Cardiovascular disease is responsible for a majority of the medical complications (morbidity) and deaths (mortality) seen with chronic kidney disease (CKD). The risk is so high, in fact, that someone with kidney disease is more likely to die from heart disease than going on to need dialysis. For those that do make it to dialysis, their risk of dying is higher than those diagnosed with many forms of cancer.
Why You Should Know Your Risk
As pessimistic and depressing as this sounds, you have to realize that it only describes what is likely to happen to someone with kidney disease in general and not to you specifically. For example, it is not uncommon for people to live with kidney disease and on dialysis many decades. So, in order to assess your individual risk and to learn what you might be able to do to reduce it, you first need to identify your CVD risk factors (both traditional and nontraditional). Only then can you begin to address those that can be changed (i.e. modifiable risk factors).
- Having one or more risk factors doesn’t guarantee that you will develop cardiovascular disease, but it does increase your chances statistically. On the other hand, having few or no risk factors doesn’t guarantee that you won’t have a problem either.
Traditional Risk Factors
Traditional risk factors are those characteristics, diseases or conditions that indicate an increased risk for cardiovascular disease (CVD) in the general population. This typically means that they have an independent, strong, and consistent association with CVD. Most of the traditional CVD risk factors were identified by the Framingham Heart Study.- High Blood Pressure – Excess pressure strains and damages the heart and blood vessels. Extremely common in kidney disease. Most people have it by the time they start dialysis.
- Diabetes Mellitus – Accelerates the build up of fatty deposits in blood vessels (i.e. atherosclerosis). It is also the number one cause of kidney failure in the United States.
- Cholesterol Problems – Very important factor in atherosclerosis (i.e build up of fatty deposits in blood vessels). Commonly seen in people with diabetes, high blood pressure and significantly reduced kidney function. The cholesterol can be very elevated in people losing a lot of protein in their urine (i.e. nephrotic syndrome).
- Left Ventricular Hypertrophy (LVH) – Abnormal thickening of the largest and most powerful muscle (myocardium) of the heart. It is a sign of too much pressure or workload on the heart and is very common in people with kidney disease, particularly if someone is on dialysis.
Although the risk factors above are especially common in patients with kidney disease, they are by no means the only risk factors you need to be worried about. Other risk factors that may place you at significant risk involve your age, gender, heredity (i.e. race and family history), body composition (i.e. obesity), tobacco use and physical activity.
Nontraditional Risk Factors
Kidney disease and kidney-associated conditions can place you at higher risk for cardiovascular disease. Although these conditions are not as well known as other risk factors (thus nontraditional), they are increasingly being recognized for their importance.
- Chronic Kidney Disease – Kidney disease, particularly when it leads to a reduced kidney function, is starting to become appreciated as important independent risk factor for cardiovascular disease. Although the evidence is more pronounced when there is significantly reduced kidney function (GFR < 60 mL/min/m2), there is evidence suggesting early kidney disease may also pose a significant risk.
- Protein In Urine – There is a strong association between the level of protein in the urine (proteinuria) and cardiovascular disease. Part of this is due to the fact that a higher level of protein loss (i.e. overt proteinuria or nephrotic syndrome) reflects significant kidney disease. However, even a small amount of protein loss (i.e. microalbuminuria) has been shown to increase your cardiovascular risk, even if you don’t have kidney disease (i.e. general population).
In addition to all the risk factors mentioned above, advanced kidney disease is associated with a number of abnormal conditions that may increase your risk for cardiovascular disease. Some of the more important conditions involve: anemia, calcium and phosphorus, homocysteine, malnutrition, chronic inflammation or infections, oxidative stress, and uremic toxins.
Sources:
National Kidney Foundation. K/DOQI clinical practice guidelines for cardiovascular disease in dialysis patients. Am J Kidney Dis. 2005 Apr;45(4 Suppl 3):S1-153.
Weiner, Daniel and Sarnak, Mark. “Cardiovascular Disease in Patients with Chronic Kidney Disease.” Chronic Kidney Disease, Dialysis, & Transplantation 2nd Edition: A Companion to Brenner and Rector’s The Kidney. Eds. Pereira, Sayheh & Blalke. Philadelphia: Elsevier Saunders, 2005. 158-173.