Purpose. The success of hypophysectomy as a treatment modality for proliferate DR correlates directly with the degree of GH deficiency achieved. The somatostatin analogue, OCT, decreases levels of growth hormone (GH) and the GH-related peptide, insulin-like growth factor-I (IGF-I). IGF-I mediates most of GH's mitogenic activity. We investigated the therapeutic efficacy of OCT in prevention of progression of DR in patients (pts) with either severe nonproliferative DR or non "high risk" proliferative DR. Methods. 16 diabetic pts were randomized to treatment (n=8)(continuous infusion or QID sub q administration of maximally tolerated OCT doses ranging from 600-3000 μg/day) or control (n=8)(conventional DM management) groups for 15 months. Pts received clinical and biochemical assessment at entry and at 3 month intervals. Ophthalmic assessment occurred at entry and at 1 month intervals. Seven fields per eye were assessed for characterization of retinopathy and grading using a modified ETDRS grading system. Results. In pts treated with OCT, GH levels (area under curve) were reduced by 33% (p<0.05), IGF-I levels were decreased by 32% (p<0.05), insulin requirements were decreased by 29% (p<0.05) and proteinuria by 82% (p<0.001). Glycemic control, as assessed by mean HgA1c, over 15 months was improved in the OCT treated group (6.4±0.9%) compared to the control group (8.1±1.2%)(p<0.05). Four pts required laser therapy in each group. No regression of DR occurred in either group. The mean time to requiring laser therapy in the control group was 6.0 months and 8.5 months in the treatment group (p=NS). While reducing GH or IGF-I levels in all pts compared to pretreatment levels, OCT therapy decreased these levels into the hypopituitary range in only one of 8 patients. This pt did not require laser therapy during the study period. Conclusions. OCT resulted in improved glycemic control and renal function. OCT plus insulin can be more effective than insulin alone in controlling diabetic hyperglycemia. Failure of OCT to eliminate the need for photocoagulation therapy in our cohort of pts is probably due to the inability of OCT to suppress GH and IGF-I levels into the hypopituitary range.
|Original language||English (US)|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - Feb 15 1996|
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience