Numeracy Skills in CKD: Correlates and Outcomes

Background and objectives: Healthcare providers communicate the risks and benefits of treatments using frequencies, percentages, or proportions. However, many patients lack the numerical skills needed to interpret this information accurately to make informed choices. Design, setting, participants, and measurements: We assessed numeracy, the capacity to use and comprehend numbers, in a prospective cohort study of 187 patients with stage 4 to 5 chronic kidney disease or ESRD. Patients completed a three-item numeracy test and were assessed for global mental status, cognitive function, type of hemodialysis access, and kidney transplant use. We examined the association of numeracy with healthcare use and other cognitive and sociodemographic variables. Results: Over 50% of patients answered one or fewer numeracy questions correctly. Although African Americans (P = 0.0001), women (P = 0.05), and the unemployed (P = 0.0004) demonstrated lower numeracy skills, numeracy deficits were prevalent in every subgroup. In analyses adjusted for demographics and length of follow-up, higher numeracy was significantly associated with receipt of a transplant or active waiting list status. Numeracy was not associated with dialysis modality or hemodialysis vascular access. Conclusion: Similar to prior findings in the general population, these findings indicate that poor numeracy skills are very common in patients with advanced chronic kidney disease and end-stage renal disease. Additional research is needed to further explore whether poor numeracy is a barrier to receipt of a kidney transplant. Clinicians caring for patients with kidney disease should consider using tools to enhance communication and overcome limited numeracy skills. Clin J Am Soc Nephrol 5: 1566-1573, 2010. doi: 10.2215/CJN.08121109