Hypertension and survival in chronic hemodialysis patients--past lessons and future opportunities.

There is substantial controversy surrounding the benefits of control of hypertension in hemodialysis patients. Unlike the general population, some studies suggest that higher blood pressure in hemodialysis patients offers a survival advantage, what is termed as "reverse epidemiology." To critically analyze the relationship between total and cardiovascular mortality and blood pressure, peer-reviewed, published studies in hemodialysis patients were analyzed. Consideration of the world-wide experience suggests that analysis of incident cohorts reveal a clear link between elevated blood pressure and mortality. Increased pulse pressure, which is primarily due to increased systolic pressure, is also associated with cardiovascular morbidity and mortality. The counterintuitive relationship between blood pressure and mortality appears, in part, to be due to methods of data analysis. When data are analyzed with systolic or diastolic blood pressure as separate models, not conjointly, inverse relationship between blood pressure and total and cardiovascular mortality is generally seen. When both systolic and diastolic blood pressure are considered together, systolic blood pressure or increased pulse pressure assumes a major importance in predicting cardiovascular events whereas diastolic blood pressure retains the inverse relationship. Control of hypertension in hypertensive dialysis patients is associated with improved survival. Furthermore, the use of antihypertensive drug treatment is associated with improved survival regardless of blood pressure control. Low predialysis blood pressure is associated with increased cardiovascular deaths and deaths within 2 years from malignancy or withdrawal from dialysis. These data suggest that hypertension needs to be better controlled in hypertensive hemodialysis patients. Better methods of assessment of blood pressure control, consideration of cardiac structure and function, and performance of randomized controlled trials of pharmacologic and nonpharmacologic strategies are needed to establish benefits and determining goal blood pressure in hemodialysis patients.