The relation of ambulatory blood pressure and pulse rate to retinopathy in type 1 diabetes mellitus: the renin-angiotensin system study.
OBJECTIVE
To examine the association of ambulatory blood pressure (ABP) and ambulatory pulse rate (APR) with diabetic retinopathy (DR) in persons with type 1 diabetes in the Renin-Angiotensin System Study (RASS), a multicenter primary diabetic nephropathy (DN) prevention trial.


METHODS
Cross-sectional study.


METHODS
One hundred ninety-four normotensive RASS participants in 3 centers who are 16 years of age or older with type 1 diabetes mellitus (DM) of 2 to 20 years' duration.


METHODS
Ambulatory blood pressure and APR were monitored using standardized protocols. Patients were defined as nondippers if the night-to-day ratios for both systolic and diastolic blood pressures were >0.9. Diabetic retinopathy was determined by masked grading of 30 degrees color stereoscopic fundus photographs of 7 standard fields using the Early Treatment Diabetic Retinopathy Study severity scale.


METHODS
Severity of DR.


RESULTS
No DR was present in 32%, mild nonproliferative DR (NPDR) was present in 55%, and moderate to severe NPDR or proliferative DR was present in 13% of the cohort. Neither 24-hour systolic ABP or diastolic ABP, daytime systolic or diastolic ABP, nor nighttime diastolic ABP were related to severity of DR. Statistically significant associations were found between nighttime systolic ABP and mean ABP and DR. Among those with no DR, 19% were nondippers; for those with mild NPDR, 28% were nondippers; and for those with severe NPDR or proliferative DR, 36% were nondippers (P = 0.08). The ratio of nighttime to daytime APR, but not the 24-hour APR or daytime or nighttime APR, was related positively to the severity of DR. In multivariable analyses, only the nighttime systolic ABP was related to severity of DR (P<0.05).


CONCLUSIONS
These data suggest that ABP, especially during the night, may provide a better measure than clinical BP regarding the relationship of BP to the severity of retinopathy in normotensive persons with type 1 DM without clinical DN.
Klein
Ronald
R
Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705-2397, USA. kleinr@epi.ophth.wisc.edu
Moss
Scot E
SE
Sinaiko
Alan R
AR
Zinman
Bernard
B
Gardiner
Robert
R
Suissa
Samy
S
Donnelly
Sandra M
SM
Kramer
Michael S
MS
Goodyer
Paul
P
Strand
Trudy
T
Mauer
Michael
M
D000328:Adult; D047228:Angiotensin II Type 1 Receptor Blockers / Q000627:therapeutic use; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D003928:Diabetic Nephropathies / Q000517:prevention & control; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D004311:Double-Blind Method; D004656:Enalapril / Q000627:therapeutic use; D005260:Female; D005919:Glomerular Filtration Rate; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D019808:Losartan / Q000627:therapeutic use; D008297:Male; D012084:Renin-Angiotensin System / Q000502:physiology*
D047228:Angiotensin II Type 1 Receptor Blockers; D000806:Angiotensin-Converting Enzyme Inhibitors; D004656:Enalapril; D019808:Losartan