Association of mean ocular perfusion pressure and diabetic retinopathy in type 2 diabetes mellitus: Sankara Nethralaya diabetic retinopathy epidemiology and molecular genetic study (SN-DREAMS, Report 28).

PURPOSE

To elucidate the distribution of mean ocular perfusion pressure (MOPP) and to study the relationship between MOPP and diabetic retinopathy (DR) in a south Indian subpopulation with diabetes.

METHODS

This study was a population-based, cross-sectional evaluation of 1368 subjects, aged ≥40 years, with type 2 diabetes. DR was diagnosed on the basis of the modified Klein classification. Systolic and diastolic blood pressure (SBP and DBP) were recorded with a mercury sphygmomanometer. Intraocular pressure (IOP) was assessed by applanation tonometry. MOPP was derived by the formula: MOPP = 2/3;[DBP + 1/3;(SBP - DBP)] - IOP.

RESULTS

The mean ± SD for MOPP was 52.6 ± 9.0 mm Hg, higher in the women than in the men (P = 0.046). In comparison to subjects without DR, MOPP was higher in the men with sight-threatening DR (STDR) (P = 0.030) and higher in women with any DR (P = 0.008) and non-STDR (P = 0.006). However, on multivariate analysis after adjustment for all factors, MOPP was found not to be associated with DR (OR = 1.02, 95% CI = 0.99-1.03; P = 0.149), non-STDR (OR = 1.02, 95% CI = 0.99-1.03; P = 0.312), or STDR (OR = 1.02, 95% CI = 0.98-1.05; P = 0.358).

CONCLUSIONS

Univariate analysis revealed very small differences in the association of MOPP and DR in both sexes which are probably of no clinical significance. Multivariate analysis showed no association between MOPP and DR. There seems to be very little evidence of a link between MOPP and DR. It may be more informative to evaluate the association in longitudinal studies.