Kidney disease coupled with heart disease common problem in elderly

CKD is a major public health problem that disproportionately affects the elderly. Shani Shastri, MD, Mark Sarnak, MD (Tufts Medical Center), and their colleagues examined kidney and heart disease in octogenarians. The researchers assessed the prevalence of CKD by using different formulas based on different kidney function markers (serum creatinine and cystatin C) in 1,028 octogenarians enrolled in the Cardiovascular Health Study All Stars, a study of adults aged 65 years and older that examined subclinical and clinical risk factors for cardiovascular disease.

The prevalence of CKD was very high in the elderly individuals in this study. However, the study revealed that different formulas used to assess prevalence provide different pictures of CKD in the elderly. Prevalence differed from 33% to 51% depending on the equation used, even though there is a strong correlation between creatinine- and cystatin C-based estimates of kidney function. According to Dr. Sarnak, the study emphasizes that using different formulas to estimate kidney function in octogenarians results in different estimates of the prevalence of CKD. "Unfortunately, there is no gold standard estimating equation that has been developed or validated in octogenarians," he said.

Regardless of which equation researchers used to estimate kidney function, CKD in the elderly was associated with cardiovascular disease. Elderly individuals with CKD were approximately one-and-a-half to two times as likely to suffer from coronary heart disease, heart failure, or stroke as those without CKD. "Therefore, even in the very old, kidney function appears to be a marker of vascular disease," said Dr. Sarnak.

Study co-authors include Hocine Tighiouart (Tufts Medical Center); Ronit Katz, DPhil (University of Washington); Dena Rifkin, MD (University of California, San Diego); Linda Fried, MD, Anne Newman, MD (University of Pittsburgh); and Michael Shlipak, MD (University of California, San Francisco).