By Mahboob Rahman, MD, MS

Hypertension (high blood pressure) is very common in patients with end-stage renal disease (ESRD). While most patients have high blood pressure when they start dialysis for the first time, blood pressure does improve as dialysis is performed and fluid removal is accomplished on a regular basis. However, recent data tell us that 63 percent of patients on hemodialysis in the United States remain hypertensive. Though there are many different reasons why people develop hypertension, experts believe that the inability of the kidneys to remove salt and water in patients with ESRD is the key factor.

It is important to control blood pressure because hypertension has been associated with worsening heart problems, strokes and increased hospitalizations. This is best illustrated by the experience in Tassin, France. In this dialysis center, the staff works closely with patients to get excellent blood pressure control, often to much lower levels than what is seen in other European and U.S. centers. Patients in the Tassin center live longer than those in other centers; it is thought that good blood pressure control plays an important role in achieving this.

There are several ways that patients can actively participate in controlling their blood pressure better. The first thing to keep in mind is that they should watch the amount of fluids they drink and the salt (sodium) content of the foods they eat. Since many ESRD patients have very little urine output, excessive intake of salt and fluids in between dialysis can result in large weight gains between treatments and high blood pressure. In addition, if patients gain a lot of weight in between treatments, attempts to remove it in dialysis may make the treatment uncomfortable. Dialysis unit staff have to establish a "dry weight" for patients, which is the weight at which there is no drop in blood pressure and patients have no swelling in the ankles and legs. To achieve this dry weight, staff may "challenge" the weight, meaning that they may increase the amount of fluid being removed. It is easier to keep blood pressure controlled if enough fluid can be removed each time for patients to reach their dry weight.

In summary, avoiding large weight gains, and working with the dialysis unit staff so that a correct dry weight is established are very important in achieving and maintaining blood pressure control. It is also important to remember that dry weight may need to be adjusted periodically as patients gain or lose true body weight.

Many patients will need to take medications in order to control blood pressure. It is important that patients take their medications regularly as prescribed and not miss doses. It has been shown that patients who skip or shorten dialysis treatments and miss taking medications frequently are more likely to have higher blood pressure. Many different medications are effective in lowering blood pressure; those that need to be taken only once a day are often most convenient since patients are less likely to forget taking them. Many patients will require two or more medications to control their blood pressure. A pill box, or other such aid, is often very helpful in keeping track of all the medications that need to be taken.

Finally, patients who are on peritoneal dialysis may have better blood pressure control because fluid removal occurs more gradually and over longer periods of time. Therefore, some patients may be able to tolerate fluid removal better on peritoneal dialysis than hemodialysis, allowing them to reach their dry weight and achieve better blood pressure control.

Several researchers are working to develop ways to better control blood pressure in ESRD patients; their goal is not only to lower blood pressure, but reduce the complications of hypertension such as stroke and heart disease.

References:

Mailloux LU, Levey AS. Hypertension in patients with chronic renal disease. Am J Kidney Dis. 1998 Nov;32(5 Suppl 3):S120-41

Charra B, Bergstrom J, Scribner BH. Blood pressure control in dialysis patients: importance of the lag phenomenon. Am J Kidney Dis. 1998 Nov;32(5):720-4 

Mailloux LU, Haley WE. Hypertension in the ESRD patient: pathophysiology, therapy, outcomes, and future directions. Am J Kidney Dis. 1998 Nov;32(5):705-19

Rahman M, Fu P, Sehgal AR, Smith MC. Interdialytic weight gain, compliance with dialysis regimen and age are independent predictors of blood pressure in hemodialysis patients. Am J Kidney Dis. 2000; 35(2) 257-265

Mahboob Rahman, MD, MS is Assistant Professor of Medicine in Divisions of Nephrology and Hypertension at Case Western Reserve University, University Hospitals of Cleveland and the Louis Stokes Cleveland VA Medical Center in Cleveland, OH.

This article originally appeared in the July 2002 issue of aakpRENALIFE Vol. 18, No. 1.

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