Objective: In the general population, a low ankle-brachial index (ABI) (<0.9) is strongly associated with (cardiovascular) mortality. However, the association between the ABI and mortality may be weaker in individuals with diabetes, as ankle pressures may be elevated by medial arterial calcification and arterial stiffening, which occur more frequently in diabetes. Therefore, the aim of this study was to compare the association between ABI and mortality in individuals without and with diabetes.
Research design and methods: We studied the associations between ABI and cardiovascular and all-cause mortality in 624 individuals from the Hoorn study, a population-based cohort of 50- to 75-year-old individuals (155 with diabetes and 469 without) followed for a median period of 17.2 years. Data were analyzed using Cox proportional hazards models.
Results: During the follow-up period, 289 of 624 (46.3%) participants died (97 of 155 with and 192 of 469 without diabetes and 52 of 65 with and 237 of 559 without ABI <0.9): 85 (29.4%) of CVD (30 of 155 with and 55 of 469 without diabetes and 20 of 65 with and 65 of 559 without ABI <0.9). A low ABI was strongly associated with cardiovascular mortality (relative risk 2.57 [95% CI 1.50-4.40]) and all-cause mortality (2.02 [1.47-2.76]), after adjustment for Framingham risk factors. The associations of the ABI with mortality did not differ between individuals without and with diabetes for cardiovascular (P(interaction) = 0.45) or all-cause (P(interaction) = 0.63) mortality.
Conclusions: In the Hoorn Study, associations between ABI and cardiovascular and all-cause mortality were similar in individuals without and with diabetes. Future studies should investigate, in both individuals without and with diabetes, whether measurement of ABI can be used to guide treatment decisions.