Self-reported inactivity is associated with faster decline in kidney function in American Indians with chronic kidney disease

INTRODUCTION:Individuals with chronic kidney disease (CKD) are less active than their non-CKD counterparts. Few studies have examined the effects of inactivity on CKD progression. The purpose of this analysis was to examine the association between baseline leisure time physical activity (LTPA) and change in kidney function in American Indians (AI) with CKD. METHODS: The Strong Heart Study is a longitudinal study of CVD and its risk factors in 4,549 AIs, aged 45-74 years, from 13 U.S. communities. Individuals were categorized based on their self-reported baseline LTPA levels (no activity, low and high activity). The MDRD formula was used to estimate glomerular filtration rate (eGFR) at baseline and five year follow-up. CKD was defined as an eGFR <60mL/min. Multivariate logistic regression was used to examine the relationship between LTPA and rapid decline in kidney function (>3ml/min per year). RESULTS: CKD was prevalent in 10.5% of the population at baseline (N=458) with 29%, 36%, and 35% reporting no, low, and high levels of LTPA respectively. Compared to highly active individuals, low and inactive individuals had a 2.96 odds (95% CI: 0.93, 9.43) and 3.92 odds (95% CI: 1.16, 13.30) of experiencing rapid declines in kidney function independent of baseline age, eGFR, albuminuria, gender, diabetes and hypertension. CONCLUSION: This was the first study to examine the relationship between activity and change in kidney function in AI's with CKD. Individuals who reported no LTPA at baseline had faster progression of CKD. Future studies should determine whether increasing activity levels slows progression of CKD.