Table 2.
Results of logistic regression for factors associated with switching from one generic L-thyroxine preparation to another
| Factors | OR | Lower | Upper | OR (95% CI) | p value |
|---|---|---|---|---|---|
|
| |||||
| Dose 51–100 mcg vs ≤50 mcg | 1.01 | 0.99 | 1.03 | 1.01 (0.99, 1.03) | 0.249 |
| Dose 101–200 mcg vs ≤50 mcg | 1.15 | 1.12 | 1.17 | 1.15 (1.12, 1.17) | <0.0001 |
| Dose >200 mcg vs ≤50 mcg | 1.05 | 0.84 | 1.31 | 1.05 (0.84, 1.31) | 0.6712 |
| Length of T4 before index date | 1.00 | 1.00 | 1.00 | 1.00 (1.00, 1.00) | <0.0001 |
| No. of T4 fills within 1 year: 6–10 vs 1–5 | 1.74 | 1.71 | 1.78 | 1.74 (1.71, 1.78) | <0.0001 |
| No. of T4 fills within 1 year: ≥11 vs 1–5 | 1.63 | 1.60 | 1.66 | 1.63 (1.60, 1.66) | <0.0001 |
| No. of pharmacies visited to fill L-T4: 2 vs 1 | 4.88 | 4.80 | 4.97 | 4.88 (4.80, 4.97) | <0.0001 |
| No. of pharmacies visited to fill L-T4:>2 vs 1 | 7.15 | 6.97 | 7.34 | 7.15 (6.97, 7.34) | <0.0001 |
| Age group 45–54 vs 18–44 | 1.14 | 1.10 | 1.17 | 1.14 (1.10, 1.17) | <0.0001 |
| Age group 55–64 vs 18–44 | 1.20 | 1.17 | 1.23 | 1.20 (1.17, 1.23) | <0.0001 |
| Age group 65–74 vs 18–44 | 1.26 | 1.23 | 1.30 | 1.26 (1.23, 1.30) | <0.0001 |
| Age group 75+ vs 18–44 | 1.29 | 1.26 | 1.33 | 1.29 (1.26, 1.33) | <0.0001 |
| Female vs Male | 1.02 | 1.00 | 1.04 | 1.02 (1.00, 1.04) | 0.0633 |
| Asian vs White | 1.03 | 0.99 | 1.07 | 1.03 (0.99, 1.07) | 0.1901 |
| Black vs White | 1.03 | 1.00 | 1.06 | 1.03 (1.00, 1.06) | 0.0241 |
| Hispanic vs White | 0.95 | 0.92 | 0.97 | 0.95 (0.92, 0.97) | 0.0001 |
| Unknown race vs White | 1.08 | 1.05 | 1.11 | 1.08 (1.05, 1.11) | <0.0001 |
| Northeast vs Midwest | 0.94 | 0.92 | 0.97 | 0.94 (0.92, 0.97) | <0.0001 |
| South vs Midwest | 0.92 | 0.91 | 0.94 | 0.92 (0.91, 0.94) | <0.0001 |
| West vs Midwest | 0.94 | 0.91 | 0.96 | 0.94 (0.91, 0.96) | <0.0001 |
| Provider Specialty: Other vs Endocrinology | 1.15 | 1.11 | 1.20 | 1.15 (1.11, 1.20) | <0.0001 |
| Provider Specialty: Primary Care vs Endocrinology | 1.09 | 1.06 | 1.13 | 1.09 (1.06, 1.13) | <0.0001 |
| Charlson score | 1.02 | 1.02 | 1.03 | 1.02 (1.02, 1.03) | <0.0001 |
| Atrial fibrillation(Afib) vs Non-Afib | 1.01 | 0.97 | 1.05 | 1.01 (0.97, 1.05) | 0.606 |
| Myocardial infarction(MI) vs Non-MI | 1.07 | 1.00 | 1.14 | 1.07 (1.00, 1.14) | 0.0603 |
| Congestive heart failure(CHF) vs Non-CHF | 1.05 | 1.01 | 1.09 | 1.05 (1.01, 1.09) | 0.0132 |
| Stroke vs Non-stroke | 1.05 | 0.99 | 1.11 | 1.05 (0.99, 1.11) | 0.0942 |
| Thyroid cancer vs Non-thyroid cancer | 1.01 | 0.94 | 1.08 | 1.01 (0.94, 1.08) | 0.8463 |
| Thyroid surgery vs Non-thyroid surgery | 1.22 | 1.13 | 1.31 | 1.22 (1.13, 1.31) | <0.0001 |
| Index year 2009 vs 2008 | 0.93 | 0.87 | 0.99 | 0.93 (0.87, 0.99) | 0.02 |
| Index year 2010 vs 2008 | 0.93 | 0.88 | 0.99 | 0.93 (0.88, 0.99) | 0.0275 |
| Index year 2011 vs 2008 | 1.11 | 1.05 | 1.18 | 1.11 (1.05, 1.18) | 0.0006 |
| Index year 2012 vs 2008 | 1.13 | 1.06 | 1.20 | 1.13 (1.06, 1.20) | <0.0001 |
| Index year 2013 vs 2008 | 1.65 | 1.56 | 1.74 | 1.65 (1.56, 1.74) | <0.0001 |
| Index year 2014 vs 2008 | 2.62 | 2.48 | 2.77 | 2.62 (2.48, 2.77) | <0.0001 |
| Index year 2015 vs 2008 | 1.42 | 1.34 | 1.50 | 1.42 (1.34, 1.50) | <0.0001 |
| Index year 2016 vs 2008 | 1.62 | 1.54 | 1.71 | 1.62 (1.54, 1.71) | <0.0001 |
| Index year 2017 vs 2008 | 2.22 | 2.10 | 2.34 | 2.22 (2.10, 2.34) | <0.0001 |
| Index year 2018 vs 2008 | 3.32 | 3.14 | 3.51 | 3.32 (3.14, 3.51) | <0.0001 |