A total of 7,471 enrollees were contacted by telephone 3 months after they enrolled in Prudential HealthCare. Of these, 3,390 refused to participate, 737 did not meet eligibility criteria, and 3,344 completed the in-home interview. A total of 84 individuals were excluded because they did not complete the S-TOFHLA, leaving 3,260 participants available for analysis. Nonresponders were more likely to be age 85 or older (7.5% vs 5.4%) and more likely to be male (45.2% vs 42.6%). Nonresponders also lived in ZIP code areas with a higher median per capita income (27.8% lived in an area with a median per capita income of greater than $17,842 per year vs 10.7% of responders) and higher educational attainment.
Among participants, individuals with inadequate health literacy were older, more likely to be nonwhite, and had lower income and education than individuals with adequate health literacy (). They were less likely to have ever smoked cigarettes, less likely to have used alcohol during the past month, and their health status was worse than those with adequate health literacy ().
Participant Characteristics by Literacy Level According to the Short Test of Functional Health Literacy in Adults
The risk of having no physician visit during the first year after enrollment was similar for participants with adequate (8.1%), marginal (9.3%), and inadequate functional health literacy (9.8%; ). The results were unchanged in multivariate analysis (). The time to first outpatient visit was also similar based on Kaplan-Meier curves () and multivariate Cox proportional hazards models ().
Outpatient Physician Visits During the Year After Enrollment by Functional Health Literacy Level
FIGURE 1 Kaplan-Meier curves for the proportion of participants remaining enrolled without a physician outpatient visit for those with adequate (solid line) and inadequate literacy (dashed line). Individuals with marginal literacy had a similar survival curve (more ...)
Among patients with at least 1 outpatient physician visit (N = 2,978), the mean number of visits over the first year was 13.7 (95% confidence interval [CI], 13.0 to 14.3) for participants with adequate health literacy, 14.0 (95% CI, 12.4 to 15.5) for those with marginal health literacy, and 15.3 (95% CI, 14.2 to 16.3) for those with inadequate health literacy. The median number of visits was 9 for those with adequate health literacy, 8 for those with marginal health literacy, and 9 for those with inadequate health literacy. After adjusting for the worse health status of participants with limited health literacy and the other covariates listed above, participants with marginal health literacy averaged 0.80 fewer visits (95% CI, −2.41 to 0.82), and those with inadequate health literacy averaged 0.59 fewer visits (95% CI, −1.91 to 0.72) than participants with adequate health literacy (). The results were similar when we used a natural logarithm transformation of the number of visits as the dependent variable ().
Participants with inadequate health literacy and marginal health literacy were more likely to have an ED visit than participants with adequate health literacy (30.4%, 27.6%, and 21.8%, respectively; P = .01 and P < .001 for comparison to those with adequate health literacy, respectively; ). Almost all of this difference was due to the proportion of participants with 2 or more ED visits (13.4%, 12.3%, and 6.8%, respectively; P < .001 for both compared to those with adequate health literacy; ). In multivariate analysis (with a polytomous outcome of 0, 1, or ≥2 visits), the risk of having 2 or more ED visits was 1.44 (95% CI, 1.01 to 2.02) for those with marginal health literacy and 1.34 (95% CI, 1.00 to 1.79) for those with inadequate health literacy compared to participants with adequate health literacy (). The adjusted risk of having a single ED visit was 1.01 (95% CI, 0.76 to 1.33) for those with marginal health literacy and 1.07 (95% CI, 0.86 to 1.33) for those with inadequate health literacy compared to participants with adequate health literacy ().
FIGURE 2 Percentage of participants with 1 ED visit (dark gray) and 2 or more ED visits (light gray) in the year after enrollment by literacy level. Emergency department visits included all visits within 12 months of enrolling in the managed care plan. Visits (more ...)