Retinopathy and Visual Acuity in People with Diabetes Mellitus and Hard to Heal Diabetic Foot Ulceration
The prevalence of diabetes mellitus and its complications are increasing worldwide. Two of the complications:foot ulceration and diabetic retinopathy are especially feared, the former because of the risk of amputation and possible death, the latter because of the risk of.becoming blind The life time risk of developing a foot ulcer is estimated to be up to 25% The world wide prevalence of any diabetic retinopathy is 34,6 .6.7 for proliferative retinopathy, 6.8 for macular edema and for vision threatening retinopathy 10.2 During the first twenty years of disease retinopathy develops in most patients with Type 1 diabetes and in over 60% in Type 2 Any degree of retinopathy augments all case mortality more than 2.3 fold inType 1 diabetes and more than 2.4 in Type 2. Foot ulcers increase mortality by 2.5 compared to diabetic patients without ulcerations. Also lowered visual acuity increases mortality. In the feet neuropathy, somatic and autonomous, and periferal vascular disease lead to altered blood flow and ischemia. Repetitive trauma then greatly increase the risk of ulceration Some of the ulcers are hard to heal and are therapeutic challenges where Hyperbaric oxygen therapy as an adjunct have been used. Its effects on diabetic eyes are incompletely known. In the first paper we described the rationale of hyperbaric oxygen therapy and designed a study with so few weak points as possible. People with chronic diabetic foot ulcers were to be treated in an hyperbaric chamber with high pressure oxygen (2.5 ATA) or placebo Treatment is given in a double blinded, randomised, prospektive way. Follow up time of ulcers and eye is two years. In paper two we measured transcutaneous oxygen of the feet to compare these values with the thickness of the retina, as increased retinal thickness is a sign of retinal vasculopathy. Low O2 values of the feet covariated with thicker retina. Several studies have shown improved healing of chronic diabetic ulcers by hyperbaric oxygen treatment. In paper three we report on a prospektive, randomised and double blinded study, where people with chronic ulcers were treated with hyperbaric oxygen or placebo (hyperbaric air) at 2.5 ATA for 40 sessions and then were followed for two years with fundus photography and visual acuity measuring. We found the high pressure oxygen treatment ophtalmological neutral except for a transient drop of acuity after 3 months in the oxygen but not placebo group. In the fourth paper we compared two matched groups, one with chronic diabetic foot ulcers, one without. The. ulcer group had more severe retinopathy, more proliferative changes, more macular edema and lower visual acuity. The group differences also remained in insulin treated people and in people with kidney disease. In paper five we followed the groups above for five and ten years for retinopathy, visual acuity and mortality. DR increased with diabetes duration and was more frequent and severe in the ulcer group. In the ulcer group visual acuity went from 10% severe visual impairment to 15.6% after 5 years and to 15.4% after ten years.This seems to depend on high mortality in the PDR group. Corresponding values in the non ulcer group were 0.6% 0.8% and 4.8% Presence of any DR increased 10 year mortality 1.91 times in the ulcer group and 1.70 times in the control group. In paper six we studied 5 year mortality in people with and without foot ulceration and visual acuity <6/12 (logMAR <0.3).The mortality was significantly higher in people with impaired vision, but worst in the ulcer group. Significant predictors of mortality were: DFU( RR 3.6) male sex (RR 2.34) Visual impairment (RR 1.77) age (RR 1.48) and low eGFR (RR 1.42)