Optic Disc Structure and Use of Antihypertensive Medications
Optic Disc Structure and Use of Antihypertensive Medications
Purpose: To investigate the association of antihypertensive medications with optic disc structure by blood pressure (BP) level, in nonglaucoma subjects.
Design: Cross-sectional, population-based study.
Methods: A subset of Thessaloniki Eye Study participants was included in this study. Subjects were interviewed for medical history and underwent extensive ophthalmic examination, BP measurement, and optic disc imaging with the Heidelberg retinal tomograph. Subjects treated for hypertension were grouped in the following groups: (1) angiotensin-converting enzyme inhibitors and/or angiotensin-receptor blockers; (2) beta blockers and/or calcium-channel blockers; (3) diuretics alone or combined with others; and (4) other combinations. Cup size and cup-to-disc (C/D) ratio in the above groups were compared with the untreated group, using regression models. Analyses were rerun for subjects with systolic BP (SBP) < 140 mm Hg, SBP ≥ 140 mm Hg, diastolic BP (DBP) < 90 mm Hg, and DBP ≥ 90 mm Hg.
Results: Among 232 subjects, 131 were receiving antihypertensive medications. In subjects with DBP < 90 mm Hg, all medications groups were associated with larger cup size and higher C/D ratio compared with the untreated group. Results were similar in subjects with SBP < 140 mm Hg, with the exception of the beta blockers and/or calcium-channel blockers group. None of the medications groups were associated with the Heidelberg retinal tomograph parameters in those with DBP ≥ 90 mm Hg or SBP ≥ 140 mm Hg.
Conclusions: All classes of antihypertensive medications were associated with larger cup size and higher C/D ratio in subjects with either DBP < 90 mm Hg or SBP < 140 mm Hg. These results suggest that there is no specific medication-related effect on optic disc structure, and the associations found are mediated through the hypotensive effect of antihypertensive medications.
Vascular risk factors, such as systemic blood pressure (BP), ocular perfusion pressure, and nocturnal hypotension, have been implicated in the multifactorial process of open-angle glaucoma (OAG). To date, cross-sectional and longitudinal studies have been generally consistent on an association between low ocular perfusion pressure and increased OAG risk.3−12 On the contrary, the role of BP in glaucoma remains controversial. Clinic-based and population-based studies have reported a positive, negative, or no statistically significant association between high BP and OAG, whereas the 9-year incidence phase of the Barbados Eye Study and the Early Manifest Glaucoma Trial have found that low systolic BP (SBP) was a risk factor for OAG incidence and progression, respectively.
Investigating the relationship between BP and OAG is complicated by the fact that other factors interacting with BP, such as antihypertensive treatment, may be associated with glaucomatous damage. Studies that assessed the association between antihypertensive treatment and OAG have had conflicting results. In the 4-year incidence phase of the Barbados Eye Study subjects treated for hypertension had decreased risk of developing OAG, compared with subjects with untreated hypertension. However, in the Rotterdam Eye Study, the association between low diastolic perfusion pressure and increased OAG prevalence was found only in subjects treated for hypertension. On the contrary, an association between antihypertensive treatment and OAG risk was not found in the 9-year incidence phase of the Barbados Eye Study and the Singapore Malay Eye Study.
The relationship between BP and OAG becomes more complex by the fact that, for a given BP level, glaucoma susceptibility may be different in those treated for hypertension compared with nonhypertensive subjects. This is being supported by a previous Thessaloniki Eye Study report, where diastolic BP (DBP) < 90 mm Hg that resulted from antihypertensive treatment was associated with increased cupping and decreased rim area in nonglaucoma subjects, whereas no association was found in those untreated with DBP < 90 mm Hg. On the basis of these results, we suggested that BP status, meaning BP level in conjunction to the use of antihypertensive treatment, may be more relevant to glaucoma pathogenesis than BP level alone.
In addition to the above, the role of specific classes of antihypertensive medications may be an important parameter to consider,16−18 given that these are characterized by different mechanisms of actions. After our previous publication, the purpose of the present study was to examine the association of specific classes of antihypertensive medications with the optic disc structure in nonglaucomatous subjects, while taking into consideration the level of DBP and SBP.
