Table 2. Adjusted and Unadjusted Analysis of Health Literacy Level on Number of Visits and Expenditures .
| Variable | Physician visits (SE) | Nonphysician visits (SE) | ER Visits (SE) | OFVisitsEXP (SE) | ERVisitsEXP (SE) | RxEXP (SE) |
| Unadjusted | ||||||
| Below basic or basic | 7.1 (0.2) | 5.3 (0.2) | 0.3 (0.01) | $1276 (55.4) | $152 (11.0) | $3835 (185.9) |
| Above basic | 4.2 (0.1) | 2.6 (0.0) | 0.1 (0.0) | $720 (16.9) | $99.8 (3.5) | $896 (22.5) |
| Change | +2.9 (0.2) | +2.8 (0.1) | +0.2 (0.0) | +$556 (38.5) | +$52.2 (7.5) | 2,939(163.4) |
| Adjusted | ||||||
| Below basic or basic | 6.6 (0.2) | 4.9 (0.1) | 0.2 (0.0) | $1284 (62.1) | $151 (11.3) | $3362 (167.7) |
| Above basic | 4.3 (0.1) | 2.6 (0.0) | 0.1 (0.0) | $719 (43.7) | $100 (3.4) | $910 (22.8) |
| Change | +2.3 (0.1) | +2.2 (0.1) | +0.1 (0.0) | +$565 (18.4) | +$51 (7.9) | +$2452 (144.9) |
Abbreviation: SE, standard error; ER, emergency room.
All values in table are statistically significant with P < .0001.
All results are annualized, n = 22 433 (weighted population = 500,367,522). Survey period: 2005-2008: 3 person years.
a Predicted expenditure and number of visits are adjusted for person’s type of insurance coverage and region. Visits are modeled with non-negative binomial regression. ER expenditure was modeled using Poisson family GLM with log link function. All other expenditure data were modeled using the gamma family GLM with log link function. Box-Cox and Park tests were used to determined model family and link function. Calculation of total cost and Rx expenditure due to low health literacy (LHL) as follows: Weighted population = 503 374 648; %LHL in population = 22.4% (from Table 1); Weighted LHL population = 112 755 921; per year = 37 585 307; Extrapolated visit cost = [ change (OFvisitsEXP) + change (ERvisitEXP)]*37 585 307 = $23 152 549 143; Extrapolated Rx expenditure = change (RxEXP)*37 585 307 = $92 159 172 888; US population (census.gov) = 308 745 538; Estimated LHL population = 22.4%*308 745 538 = 69 159 001; Extrapolated visit cost (adjusted for 2010 inflation) = [change (OFvisitsEXP) + change (ERvisitEXP)]* 69 159 001 = $42,601 944 315; Extrapolated Rx expenditure = change(RxEXP)* 69 159 001 = $169 577 869 255.