Pointof careHbA_1c level fordiabetesmellitusmanagement andits accuracy among tuberculosis patients: A study in four countries

BACKGROUND: Diabetes mellitus (DM) is common among tuberculosis (TB) patients and often undiagnosed or poorly controlled. We compared point of care (POC) with laboratory glycated haemoglobin (HbA_1c) testing among newly diagnosed TB patients to assess POC test accuracy, safety and acceptability in settings in which immediate access to DM services may be difficult. METHODS : We measured POC and accredited laboratory HbA_1c (using high-performance liquid chromatography) in 1942 TB patients aged ≫18 years recruited from Peru, Romania, Indonesia and South Africa. We calculated overall agreement and individual variation (mean 6 2 standard deviations) stratified by country, age, sex, body mass index (BMI), HbA_1c level and comorbidities (anaemia, human immunodeficiency virus [HIV]). We used an error grid approach to identify disagreement that could raise significant concerns. R E SULT S : Overall mean POC HbA_1c values were modestly higher than laboratory HbA_1c levels by 0.1% units (95%CI 0.1-0.2); however, there was a substantial discrepancy for those with severe anaemia (1.1% HbA_1c, 95%CI 0.7-1.5). For 89.6% of 1942 patients, both values indicated the same DM status (no DM, HbA_1c ,6.5%) or had acceptable deviation (relative difference ,6%). Individual agreement was variable, with POC values up to 1.8% units higher or 1.6% lower. For a minority, use of POC HbA_1c alone could result in error leading to potential overtreatment (n = 40, 2.1%)or undertreatment (n = 1, 0.1%). The remainder had moderate disagreement, which was less likely to influence clinical decisions. CONCLUSION: POC HbA_1c is pragmatic and sufficiently accurate to screen for hyperglycaemia and DM risk among TB patients.