Work

Optimising HbA1c monitoring intervals in patients with type 2 diabetes based on glycaemic control status: a target trial emulation study

Year: 2025

Type: article

Abstract: BACKGROUND: The appropriate glycated haemoglobin (HbA1c) monitoring intervals for patients with type 2 diabetes mellitus (T2DM) remain unclear. AIM: To determine appropriate HbA1c monitoring intervals for patients with T2DM across different glycaemic control categories. DESIGN & SETTING: A target trial emulation study using electronic health records obtained from the Hospital Authority of Hong Kong and death records from the Hong Kong Government Death Registry. METHOD: Adult patients who had T2DM between 2009 and 2012 were identified and grouped by baseline HbA1c levels as follows: <7.0% (<53 mmol/mol), 7.0%-7.9% (53-63 mmol/mol), 8.0%-8.9% (64-74 mmol/mol), and ≥9.0% (≥75 mmol/mol). A pre-specified target trial was emulated for each group to evaluate the impact of various HbA1c monitoring intervals on the risk of all-cause mortality and cardiovascular disease (CVD). For HbA1c <7.0%, the following intervals were compared: every 2-4 months, 5-8 months, 9-15 months, and 16-24 months. For HbA1c ≥7.0%, comparisons were made between intervals of 2-4 months, 5-8 months, and 9-24 months. Follow-up continued until the earliest occurrence of the outcome, death, or 31 December 2021. RESULTS: The cohort comprised 183 078 patients. For those with HbA1c <7.0%, extending the HbA1c monitoring interval to every 16-24 months was not associated with higher risks of the assessed outcomes compared with intervals of 2-4 months. Among patients with baseline HbA1c 7.0%-7.9%, 9-24-month monitoring intervals versus 2-4-month intervals was associated with higher mortality risk: hazard ratio (HR) 1.10, 95% confidence interval (CI) = 1.05 to 1.15. Moreover, for those with HbA1c ≥8.0%, when compared with monitoring at 2-4-month intervals, monitoring every 5-8 months was associated with higher risk of mortality (HbA1c 8.0%-8.9%: HR 1.10, 95% CI = 1.04 to 1.16; HbA1c ≥9.0%: HR 1.25, 95% CI = 1.18 to 1.33). The corresponding HRs for CVD were 1.04 (95% CI = 0.98 to 1.10) and 1.09 (95% CI = 1.02 to 1.17), respectively. CONCLUSION: For patients with T2DM and HbA1c <7.0%, monitoring can be extended to 1.5-2 years. For those with HbA1c 7.0%-7.9% and ≥8.0%, recommended intervals are 6 months and 3 months, respectively.

Source: BJGP Open

DOI: 10.3399/bjgpo.2025.0020