Hypertension, antihypertensive agents and outcomes following renal transplantation

Hypertension is common following renal transplantation and adversely affects graft and patient survival. However, strategies for antihypertensive drug therapy and target blood pressure have not been clearly defined. Aim: To assess the influence of achieved blood pressure and antihypertension drug therapy on graft and patient survival with the aim of identifying targets and event rates for future intervention studies. Methods: We undertook a longitudinal follow up study of 634 renal transplant patients. Patients were surveyed in December 1994 and followed up after 102 months. Blood pressure (BP) was determined from the mean of three clinic readings and antihypertensive drug therapy recorded. Results: Complete follow up data were available for analysis on 622 patients (57.2% male; mean age: 45.2 +/- 13.0 yr. There were 158 (25.4%) deaths and 115 (18.5%) death-censored graft failures. Lower systolic and diastolic blood pressure were associated with better graft survival in the Kaplan-Meier analysis. Univariate analysis showed serum creatinine (HR 1.012, p < 0.001), duration of renal replacement therapy (HR 0.946, p = 0.012), age (HR 0.979, p = 0.014) and pulse pressure (HR 1.017, p = 0.044) to be predictors of graft survival with serum creatinine and duration of renal replacement therapy as the only significant factors in the multivariate analysis. Lower systolic and pulse pressure were associated with better patient survival in the Kaplan-Meier analysis. Age (HR) 1.062, p < 0.0001), serum creatinine (HR 1.002, p = 0.021), diabetes (HR 3.371, p < 0.0001), and pulse pressure (HR 1.013, p = 0.036) were significant predictors of patient survival in the univariate and multivariate analysis. Patient survival was reduced with increasing number of antihypertensives (p < 0.05), as was graft survival (p < 0.05). Reduced patient and graft survival were seen in patients prescribed calcium channel antagonists (p < 0.01). There was no increased patient mortality in those patients on beta-blockers or angiotensin converting enzyme (ACE) inhibitors. Conclusion: Hypertension is a risk factor, which remains despite the use of anti-hypertensives, for reduced patient and graft survival. The risk was not significant when blood pressure was entered together with serum creatinine in the multivariate analysis. Beta-blockers may have a beneficial effect on cardiovascular mortality, and ACE inhibitors a beneficial effect on both patient and graft survival. There is a pressing need for interventional studies to assess the impact of blood pressure targets on patient and graft survival and the effect of individual agents on these outcomes.