Relationship between cognitive function in individuals with diabetic foot ulcer and mortality

Background Diabetic foot ulcer (DFU) is a common diabetes mellitus (DM) complication. Individuals with DM and a DFU achieved significantly lower scores in cognitive tests than those without a DFU. We investigated whether baseline cognitive function in individuals with a DFU is a determinant of mortality. Methods A prospective study using data collected during a case-control study conducted in 2010-2012 whereby 90 participants with a DFU (mean age at baseline 58.28 +/- 6.95 years, 75.6% male) took the paper and pencil and the NeuroTrax battery of cognitive tests. Depression was assessed, and the DFU status was evaluated. In 2020, information pertaining to participants' vital status (dead/alive) was collected and the relationship between baseline cognitive status and vital status was assessed. Results During a median follow-up of 6.8 years (range 0.2-9.5), 39 participants died (43.3%). Individuals alive vs. those who had died during follow-up had a higher global cognitive score at baseline (92.16 +/- 10.95 vs. 87.18 +/- 12.24, p = 0.045), but increased risk was not found. Individuals who were alive vs. those who had died during follow-up had statistically significantly higher baseline executive function, reaction time and digit symbol substitution test results. However, after adjustment for glycosylated hemoglobin (HbA1c), microvascular and macrovascular complications, no relationship between cognitive tests and mortality remained significant. Conclusions The higher mortality rate among people with type 2 DM and a DFU was not significant after adjustment for HbA1c, micro- and macrovascular complications. There may be common pathophysiological pathways to both DM complications and cognitive impairment, which may contribute to increased mortality. Further studies are warranted.