the long-term metformin group was the greatest (−17% vs. −4.9% in the short-term group vs. 3% in controls, P=0.000), and the group's risk of high blood CA199 level was reduced 67% (odds ratio=0.33; P=0.023). The reduction in women was more apparent than that in men (−18% vs. −5%, P=0.000). Conclusions: Metformin therapy reduced the CA199 level in Chinese T2DM patients, and its greatest decrease occurred in women with longer therapeutic time. [ABSTRACT FROM AUTHOR]