title: Hypoglycaemia is associated with the absence of a decrease in diurnal macular thickness in patients with diabetic macular oedema.
abstract: OBJECTIVE
  Spontaneous diurnal variations measured by optical coherence tomography (OCT) have been reported in diabetic macular oedema (DME) together with a daytime decrease in central macular thickness (CMT). For this reason, this study aimed to investigate the influence of acute glucose and blood pressure changes on daytime variations in CMT in patients with DME.
  
  
  METHODS
  In this prospective observational study of type 1 (n=4) and type 2 (n=18) diabetic patients with DME, OCT scans, capillary blood glucose, and systolic and diastolic blood pressure measurements were performed at 9 a.m., 12 a.m., 3 p.m., 6 p.m. and again at 9 a.m. the day after. At the same time, the study protocol included simultaneous ambulatory blood pressure and glucose monitoring over a 24-h period. Hypoglycaemic episodes, defined as glucose values<60mg/dL, were also recorded.
  
  
  RESULTS
  CMT decreased consistently between 9 a.m. and 6 p.m. in 10 patients (from 374±82μm to 337±72μm; P=0.01) and increased or remained steady in 12 others (from 383±136μm to 390±149μm; P=0.58), with a significant difference in CMT absolute change between the two groups (P<0.001). In the study population as a whole, the lower the mean diurnal blood glucose, the smaller the decrease in CMT during the day (P=0.027). Also, eight (67%) of the 12 patients with a flat CMT profile experienced a diurnal hypoglycaemic event whereas none of those with a CMT decrease had hypoglycaemia (P=0.002).
  
  
  CONCLUSIONS
  Hypoglycaemic events may explain the lack of diurnal CMT decrease in diabetic patients with DME. However, further studies need to be conducted to evaluate whether having no diurnal CMT decrease is associated with a poorer visual prognosis and whether it can be modified by better glucose control.
authors: Service de Médecine Interne, CHNO des Quinze-Vingts, Paris, France. s.feldman@quinze-vingts.fr
authors: S
authors: S
authors: Feldman-Billard
authors: B
authors: B
authors: Dupas
authors: N
authors: N
authors: Sedira
authors: J
authors: J
authors: Bitu
authors: A
authors: A
authors: Erginay
authors: P J
authors: PJ
authors: Guillausseau
authors: P
authors: P
authors: Massin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D003922:Diabetes Mellitus, Type 1 / Q000150:complications; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003930:Diabetic Retinopathy / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D005602:France / Q000453:epidemiology; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007003:Hypoglycemia / Q000097:blood / Q000150:complications* / Q000453:epidemiology; D008269:Macular Edema / Q000097:blood / Q000150:complications / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012160:Retina / Q000503:physiopathology; D041623:Tomography, Optical Coherence; D042461:Vascular Endothelial Growth Factor A / Q000097:blood
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D042461:Vascular Endothelial Growth Factor A; C467484:VEGFA protein, human; C517652:hemoglobin A1c protein, human