Difficulty including subjects corresponding to the criteria.

Sleep apnea syndrome (SAS) is a common comorbidity of type 1 and type 2 diabetes. A low transcutaneous oxygen tension (PtcO2) measured on the foot is pejorative prognostic factor for the healing of a diabetic foot wound. SAS causes intermittent nocturnal hypoxia and sympathetic overactivity. The investigators hypothesized that SAS could be a factor reducing the PtcO2.Therefore, the main objective of this study is to assess the variation in PtcO2 between the end of the night and midday in patients with -or at risk of- diabetic foot wound according to the presence or not of sleep apnea syndrome.The secondary objective is to address the microvascularisation of diabetic patients having foot wounds according to their status regarding sleep apnea syndrome.

The study is observational, cross-sectional. Presence of sleep apnea syndrome will be assessed on the same night than the main outcome, that is the difference in PtcO2 between 5:00 AM and 12:00AM. Microvascularisation will be assessed by Laser Speckle Contrast Imaging Analysis (LASCA).

Sample size is estimated at 60 patients based on previous revascularisation studies having PtcO2 as main outcome.

An intermediary analysis is planned after 40 inclusions.

Inclusion Criteria:

• Types 1 or 2 or MODY diabetes with diabetic foot wound (or at risk of foot wound stage 2 and 3 (see reference PMID:18442189).
• Patients covered by social insurance

Exclusion Criteria:

• Patients with sleep apnea syndrome previously treated by positive airway pressure therapy.
• Patients previously treated by additional oxygen therapy. Patient with unstable psychiatric disease

Consecutives diabetic patients referred to our tertiary diabetes unit (Grenoble University Hopsital, France) for diabetic foot wound