Association of HbA1c with VO2max in Individuals with Type 1 Diabetes: A Systematic Review and Meta-Analysis

The aim of this systematic review and meta-analysis was to evaluate the association between glycemic control (HbA(1c)) and functional capacity (VO2max) in individuals with type 1 diabetes (T1DM). A systematic literature search was conducted in EMBASE, PubMed, Cochrane Central Register of Controlled Trials, and ISI Web of Knowledge for publications from January 1950 until July 2020. Randomized and observational controlled trials with a minimum number of three participants were included if cardio-pulmonary exercise tests to determine VO2max and HbAi c measurement has been performed. Pooled mean values were estimated for VO2max and HbA(1c) and weighted Pearson correlation and meta-regression were performed to assess the association between these parameters. We included 187 studies with a total of 3278 individuals with T1DM. The pooled mean HbA(1c) value was 8.1% (95%CI; 7.9-8.3%), and relative VO2max was 38.5 mL/min/kg (37.3-39.6). The pooled mean VO2max was significantly lower (36.9 vs. 40.7, p = 0.001) in studies reporting a mean HbA(1c) > 7.5% compared to studies with a mean HbA(1c) <= 7.5%. Weighted Pearson correlation coefficient was r = -0.19 (p < 0.001) between VO2max and HbA(1c). Meta-regression adjusted for age and sex showed a significant decrease of -0.94 mL /min/kg in VO2max per HbA(1c) increase of 1% (p = 0.024). In conclusion, we were able to determine a statistically significant correlation between HbAi c and VO 2max in individuals with T1DM. However, as the correlation was only weak, the association of HbA(1c) and VO2max might not be of clinical relevance in individuals with T1DM.

Automated summary

This systematic review and meta-analysis evaluated the association between glycemic control (HbA(1c)) and functional capacity (VO2max) in individuals with type 1 diabetes (T1DM). The results showed a statistically significant negative correlation between HbA(1c) and VO2max, indicating that higher HbA(1c) levels were associated with lower functional capacity. However, the correlation was weak and may not have clinical relevance in individuals with T1DM.