Insights from ambulatory blood pressure monitoring: diagnosis of hypertension and diurnal blood pressure in renal transplant recipients.
BACKGROUND
Accurate diagnosis of hypertension is essential in chronic kidney disease patients, as it is linked to increased left ventricular mass, stroke, cardiovascular mortality and morbidity, and progression to end-stage renal disease. Elevated blood pressure (BP) detected by ambulatory BP monitoring (ABPM) has been shown to be predictive of worse outcome in chronic kidney disease patients. Another predictor of worse outcome is diurnal BP variation, measured also by ABPM. In this study, the authors examined the relationship (concordance or discordance) between blood pressure measured by ABPM compared with daytime office BP, and also explored the predictors of diurnal variation in renal transplant recipients.


METHODS
All the patients who underwent renal transplantation and follow-up at the authors' institution from January 1998 to January 2003 were involved in this study (n=177) in addition to another randomly selected 64 patients that underwent transplantation before 1998. All patients had their ABPM performed according to previously described protocols at least 2 weeks after discharge from the hospital, dialysis-independent and with a functioning renal allograft.


RESULTS
The authors found a positive correlation between systolic BP (SBP) diurnal variation and age (r =0.263, P <0.0001), glomerular filtration rate (GFR) (r =-0.229, P <0.0001), cyclosporine trough (r =0.171, P =0.047), and ABPM-to-transplant interval (r =-0.133, P =0.039). After fitting a regression model, the authors found that only GFR (P <0.0001) and age (P =0.001) were independent predictors of SBP diurnal variation (r =0.357). Concordance rate between casual BP and ABPM was 80%, and by using casual BP, only 15% of hypertensive renal transplant patients would be erroneously diagnosed as normotensive.


CONCLUSIONS
The authors found that SBP diurnal variation is predicted independently by age and GFR, although it does correlate with cyclosporine trough and ABPM-to-transplant interval. In addition, the authors showed that ABPM is a more sensitive method for diagnosing hypertension than is sole reliance on office BP in renal transplant recipients.
Haydar
Ali A
AA
Renal and Transplantation Unit, Guy's Hospital, London, United Kingdom.
Covic
Adrian
A
Jayawardene
Satish
S
Agharazii
Mohsen
M
Smith
Eilish
E
Gordon
Isabel
I
O'Sullivan
Helen
H
Goldsmith
David J A
DJ
D018660:Blood Pressure Monitoring, Ambulatory / Q000379:methods*; D002940:Circadian Rhythm / Q000502:physiology*; D016572:Cyclosporine / Q000493:pharmacokinetics / Q000627:therapeutic use; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D006973:Hypertension / Q000175:diagnosis* / Q000503:physiopathology; D007166:Immunosuppressive Agents / Q000493:pharmacokinetics / Q000627:therapeutic use; D016030:Kidney Transplantation / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012189:Retrospective Studies; D013599:Systole; D016896:Treatment Outcome
D007166:Immunosuppressive Agents; D016572:Cyclosporine