Abstract and Introduction
Abstract
Purpose: To investigate the association of antihypertensive medications with optic disc structure by blood pressure (BP) level, in nonglaucoma subjects.
Design: Cross-sectional, population-based study.
Methods: A subset of Thessaloniki Eye Study participants was included in this study. Subjects were interviewed for medical history and underwent extensive ophthalmic examination, BP measurement, and optic disc imaging with the Heidelberg retinal tomograph. Subjects treated for hypertension were grouped in the following groups: (1) angiotensin-converting enzyme inhibitors and/or angiotensin-receptor blockers; (2) beta blockers and/or calcium-channel blockers; (3) diuretics alone or combined with others; and (4) other combinations. Cup size and cup-to-disc (C/D) ratio in the above groups were compared with the untreated group, using regression models. Analyses were rerun for subjects with systolic BP (SBP) < 140 mm Hg, SBP ≥ 140 mm Hg, diastolic BP (DBP) < 90 mm Hg, and DBP ≥ 90 mm Hg.
Results: Among 232 subjects, 131 were receiving antihypertensive medications. In subjects with DBP < 90 mm Hg, all medications groups were associated with larger cup size and higher C/D ratio compared with the untreated group. Results were similar in subjects with SBP < 140 mm Hg, with the exception of the beta blockers and/or calcium-channel blockers group. None of the medications groups were associated with the Heidelberg retinal tomograph parameters in those with DBP ≥ 90 mm Hg or SBP ≥ 140 mm Hg.
Conclusions: All classes of antihypertensive medications were associated with larger cup size and higher C/D ratio in subjects with either DBP < 90 mm Hg or SBP < 140 mm Hg. These results suggest that there is no specific medication-related effect on optic disc structure, and the associations found are mediated through the hypotensive effect of antihypertensive medications.
Introduction
Vascular risk factors, such as systemic blood pressure (BP), ocular perfusion pressure, and nocturnal hypotension, have been implicated in the multifactorial process of open-angle glaucoma (OAG). To date, cross-sectional and longitudinal studies have been generally consistent on an association between low ocular perfusion pressure and increased OAG risk.3−12 On the contrary, the role of BP in glaucoma remains controversial. Clinic-based and population-based studies have reported a positive, negative, or no statistically significant association between high BP and OAG, whereas the 9-year incidence phase of the Barbados Eye Study and the Early Manifest Glaucoma Trial have found that low systolic BP (SBP) was a risk factor for OAG incidence and progression, respectively.
Investigating the relationship between BP and OAG is complicated by the fact that other factors interacting with BP, such as antihypertensive treatment, may be associated with glaucomatous damage. Studies that assessed the association between antihypertensive treatment and OAG have had conflicting results. In the 4-year incidence phase of the Barbados Eye Study subjects treated for hypertension had decreased risk of developing OAG, compared with subjects with untreated hypertension. However, in the Rotterdam Eye Study, the association between low diastolic perfusion pressure and increased OAG prevalence was found only in subjects treated for hypertension. On the contrary, an association between antihypertensive treatment and OAG risk was not found in the 9-year incidence phase of the Barbados Eye Study and the Singapore Malay Eye Study.
The relationship between BP and OAG becomes more complex by the fact that, for a given BP level, glaucoma susceptibility may be different in those treated for hypertension compared with nonhypertensive subjects. This is being supported by a previous Thessaloniki Eye Study report, where diastolic BP (DBP) < 90 mm Hg that resulted from antihypertensive treatment was associated with increased cupping and decreased rim area in nonglaucoma subjects, whereas no association was found in those untreated with DBP < 90 mm Hg. On the basis of these results, we suggested that BP status, meaning BP level in conjunction to the use of antihypertensive treatment, may be more relevant to glaucoma pathogenesis than BP level alone.
In addition to the above, the role of specific classes of antihypertensive medications may be an important parameter to consider,16−18 given that these are characterized by different mechanisms of actions. After our previous publication, the purpose of the present study was to examine the association of specific classes of antihypertensive medications with the optic disc structure in nonglaucomatous subjects, while taking into consideration the level of DBP and SBP.