The ratio of fasting plasma glucose to hemoglobin A1c as a predictor of all-cause mortality in individuals with normal glucose levels: The Jichi Medical School cohort study

OBJECTIVES: The fasting plasma glucose/hemoglobin A1c ratio is considered a marker associated with glucose metabolism disorders, including fasting hyperglycemia. However, it remains unclear whether this ratio can be used for the prevention of deaths in individuals with normal fasting plasma glucose levels. This study aimed to see the predictive value of the fasting plasma glucose/hemoglobin A1c ratio for all-cause mortality in a general population with normal fasting plasma glucose levels. METHODS: The study investigated prospectively a cohort of 1087 multi-regional, community-dwelling Japanese participants (women, 69.2%) for a follow-up period of 11.3 years. We included individuals with fasting plasma glucose levels <6.11 mmol/L and excluded those meeting the diabetes criteria. All-cause mortality was the primary outcome and hazard ratios were calculated using the Cox proportional hazard model after dividing the fasting plasma glucose/hemoglobin A1c ratios into tertiles. RESULTS: There were 54 deaths (25 women) during the follow-up period. The high tertile group had a significantly higher hazard ratio for all-cause mortality than the low tertile group in women (multivariate-adjusted hazard ratio = 4.45; 95% confidence interval = 1.26–15.72), but not clearly in men. CONCLUSION: The data of the population-based cohort study suggest that a high fasting plasma glucose/hemoglobin A1c ratio can predict all-cause mortality in women with normal fasting plasma glucose levels.