Glycaemic control of Asian patients with type-2 diabetes mellitus on tiered up-titration of metformin monotherapy: A one-year real-world retrospective longitudinal study in primary care

To determine the glycaemic control and associated factors among patients with type-2 diabetes mellitus on tiered metformin monotherapy over one-year.Adult Asian patients on metformin monotherapy with tiered dosage up-titration (low < 500 mg/day; medium 500-<1000 mg/day and high ≥ 1000 mg/day) are divided into four sub-cohorts based on their baseline HbA1c < 7%(C<7); 7%-<8%(C7-<8); 8%-<9%(C8-<9) and ≥ 9%(C≥9). The HbA1c absolute reduction, time to reach glycaemic control (HbA1c < 7%), and time from glycaemic control to failure (HbA1c ≥ 7%) after the dosage up-titration were the outcomes.Among 5503 eligible patients (mean age = 64.9 years, 45.6% males and 74.6% Chinese), the HbA1c absolute reduction after the up-titration at three months are 0%, 0.4%-0.6%, 0.8%-1.2% and 2.0%-2.1% for C<7, C7-<8, C8-<9 and C≥9 respectively. The median time (months) to attain glycaemic control for low, medium and high dosage up-titration were 4, 3, 3(C7-<8); 12, 7, 4(C8-<9); NA, 7, 7(C≥9). Within twelve months after the goal attainment, 36.2%(C<7), 48.8%(C7-<8), 52.7%(C8-<9) and 45.3%(C≥9) of patients had treatment failure.The results show that the baseline HbA1c and tiered metformin dosage up-titration are associated with disproportionate HbA1c reduction, time to glycaemic control and time from glycaemic control to failure.