TABLE 2.
Smoking and pack‐years and the risk of recurrent CRN based on univariable and adjusted PWP‐total time Cox proportional hazards models.
| Total cohort (n = 501 of whom 105 ≥1 CRN event) | UC or IBD‐U (n = 277 of whom 66 ≥1 CRN event) | CD (n = 224 of whom 39 ≥1 CRN event) | ||||
|---|---|---|---|---|---|---|
| HR (95% CI) | p | HR (95% CI) | p | HR (95% CI) | p | |
| Univariable analyses | ||||||
| Ever smoking (reference = never) | 1.19 (0.88–1.61) | 0.27 | 1.27 (0.84–1.93) | 0.26 | 1.17 (0.69–1.98) | 0.57 |
| Pack‐years (per 10 pack‐year increase) | 1.24 (1.10–1.40) | <0.05 | 1.22 (1.04–1.42) | <0.05 | 1.18 (0.95–1.48) | 0.14 |
| Adjusted analyses a | ||||||
| Ever smoking (reference = never) | 1.04 (0.75–1.44) | 0.82 | 1.03 (0.64–1.64) | 0.91 | 0.91 (0.49–1.66) | 0.74 |
| Pack‐years (per 10 pack‐year increase) | 1.17 (1.03–1.32) | <0.05 | 1.08 (0.91–1.28) | 0.36 | 1.08 (0.86–1.37) | 0.49 |
Note: p‐values of interaction terms between IBD type and smoking status or pack‐years are, respectively, 0.89 and 0.86 (Wald test).
Abbreviations: CD, Crohn's disease; CI, confidence interval; CRN, colorectal neoplasia; HR, hazard ratio; IBD‐U, inflammatory bowel disease‐unclassified; n, number; PWP, Prentice, Williams, and Peterson; UC, ulcerative colitis.
HR adjusted for extensive disease, first‐degree relative with colorectal cancer, primary sclerosing cholangitis, male sex, age (per year increase, restricted cubic spline with four knots), prior or index colorectal neoplasia, and mean endoscopic inflammation (scale 0–3, included as time‐varying covariate).