Duration of exposure (months) | HR (95% CI; p value) Unadjusted Cox Model | Adjusted Cox Model HRa (95% CI; p value) | Marginal Structural Model HRb (95% CI; p value) |
---|---|---|---|
Never exposed | Referent | Referent | Referent |
1–6 | 1.66 (1.23, 2.25; p = 0.001) | 1.24 (0.92, 1.67; p = 0.163) | 1.25 (0.92, 1.70; p = 0.150) |
7–12 | 1.69 (1.15, 2.47; p = 0.007) | 1.27 (0.87, 1.86; p = 0.219) | 1.41 (0.97, 2.06; p = 0.073) |
13–18 | 2.28 (1.48, 3.54; p < 0.001) | 1.71 (1.10, 2.65; p = 0.016) | 1.78 (1.16, 2.72; p = 0.009) |
19–24 | 2.09 (1.26, 3.47; p = 0.004) | 1.62 (0.98, 2.69; p = 0.060) | 1.90 (1.16, 3.11; p = 0.011) |
>25 | 1.45 (0.97, 2.18; p = 0.071) | 1.20 (0.80, 1.80; p = 0.386) | 1.30 (0.86, 1.97; p = 0.208) |