Should CKD Be a Coronary Heart Disease Risk Equivalent?

Potential effects of reclassifying CKD as a coronary heart disease risk equivalent in the US population

BACKGROUND

Persons with chronic kidney disease (CKD) are at high risk for cardiovascular disease events, but are not classified as such in current US cholesterol treatment guidelines. We examined potential effects of modified guidelines in which CKD was considered a "coronary heart disease (CHD) risk equivalent" for risk stratification.

STUDY DESIGN

Nationally representative cross-sectional study.

SETTING & PARTICIPANTS

4,823 adults 20 years or older from the 2007-2010 National Health and Nutrition Examination Survey.

PREDICTORS

Cardiovascular risk stratification based on current US cholesterol treatment guidelines and 2 simulated scenarios in which CKD stages 3-5 or CKD stages 1-5 were considered a CHD risk equivalent.

OUTCOMES & MEASUREMENTS

Proportion of persons with low-density lipoprotein (LDL) cholesterol at levels above treatment targets and above the threshold for lipid-lowering therapy initiation, based on current guidelines and the 2 simulated scenarios.

RESULTS

Under current guidelines, 55.1 million adults in 2010 did not achieve the target LDL cholesterol goal. Of these, 25.2 million had sufficiently elevated levels to meet recommendations for initiating lipid-lowering therapy; 12.1 million were receiving this therapy but remained above goal. When CKD stages 3-5 were considered a CHD risk equivalent, 59.2 million persons were above target LDL cholesterol goals, with 28.5 million and 13.3 million meriting therapy initiation and intensification, respectively. When CKD stages 1-5 were considered a CHD risk equivalent, 65.2 million adults were above goal, with 33.9 million and 14.4 million meriting therapy initiation and intensification, respectively.

LIMITATIONS

CKD and LDL cholesterol defined using a single laboratory value.

CONCLUSIONS

Many adults in the United States currently do not meet recommended goals for LDL cholesterol levels. Modifying the current cholesterol guidelines to include CKD as a CHD risk equivalent would lead to a substantial increase in both the number of persons with levels above LDL cholesterol treatment targets and those recommended to initiate lipid-lowering therapy.

The case for chronic kidney disease, diabetes mellitus, and myocardial infarction being equivalent risk factors for cardiovascular mortality in patients older than 65 years

The objective of the study was to determine whether chronic kidney disease (CKD) is as important a risk as either diabetes mellitus (DM) or previous myocardial infarction (MI). CKD and DM are important coronary artery disease risk factors. We hypothesized that the risk of cardiovascular mortality in elderly patients with CKD is equivalent to that for patients with either DM or previous MI. The CHS limited-access database was used to identify a cohort of patients with a baseline history of MI, DM, or CKD (estimated glomerular filtration rate <60 ml/min). Subjects were categorized in 1 of 3 groups as group 1, patients with DM (no CKD or MI); group 2, patients with previous MI (no DM or CKD); and group 3, patients with CKD (no DM or MI). Patients were followed up for a mean of 8.6 years, and rates of cardiovascular mortality were compared using proportional hazards regression. There were 789, 443, and 667 people in the MI, DM, and CKD groups, respectively. During follow-up, 124 patients (15.7%) died of cardiovascular causes in the MI group, and 69 (15.8%) and 87 (13%), in the DM and CKD groups, respectively. After adjusting for age, race, gender, smoking, hypertension, and total, high-density lipoprotein, and low-density lipoprotein cholesterol, the hazard ratio (HR) for cardiovascular mortality was similar between the DM (HR 1.0, 95% confidence interval 0.8 to 1.4)) and CKD cohorts (HR 0.8, 95% confidence interval 0.6 to 1.1) compared with the MI group. In conclusion, the risk of cardiovascular mortality in patients with moderate CKD was as high as that in patients with a history of MI or DM. Designation of CKD as a cardiovascular risk equivalent in patients >65 years of age appears justified.

Evidence for a need to mandate kidney transplant living donor registries

Kidney disease is a global public health problem of growing proportions. Currently the best treatment for end-stage renal failure is transplantation. Living organ donation remains a complex ethical, moral and medical issue. It is based on a premise that kidney donation is associated with short-term minimal risks to harm the donor, and is outweighed by the definite advantages to the recipient. A growing number of patients with end-stage renal disease and shortage of kidney donors poses a pressing need to expand the criteria needed to accept kidney donors. The current donor registries are structured and are driven to expand donor pool. As living kidney donation is not without risks, more attention should be given to protect the donor health. After kidney donation, mild to moderate renal insufficiency may occur. Renal insufficiency, even mild, is associated with increased risks of hypertension, proteinuria and cardiovascular morbidity. We, therefore, foresee a need to mandate the establishment of renal transplant donor registries at all transplanting programs as a prerequisite to protect the long-term well being of kidney donors. These registries can collect the database necessary to develop standards of practice and guidelines for future kidney donation.

Development of end stage renal disease following an acute cardiac event

We determined the rate and risk factors for end-stage renal disease (ESRD) in consecutive patients discharged after a cardiac event in a large, unbiased Canadian cohort that receives universal health coverage. A total of 8236 adults hospitalized over a 2 year period were followed for up to 7.5 years and the incidence of ESRD and mortality determined. Of these, 113 reached ESRD (stage 5). Patients with moderate (stage 3) and severe (stage 4) renal insufficiency were more likely to develop ESRD than those patients at stage 1 or 2. However, patients with moderate renal insufficiency were 78.6 times more likely to die than to develop ESRD. Absolute rates of progression to ESRD per 100-patient years were 0.08 at stages 1 and 2, 0.17 at stage 3 and 4.27 at stage 4. Age, diabetes, hypertension and congestive heart failure also predicted ESRD. We found that patients with stage 4 disease are at high risk of ESRD after a cardiac admission while those at stage 3 are far more likely to die than to develop ESRD.

Lipid abnormalities and cardiovascular risk in renal disease

The recent 4D study failed to provide definitive evidence for benefit of statin use in type 2 diabetics on dialysis. This finding stands in stark contrast to a number of other observations in patients with early stages of chronic kidney disease where substantial benefit of statins had been documented. Here we discuss some potential explanations for the unexpected finding of the 4D study and for the negative association between below average total cholesterol and vascular mortality among dialysis patients. Admittedly, in the absence of definite evidence in dialysis patients, we still conclude that the administration of statins is appropriate in patients with manifest coronary disease.