Impact of HbA1c, followed from onset of type 1 diabetes, on the development of severe retinopathy and nephropathy: the VISS Study (Vascular Diabetic Complications in Southeast Sweden).

OBJECTIVE: HbA1c is strongly related to the development of diabetes complications, but it is still controversial which HbA1c level to strive for in the treatment of type 1 diabetes. The aim of the current study was to evaluate HbA1c, followed from diagnosis, as a predictor of severe microvascular complications and to formulate HbA1c target levels for treatment. RESEARCH DESIGN AND METHODS: A longitudinal observation study followed an unselected population of 451 patients diagnosed with type 1 diabetes during 1983-1987 before the age of 35 years in a region of Southeast Sweden. Retinopathy was evaluated by fundus photography and nephropathy data collected from medical records. HbA1c was measured starting from diagnosis and during the whole follow-up period of 20-24 years. Long-term weighted mean HbA1c was then calculated. Complications were analyzed in relation to HbA1c levels. RESULTS: The incidence of proliferative retinopathy and persistent macroalbuminuria increased sharply and occurred earlier with increasing long-term mean HbA1c. None of the 451 patients developed proliferative retinopathy or persistent macroalbuminuria below long-term weighted mean HbA1c 7.6% (60 mmol/mol); 51% of the patients with long-term mean HbA1c above 9.5% (80 mmol/mol) developed proliferative retinopathy and 23% persistent macroalbuminuria. CONCLUSIONS: Long-term weighted mean HbA1c, measured from diagnosis, is closely associated with the development of severe complications in type 1 diabetes. Keeping HbA1c below 7.6% (60 mmol/mol) as a treatment target seems to prevent proliferative retinopathy and persistent macroalbuminuria for up to 20 years.

The frequency of amblyopia among visually impaired persons.

PURPOSE: To investigate the frequency of amblyopia among visually handicapped patients. METHODS: The study is a retrospective investigation of all living patients registered in four Visual Rehabilitation Centres in a region in southern Sweden. The area's total population numbered 865,612 persons of whom 11,365 were registered as visually handicapped (with visual acuity < or = 0.3 in the better eye). RESULTS: Amblyopia was the main cause of decreased visual acuity in one eye in 1.72% (195 of 11,365) of the patients. The average age of the patients with amblyopia was 69 years (9-95 years) and 28.2% of these patients were less than 65 years old (the age for retirement in Sweden). The median visual acuity in the amblyopic eye among these patients was 0.1. The median visual acuity in the nonamblyopic eye was 0.2. The most common cause of decreased vision in the nonamblyopic eye was macular degeneration (39.5%). Bilateral amblyopia was present in 13 (6.7%) of the amblyopic patients. By comparing this study with earlier studies, we can calculate that about 1.2% of the persons with amblyopia 0.3 or lower will eventually become visually handicapped. CONCLUSION: A small but considerable number of patients who attend the Visual Rehabilitation Centres have amblyopia as a cause of their visual impairment. Since amblyopia can be treated if detected in childhood, later visual rehabilitation of these patients can be avoided or delayed, thereby reducing rehabilitation costs for society.