Kidney function declines, sometimes rapidly in older people
Physical activity can help slow the decline
Attention seniors: Chronic kidney disease is a fast-growing concern that affects about 30 percent of people over age 70. The rate of kidney function decline varies widely with age, suggesting that healthy lifestyle choices might lower the risk of kidney function decline. Researchers used data from 4,011 participants with an average of 72 years in the Cardiovascular Health Study to determine if higher levels of physical activity would reduce the rate of kidney function decline. Physical activity was evaluated in terms of self-reported 1) energy expended in physical activity per week, 2) walking pace, 3) exercise intensity, and 4) the number of blocks walked per week. A composite score of these four categories ranged from 2-8. The rate of kidney function decline dropped in a step-wise manner as physical activity increased from category 2 through 8. Greater energy expended in leisure time physical activity and greater energy intensity showed the biggest reductions in rapid kidney function decline.
Does more physical activity help Asians?
Would level of physical activity predict incident chronic kidney disease (CKD) in an Asian population? Researchers in Taiwan investigated the longitudinal association between self-reported habitual physical activity and measures of kidney function in 199,421 adults aged 20 years or older. Over a median follow-of four years, all participants underwent at least two medical examinations to determine habitual physical activity and yearly change in estimated glomerular filtration rate (eGFR)—a measure of kidney function. The average yearly decrease in eGFR in participants with baseline very low, low, moderate, and high physical activity was 0.46, 0.36, 0.30, and 0.27 mL/min/1.73 m2, respectively. Relative to participants with very low physical activity, those with low, moderate, and high-physical activity levels showed improved step-wise eGFR after controlling for a wide range of covariates. Relative to participants with very low physical activity, those who had low, moderate, and high habitual physical activity had 7, 6, and 9 percent lower risks of developing chronic kidney disease, respectively, after controlling for covariates. A higher level of habitual physical activity predicted a smaller decrease in kidney function and a lower risk of developing chronic kidney disease.
Even modest increases in physical activity can help
Longitudinal studies show that increased physical activity predicts lower risk of kidney function decline. Researchers used data from 1,199 sedentary patients (average age 79 years) in the Lifestyle Interventions and Independence for Elders Study to determine if patients assigned to a physical activity and exercise group showed better kidney function than patients in health education group after two years. Participants in the physical activity and exercise groups attended sessions twice weekly at their field center and conducted home-based strength, flexibility, and balance activities three to four times weekly for a target total time of 50 minutes per week. The health education participants attended 26 weekly, one-hour workshops then six monthly workshops. Kidney function was evaluated as the estimated glomerular filtration rate.
After two years, the physical activity group showed statistically and clinically significant slower decline in kidney function and 20 percent lower risk of rapid decline compared to the health education group. This positive result occurred despite most participants in both groups achieving low levels of physical activity. Furthermore, kidney function declined more slowly with each incremental increase in physical activity. Thus, even modest increases in physical activity produced meaningfully slower declines in kidney function. This study provides yet another reason for older people to increase their levels of physical activity, for example by walking more.
Improving kidney disease self-management
Chronic kidney disease (CKD) affects about 10 percent of the world’s humans and predisposes them to increased risk of cardiovascular disease and premature death. Health providers typically advise CKD patients to manage the disease through controlling blood pressure and blood glucose and taking medications. This approach requires self-management of diet, exercise, and medications, among other factors. Successful self-management can slow the progression of CKD and prevent complications. Alas, most patients engage in suboptimal self-management.
Researchers at the University of Pennsylvania interviewed 30 CKD patients to understand what factors related to CKD supported or thwarted successful self-management. Patients identified numerous facilitators and barriers to CKD self-management. Facilitators included a positive attitude, filling out the blood pressure chart every day, taking the family dog for daily walks, my friends at church inquiring about my health, and the doctors explaining clearly what I need to do and why. Barriers included thinking that diabetes is more important than kidney concerns, thinking that the home blood pressure machine doesn’t work properly, providers not explaining what to do and why, the gym being too far from my home, everything that’s good to eat has sodium in it, and my husband doesn’t like medical stuff lying around the house. Patient-centered interventions can promote facilitators and diminish barriers. Can you identify facilitators and barriers in your life and take action?