Undiagnosed severe sleep apnoea and diabetic foot ulceration - a case series based hypothesis: a hitherto under emphasized factor in failure to heal.

BACKGROUND: Although great progress has been made in managing diabetic foot disease, it continues to carry significant morbidity and mortality. Obstructive sleep apnoea (OSA) and diabetes frequently coexist and recent studies suggest significant under-recognition of OSA in those with diabetes. There are no current reports on the direct clinical impact of OSA on acute or chronic diabetic foot ulcer healing. CASE REPORT: We describe three cases with Type 2 diabetes and a mean BMI of 50 kg/m(2) in whom we believe undiagnosed severe OSA may have impeded the rate of recovery of acutely infected foot ulcers. Despite standard care whilst in hospital with optimization of glycaemia, daily wound care, ulcer offloading techniques including casting, it was difficult to achieve satisfactory granulation in the first two cases with previously unrecognized and hence untreated severe OSA (Apnoea-Hypopnea Index > 30) until correction had been achieved through continuous positive airway pressure therapy (CPAP). In the third case, despite all optimization techniques, healing has not been achieved and individuals' reluctance to consider CPAP may be one possible factor. DISCUSSION: We observe in three severely obese individuals with diabetes that untreated severe OSA may have contributed to delayed wound healing. We also observed an improvement in two individuals after institution of CPAP therapy. Clinicians managing the diabetic foot should consider investigating the presence of OSA in non-healing or slowly progressive foot ulcers when all other factors have been fully optimized.

Small fibre dysfunction, microvascular complications and glycaemic control in type 1 diabetes: a case-control study.

AIMS/HYPOTHESIS: The aim of this study was to determine the influence of microvascular disease on C-fibre function in patients with type 1 diabetes of moderate duration. METHODS: The axon-reflex flare area induced on the dorsum of the foot by local skin heating to 47 °C was measured with a laser Doppler imager (LDI) in sex-, age- and height-matched groups with type 1 diabetes, with and without microvascular disease (MV+ and MV-, respectively) and in healthy controls (HC). Each group consisted of 24 individuals and all were free from clinical neuropathy (neuropathy disability score <3 and Toronto clinical neuropathy score <5). RESULTS: LDI flare (LDIflare) was reduced in MV+ compared with HC (5.1 ± 1.8 vs 10.0 ± 3.1 cm², p < 0.0001) and MV- groups (9.9 ± 2.9 cm², p < 0.0001). MV- and HC groups did not differ. There was no difference in diabetes duration between MV- and MV+ groups (17.5 ± 5.7 and 20.1 ± 5.2 years, p = 0.21) nor current HbA(1c) (MV- 8.0 ± 1.2% [64 ± 10 mmol/mol]; MV+ 8.0 ± 0.9% [64 ± 9 mmol/mol], p = 0.53); neither variable correlated with flare size. In contrast, duration-averaged HbA(1c) was higher in the MV+ group (8.6 ± 0.9% [70 ± 9 mmol/mol] vs 7.6 ± 0.6% [60 ± 7 mmol/mol], p < 0.001) and correlated with LDIflare size (r = -0.50, p < 0.001). Triacylglycerols were higher in MV+ compared with MV- (1.23 ± 0.121 vs 0.93 ± 0.7 mmol/l, p = 0.04), but other metabolic variables did not differ between the groups. CONCLUSIONS/INTERPRETATION: We have shown that glycaemic burden and the presence of microvascular complications are associated with small fibre dysfunction in type 1 diabetes.