Table 2.
Effect of Exceeding Spending Cap on Monthly Drug Spending, Number of Prescriptions, and Percentage Generic Utilization by Cohort (Standard Errors in Parentheses)
| Number of Prescriptions |
Spending |
Proportion Generic |
|||||
|---|---|---|---|---|---|---|---|
| Cohort Descriptors | Marginal Effect of Cap | Percent Change | Price Elasticity of Demand | Marginal Effect of Cap | Percent Change | Marginal Effect of Cap | Percent Change |
| Overall | −0.84 | −14.28 | −0.12 | −$50.65 | −18.89 | 0.017 | 4.19 |
| (0.01) | (0.18) | ($0.57) | (0.21) | (0.001) | (0.21) | ||
| First month spending | |||||||
| Lowest quartile | −0.26 | −6.00 | −0.05 | −$7.96 | −4.72 | 0.008 | 1.86 |
| (0.02) | (0.50) | ($1.12) | (0.66) | (0.002) | (0.51) | ||
| Second quartile*,†,‡ | −0.57 | −11.37 | −0.10 | −$31.98 | −15.07 | 0.015 | 3.71 |
| (0.02) | (0.36) | ($0.89) | (0.42) | (0.002) | (0.42) | ||
| Third quartile*,†,‡ | −0.81 | −13.57 | −0.12 | −$48.52 | −17.92 | 0.020 | 5.02 |
| (0.02) | (0.31) | ($0.96) | (0.36) | (0.001) | (0.38) | ||
| Highest quartile*,†,‡ | −1.71 | −20.94 | −0.18 | −$114.16 | −27.04 | 0.024 | 6.33 |
| (0.02) | (0.31) | ($1.51) | (0.36) | (0.001) | (0.38) | ||
| Chronic disease cohort | |||||||
| Did not have one of 5 chronic disease diagnoses in 2001 | −0.76 | −15.34 | −0.13 | −$53.45 | −22.17 | 0.019 | 4.99 |
| (0.02) | (0.37) | ($1.02) | (0.43) | (0.002) | (0.42) | ||
| Diabetes†,‡ | −0.81 | −12.44 | −0.11 | −$51.84 | −17.89 | 0.015 | 3.69 |
| (0.02) | (0.34) | ($1.18) | (0.41) | (0.002) | (0.43) | ||
| Coronary heart disease*,† | −0.81 | −12.63 | −0.11 | −$49.33 | −17.58 | 0.019 | 4.44 |
| (0.02) | (0.34) | ($1.20) | (0.43) | (0.002) | (0.42) | ||
| Cerebrovascular disease | −0.76 | −12.13 | −0.10 | −$51.98 | −18.10 | 0.019 | 4.84 |
| (0.03) | (0.50) | ($1.72) | (0.60) | (0.002) | (0.60) | ||
| COPD† | −0.91 | −14.20 | −0.12 | −$55.68 | −19.53 | 0.020 | 4.68 |
| (0.03) | (0.42) | ($1.46) | (0.51) | (0.002) | (0.53) | ||
| Arthritis | −0.74 | −12.11 | −0.10 | −$52.01 | −18.74 | 0.016 | 3.86 |
| (0.02) | (0.37) | ($1.27) | (0.46) | (0.002) | (0.46) | ||
| Sociodemographic characteristics | |||||||
| Male | −0.83 | −14.77 | −0.13 | −$52.59 | −19.82 | 0.018 | 4.43 |
| (0.03) | (0.51) | ($1.64) | (0.62) | (0.002) | (0.58) | ||
| Female | −0.84 | −14.19 | −0.12 | −$50.27 | −18.71 | 0.016 | 4.14 |
| (0.01) | (0.20) | ($0.62) | (0.23) | (0.001) | (0.24) | ||
| Race black | −0.84 | −14.55 | −0.13 | −$51.00 | −19.27 | 0.017 | 4.17 |
| (0.03) | (0.53) | ($1.65) | (0.62) | (0.002) | (0.60) | ||
| Race white | −0.84 | −14.27 | −0.12 | −$50.76 | −18.88 | 0.017 | 4.21 |
| (0.01) | (0.19) | ($0.63) | (0.23) | (0.001) | (0.24) | ||
