Low Health Literacy is Associated with the Onset of CKD during the Life Course

Abstract:

Background: 
Health literacy, the ability to deal with information related to one's health, is a predictor of health outcomes in CKD. However, research has not explored whether low health literacy predicts the onset of CKD. 
Methods: 
We used data from participants of Lifelines, a prospective population-based cohort study of individuals living in The Netherlands, to assess the share of individuals with low health literacy by eGFR category, whether low health literacy is associated with CKD onset in the general population and in the subgroup of older adults, and whether established CKD risk factors mediate this association. 
Results: 
In the total sample of 93,885 adults (mean follow-up 3.9 years), low health literacy was more likely among individuals in worse eGFR categories, increasing from 26.4% in eGFR category 1 to 50.0% in category 5 (P=0.02). Low health literacy, compared with adequate health literacy, was associated with the onset of CKD in the total sample (3.0% versus 2.1%) and in the subgroup of older adults (13.4% versus 11.3%), with odds ratios (ORs) of 1.44 (95% confidence interval (95% CI), 1.31 to 1.59) and 1.21 (95% CI, 1.04 to 1.41), respectively. After adjustment for sex, age, education, and income, health literacy was associated with CKD onset only in older adults (OR, 1.25; 95% CI, 1.04 to 1.50). This association was mediated by hypertension and high body mass index (BMI) in the crude model, but only by BMI after adjustment (with BMI explaining 18.8% of the association). 
Conclusions: 
Low health literacy is a risk factor for CKD onset among older adults, which suggests that CKD prevention might benefit from strategies to address low health literacy.