Table 2.
Direct and Indirect Effects of Exposure (to FGAs vs. SGAs) on Mortality Risk, Mediated by Stroke, Over 180 Days of Follow-up Among Adults Aged 65 Years or Older With Dual Enrollment in Medicare and Pharmacy Assistance Programs in New Jersey or Pennsylvania, 1994–2005
| Analysis | Controlled Direct Effect |
Natural Direct Effect |
Natural Indirect Effect |
Total Effect |
Proportion Mediated, % |
||||
|---|---|---|---|---|---|---|---|---|---|
| RR | 95% CI | RR | 95% CI | RR | 95% CI | RR | 95% CI | ||
| Unadjusteda | 1.13 | 1.08, 1.21 | 1.13 | 1.07, 1.20 | 1.004 | 0.999, 1.009 | 1.13 | 1.07, 1.20 | 3.27 |
| Multivariable adjustedb |
|||||||||
| Days since initiation | |||||||||
| 14 | 1.43 | 1.11, 1.81 | 1.42 | 1.10, 1.80 | 1.000 | 1.000, 1.000 | 1.42 | 1.10, 1.80 | −0.01 |
| 30 | 1.25 | 1.06, 1.47 | 1.25 | 1.06, 1.47 | 1.001 | 1.000, 1.003 | 1.25 | 1.07, 1.47 | 0.38 |
| 60 | 1.22 | 1.09, 1.36 | 1.22 | 1.10, 1.36 | 1.005 | 1.001, 1.012c | 1.23 | 1.11, 1.36 | 2.73 |
| 120 | 1.21 | 1.12, 1.31 | 1.21 | 1.12, 1.30 | 1.004 | 1.001, 1.012c | 1.21 | 1.13, 1.31 | 2.34 |
| 180 | 1.15 | 1.08, 1.22 | 1.15 | 1.08, 1.22 | 1.004 | 1.000, 1.008c | 1.15 | 1.08, 1.22 | 2.70 |
| Stroke subtypea | |||||||||
| Ischemic | 1.15 | 1.08, 1.22 | 1.17 | 1.08, 1.22 | 1.003 | 1.000, 1.006 | 1.15 | 1.08, 1.22 | 2.02 |
| Hemorrhagic | 1.15 | 1.08, 1.22 | 1.15 | 1.08, 1.22 | 1.000 | 0.999, 1.002 | 1.15 | 1.08, 1.22 | 0.22 |
Abbreviations: CI, confidence interval; FGA, first-generation antipsychotic drug; RR, risk ratio; SGA, second-generation antipsychotic drug.
a All analyses were conducted over 180 days since initiation unless noted otherwise.
b Multivariable analyses adjusted for demographic characteristics, health services usage, comorbid chronic and psychiatric conditions, and concomitant medication use occurring before the index date, as listed in Web Table 1.
c The lower confidence bound for indirect effect is above the null.