| Other race | −0.77 | −13.55 | −0.12 | −$47.62 | −17.89 | 0.015 | 3.90 |
| (0.05) | (0.89) | ($2.72) | (1.02) | (0.004) | (1.05) | ||
| Married | −0.85 | −14.80 | −0.13 | −$51.91 | −19.59 | 0.018 | 4.55 |
| (0.02) | (0.42) | ($1.34) | (0.51) | (0.002) | (0.52) | ||
| Unmarried | −0.84 | −14.14 | −0.12 | −$50.31 | −18.70 | 0.016 | 4.09 |
| (0.01) | (0.21) | ($0.68) | (0.25) | (0.001) | (0.25) | ||
| Rural | −0.89 | −14.81 | −0.13 | −$51.31 | −19.25 | 0.017 | 4.26 |
| (0.02) | (0.30) | ($0.96) | (0.36) | (0.001) | (0.34) | ||
| Urban† | −0.81 | −13.96 | −0.12 | −$50.28 | −18.68 | 0.016 | 4.14 |
| (0.01) | (0.23) | ($0.72) | (0.27) | (0.001) | (0.28) | ||
| 64<age<75 | −0.85 | −14.51 | −0.12 | −$52.69 | −19.34 | 0.018 | 4.67 |
| (0.02) | (0.31) | ($1.04) | (0.38) | (0.002) | (0.39) | ||
| 74<age<84* | −0.83 | −14.16 | −0.12 | −$49.95 | −18.69 | 0.016 | 3.88 |
| (0.01) | (0.25) | ($0.79) | (0.30) | (0.001) | (0.30) | ||
| Age 85+* | −0.85 | −14.16 | −0.12 | −$48.48 | −18.53 | 0.017 | 4.11 |
| (0.03) | (0.48) | ($1.41) | (0.54) | (0.002) | (0.51) | ||
| 150%+FPL | −0.79 | −13.49 | −0.12 | −$47.35 | −17.61 | 0.017 | 4.39 |
| (0.02) | (0.28) | ($0.89) | (0.33) | (0.001) | (0.33) | ||
| 135–149% FPL* | −0.82 | −13.92 | −0.12 | −$51.31 | −18.96 | 0.016 | 4.09 |
| (0.03) | (0.44) | ($1.38) | (0.51) | (0.002) | (0.53) | ||
| 100–134% FPL*,† | −0.88 | −14.95 | −0.13 | −$53.07 | −20.01 | 0.015 | 3.80 |
| (0.02) | (0.34) | ($1.04) | (0.39) | (0.002) | (0.40) | ||
| Less than 100% FPL*,† | −0.94 | −15.84 | −0.14 | −$55.58 | −20.65 | 0.018 | 4.52 |
| (0.03) | (0.53) | ($1.77) | (0.66) | (0.002) | (0.59) | ||
| N | 33,397 | 33,397 | 32,722 | ||||
| R2 | 0.325 | 0.490 | — | ||||
p<.05 for tests of equivalence of marginal effects for expenditure between a given cohort and the reference cohort (denoted by italics).
p<.05 for tests of equivalence of marginal effects for utilization between a given cohort and the reference cohort.
p<.05 for tests of equivalence of marginal effects for % generic between a given cohort and the reference cohort.
Notes: Heteroskedasticity robust standard errors shown in parentheses.
All effects are significant at p<.05.
“Overall” effects are calculated at the mean of chronic disease prevalence, spending categories, and sociodemographic factors.
Effects for spending categories are calculated at the mean of rates of chronic disease prevalence and sociodemographic factors.
Effects for chronic disease categories are calculated assuming no other chronic diseases, at the mean of spending categories, and at the mean of sociodemographic factors.
Effects for sociodemographic factors are calculated at the mean of rates of chronic disease prevalence and spending categories.