Diabetes, glycemic control and risk of medical glaucoma treatment: A population-based case-control study

PURPOSE To examine the association between diabetes and risk of medical glaucoma treatment and to assess the role of long-term glycemic control in the putative association. DESIGN Population-based case-control study. METHODS Cases of treated glaucoma were all persons filling at least three prescriptions for glaucoma medication for the first time within one year between 2001 and 2006 in Northern Jutland, Denmark. We used risk set sampling to select 10 gender- and age-matched general population controls per case using the Danish Civil Registration System. Data on diabetes, comorbidities, and laboratory tests, including glycosylated hemoglobin (as a measure of glycemic control) were obtained from population-based medical registries. We calculated odds ratio (OR) as an estimate of relative risk for treated glaucoma comparing patients with and without diabetes, adjusted for comorbid conditions and medication use. RESULTS We included 5,991 persons with incident medical glaucoma treatment and 59,910 population controls. The adjusted OR for treated glaucoma for patients with diabetes was 1.81 (95% confidence interval: 1.65-1.98). The strength of the association between diabetes and glaucoma risk did not vary by diabetes duration or by the level of glycemic control. CONCLUSIONS Regardless of glycemic control, diabetes is associated with a substantially increased risk for medical glaucoma treatment.