WEST ROXBURY, MA — Individualizing hemoglobin A1c treatment goals in older adults is important to balance risks to benefits, according to a new study.
Researchers from the VA Boston Healthcare System West Roxbury Campus and Harvard University also pointed out, however, that it has not been clear whether A1c stability over time within unique target ranges has an effect on adverse outcomes.
For the report in BMJ Open Diabetes Research & Care, the study team conducted a retrospective observational cohort study from 2004 to 2016. Included were 397,634 veterans with diabetes and at least four A1c tests during a 3-year baseline. Participants had a mean age of 76.9 and underwent an average of 5.5 years of follow-up.1
The researchers created four distinct categories based on the percentage of time that baseline A1c levels were within patient-specific target ranges:
- ≥60% time in range (TIR),
- ≥60% time below range (TBR),
- ≥60% time above range (TAR), and
- a mixed group with all times <60%.
Mortality, macrovascular and microvascular complications were assessed using the categories.
Results indicated that, compared to ≥60% A1c TIR, mortality was increased with ≥60% TBR, ≥60% TAR, and the mixed group, with HRs of 1.12 (95% CI 1.11 to 1.14), 1.10 (95% CI 1.08 to 1.12) and 1.06 (95% CI 1.04 to 1.07), respectively.
“Macrovascular complications were increased with ≥60% TBR and ≥60% TAR, with estimates of 1.04 (95% CI 1.01 to 1.06) and 1.06 (95% CI 1.03 to 1.09),” the researchers advised. “Microvascular complications were lower with ≥60% TBR (HR 0.97, 95% CI 0.95 to 1.00) and higher with ≥60% TAR (HR 1.11, 95% CI 1.08 to 1.14). Results were similar with higher TIR thresholds, shorter follow-up and competing risk of mortality.
The authors concluded that, in older adults with diabetes, “mortality and macrovascular complications are associated with increased time above and below individualized A1c target ranges. Higher A1c TIR may identify patients with lower risk of adverse outcomes.”
- Conlin PR, Zhang L, Li D, Nelson RE, Prentice JC, Mohr DC. Association of hemoglobin A1c stability with mortality and diabetes complications in older adults with diabetes. BMJ Open Diabetes Res Care. 2023 Apr;11(2):e003211. doi: 10.1136/bmjdrc-2022-003211. PMID: 37024152; PMCID: PMC10083809.