Multimorbidity prevalence and patterns and their associations with health literacy among chronic kidney disease patients

Background: 
Health literacy is the ability to deal with information related to one’s health. Patients with low health literacy have poor disease-management skills for chronic diseases, such as chronic kidney disease (CKD). This could influence the number and combination of their diseases.
Objective: 
To assess the association between health literacy and the prevalence and patterns of multimorbidity among CKD patients, overall and by age and sex. 
Design: 
Cross-sectional.
Participants:
We used data from the Lifelines Study, a multidisciplinary prospective population-based cohort of Dutch individuals. We included participants with CKD stages 1-5, older than 18, who reported on health literacy (n=2,742). 
Main Measures: 
Health literacy and multimorbidity, defined as having CKD and at least one comorbidity. Comorbidities related to 11 disease domains, based on data of 40 physical and psychiatric diseases. 
Key Results: 
Multinomial logistic regression showed that low health literacy was associated with a higher number of comorbidities in the crude models, and after adjustment for age, sex, eGFR, smoking, and BMI. In the crude model, the OR for low health literacy increased from 1.71 (1.25 to 2.33) for two comorbidities to 2.71 (2.00 to 3.68) for four comorbidities. In the fully-adjusted model, the associations remained significant with a maximum OR of 1.70 (1.16 to 2.49) for four comorbidities. The patterns of multimorbidity were similar for low and adequate health literacy, overall and by sex, and slightly different for patients older than 65. Older patients with low health literacy had higher comorbidity prevalence and a relatively greater share of cardiovascular, psychiatric, and central nervous system diseases. 
Conclusions: 
Among CKD patients, low health literacy is associated with more multimorbidity. Health literacy does not affect patterns of multimorbidity in younger patients, but it does slightly in older ones. Low health literacy could be an intervention target to decrease multimorbidity in CKD patients.