This is the first program-based research in Colombia reporting the association between Central Corneal Thickness and Systemic Hypertension in persons over 50.
In the present study, Patients with SH had thinner central corneal thickness ( 537.98 microns ) compared with patients without SH ( 546.57 microns ) p < 0.001 ( table 1 ). Similar to our results, A Korean study of 1259 patients concluded that Subjects with hypertension had 4.1 microns thinner CCT than those without hypertension (age, sex-adjusted, P < 0.027)(6). In contrast to these results, Wong and co-authors studied Chinese adults in a population-based cross-sectional study. In multiple regression models, CCT diminished with age (P < .001) and increased with greater Radial Corneal Curvature (P < .001) and Diabetes Mellitus (P .037), but no relationship was found with Systemic Hypertension. (7) Also, Nishituzs studied 322 Japanese adults. After multivariate adjustment, characteristics associated with increased CCT were HbA1c concentrations, diabetes, impaired glucose tolerance, body mass index, and current smoking, but no association was found with SH. (8)
The underlying mechanism for the correlation between SH and CCT remains to be determined. Our findings between thinner central corneas and the relationship with SH were consistent after age and sex adjustment, which suggests that blood pressure-lowering medication or hypertension per se may affect CCT. A thinner CCT in patients with SH may suggest a possible role as a real risk factor rather than a confounder for ocular hypertension or glaucoma.
Comparing the CCT of Hypertensive patients stratified by years of diagnosis (< 5 years, 5–10 years, > 10 years), a statistically significant tendency to have a thinner cornea was observed with a longer duration of SH. We did not find similar studies comparing these two variables, which is why we consider it a novel finding which should be considered in future population-based studies.
Our study evidenced that in multiple linear regression models adjusting for age, gender, ethnicity, IOP, and Body Mass Index, subjects with Systemic Hypertension had central corneas 7.58 microns thinner than those without SH ( table 2 ). These findings were similar to the Namil Study, where in multivariate analysis, a higher CCT(p < 0.01) was associated with a higher IOP, younger age (P < 0.001) was associated with a thinner CCT for every decade of life [95% CI 1.0–4.1 lm]). A thinner CCT (4.91 microns) was present in the presence of SH (P < 0.018) (6).
Our study's strengths are the implementation of standardized protocols from the comparable six participating cities, increasing the quality of the information. A potential weakness of our research is the study's cross-sectional design, where it is impossible to establish causal associations; also, participants were directly enrolled in SH and DM programs. Patients from these programs could represent a modified cohort due to changes in their habits and lifestyles, potentially reducing the associations of Central Corneal thickness with SH.
Conclusions: In this program-based study, we observed a strong correlation between Central Corneal Thickness and Systemic Hypertension. Considering the thinner corneas of these patients in terms of the glaucoma approach is essential.