Intermediate hyperglycaemia and 10‐year mortality in resource‐constrained settings: the PERU MIGRANT Study

AIM: To determine whether intermediate hyperglycaemia, defined by fasting plasma glucose and HbA(1c) criteria, is associated with mortality in a 10‐year cohort of people in a Latin American country. METHODS: Analysis of the PERU MIGRANT Study was conducted in three different population groups (rural, rural‐to‐urban migrant, and urban). The baseline assessment was conducted in 2007/2008, with follow‐up assessment in 2018. The outcome was all‐cause mortality, and the exposure was intermediate hyperglycaemia, using three definitions: (1) impaired fasting glucose, defined according to American Diabetes Association criteria [fasting plasma glucose 5.6–6.9 mmol/l (100–125 mg/dl)]; (2) intermediate hyperglycaemia defined according to American Diabetes Association criteria [HbA(1c) levels 39–46 mmol/mol (5.7–6.4%)]; and (3) intermediate hyperglycaemia defined according to the International Expert Committee criteria [HbA(1c) levels 42–46 mmol/mol (6.0–6.4%)]. Crude and adjusted hazard ratios and 95% CIs were estimated using Cox proportional hazard models. RESULTS: At baseline, the mean (sd) age of the study population was 47.8 (11.9) years and 52.5% of the cohort were women. The study cohort was divided into population groups as follows: 207 people (20.0%) in the rural population group, 583 (59.7%) in the rural‐to‐urban migrant group and 198 (20.3%) in the urban population group. The prevalence of intermediate hyperglycaemia was: 6%, 12.9% and 38.5% according to the American Diabetes Association impaired fasting glucose definition, the International Expert Committee HbA(1c)‐based definition and the American Diabetes Association HbA(1c)‐based definition, respectively, and the mortality rate after 10 years was 63/976 (7%). Intermediate hyperglycaemia was associated with all‐cause mortality using the HbA(1c)‐based definitions in the crude models [hazard ratios 2.82 (95% CI 1.59–4.99) according to the American Diabetes Association and 2.92 (95% CI 1.62–5.28) according to the International Expert Committee], whereas American Diabetes Association‐defined impaired fasting glucose was not [hazard ratio 0.84 (95% CI 0.26–2.68)]. In the adjusted model, however, only the American Diabetes Association HbA(1c)‐based definition was associated with all‐cause mortality [hazard ratio 1.91 (95% CI 1.03–3.53)], whereas the International Expert Committee HbA(1c)‐based and American Diabetes Association impaired fasting glucose‐based definitions were not [hazard ratios 1.42 (95% CI 0.75–2.68) and 1.09 (95% CI 0.33–3.63), respectively]. CONCLUSIONS: Intermediate hyperglycaemia defined using the American Diabetes Association HbA(1c) criteria was associated with an elevated mortality rate after 10 years in a cohort from Peru. HbA(1c) appears to be a factor associated with mortality in this Peruvian population.