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The question of whether or not glaucoma patients have an increased risk of mortality has been studied for decades with contradictory results. Lee et al. (837) examined the risk of cardiovascular mortality in glaucoma patients in the Blue Mountains Eye Study. Using Cox proportional hazards regression analysis to control for common confounding factors for mortality, the authors did not find an association between glaucoma and mortality from all-causes. While they did find a trend towards increased cardiovascular mortality risk and glaucoma, this did not reach statistical significance. Subgroup analysis found an increased relative risk of cardiovascular death in glaucoma patients under 75 years of age, but not for patients over the age of 75 years. As well, risk of cardiovascular death was increased for patients with previously diagnosed glaucoma using timolol but not for those patients not using timolol.
There is no association between glaucoma and mortality from all-causesThe strengths of this study are: 1) it is population-based with relatively long follow-up times; and 2) a clear, non-IOP dependent definition of glaucoma was used. However, there are several important limitations to the study. The most important is thatthe actual number of deaths from cardiovascular mortality is relatively small (26 in total). Because of these small numbers, it is possible that the study is underpowered to detect some relationships, such as cardiovascular risk and glaucoma without sub-classification. The authors present several non-significant trends but fail to provide a power analysis to indicate if the study was sufficiently powered to detect these differences. It is also possible that the results are due to random chance. Interestingly, the authors report that a simpler age and gender adjusted model does not show a difference in mortality risk between glaucoma patients using timolol and those not using timolol.
This study reinforces the results from the Beaver Dam Eye Study indicating that glaucoma is not associated with an overall increased mortality risk. This study also presents several tantalizing trends concerning cardiovascular mortality and glaucoma, but does not provide conclusive evidence for or against this relationship. The suggestion of increased cardiovascular mortality risk with timolol usage is again interesting and worthy of further investigation, but is not enough to change practice at this time.
(See also Lama PJ. Ophthalmology 2006; 113: 1067-1068)