Improving T2DM Detection Using Spot cHbA1c Test

Objectives: To evaluate the effectiveness of active opportunistic screening using point-of-care capillary Hemoglobin-A1c (POC-cHbA1c) testing, compared to venous HbA1c (vHbA1c) testing, in improving detection of type 2 diabetes mellitus (T2DM) among at-risk primary care patients. Design: Pragmatic cluster randomized controlled trial. Setting: 8 public primary care clinics in Hong Kong. Participants: A minimum of 776 patients (97 per clinic) who have ≥1 risk factor for T2DM, but no known diagnosis of DM or DM screening in the past 12 months. Intervention: Participants at intervention clinics (n=4) will be offered free POC-cHbA1c testing on-site, immediately informed of test results and DM risk, and scheduled for confirmatory oral glucose tolerance test (OGTT) if screened positive (i.e. HbA1c≥5.6%). Participants at control clinics will be offered free vHbA1c testing scheduled on a separate day, informed of test results and DM risk via phone, and scheduled for confirmatory OGTT if screened positive. Main outcome measures: Primary outcomes are uptake rate of POC-cHbA1c versus vHba1c testing, and difference in proportion of T2DM detected between intervention and control groups. Secondary outcomes include number-needed-to-screen to detect one more T2DM case. Data analysis: Participants' characteristics and test uptake rates will be summarized by descriptive statistics. Difference in the proportion of T2DM detected between groups will be compared using Chi-squared test. Number-needed-to screen to identify one additional patient with DM will be calculated. Expected results: A greater proportion of T2DM patients will be detected by POC-cHbA1c than vHbA1c due to a higher screening test uptake rate among the studied population.