title: Impaired reduction of nocturnal systolic blood pressure and severity of diabetic retinopathy.
abstract: The aim of the present study was to evaluate the influence of elevated levels of nocturnal blood pressure (BP) on diabetic retinopathy (DR). A total of 88 diabetic hypertensive patients were divided according to the stage of DR. They underwent 24 h ambulatory BP monitoring and ophthalmological evaluation, and their average level of fasting blood glucose as well as their glycemic control index (percentage of fasting blood glucose higher than 11.2 mmol/L over the previous four years) were calculated. When diabetic patients with retinopathy (n=29) (group 1) were compared with patients without retinopathy (n=59) (group 2), a significant difference was observed in diabetes duration (124 months [range six to 460 months] versus 43 months [range six to 365 months], respectively; P<0.05). In addition, group 1 showed higher levels of nocturnal systolic BP (NSBP) (141 +/- 22 mmHg versus 132+/-18 mmHg; P<0.05). However, no significant differences were found between the two groups (group 1 and group 2) when diurnal pressoric levels were compared (diurnal systolic BP, 153+/-19 mmHg versus 146+/-19 mmHg, P not significant; and diurnal diastolic BP, 91+/-9 mmHg versus 91+/-13 mmHg, P not significant). DR correlated with diabetes duration (r=0.26; P<0.05) and with glycemic control index (r=0.24; P<0.01). Multivariate regression analysis showed NSBP to be an independent predictor of DR (r(2)=0.12; P<0.01). Moreover, patients with severe stages of DR (preproliferative, proliferative or macular edema) showed a lower decrease of NSBP than the other patients (3.9+/-6.0 mmHg versus 9.2+/-6.0 mmHg; P<0.05). The present study suggests that the absence of 24 h normal pressoric rhythm can interfere with the prevalence and severity of DR.
authors.affiliation: Nephrology and Endocrinology Divisions, Universidade Federal do Pará
authors.forename: João Soares
authors.initials: JS
authors.lastname: Felício
authors.forename: Juliana Torres
authors.initials: JT
authors.lastname: Pacheco
authors.forename: Sandra Roberta
authors.initials: SR
authors.lastname: Ferreira
authors.forename: Frida
authors.initials: F
authors.lastname: Plavnik
authors.forename: Valdir
authors.initials: V
authors.lastname: Moisés
authors.forename: Oswaldo Kohlmann
authors.initials: OK
authors.lastname: Junior
authors.forename: Artur Beltrame
authors.initials: AB
authors.lastname: Ribeiro
authors.forename: Maria Tereza
authors.initials: MT
authors.lastname: Zanella