Table 2.
Risk of treatment emergent, cardiovascular serious adverse events associated with varenicline use in double blind, placebo controlled randomised trials of tobacco cessation
| Study | Events/randomised participants (no) | Allocation ratio between study groups | Treatment effect (95% confidence interval) | ||||
|---|---|---|---|---|---|---|---|
| Varenicline | Placebo | Peto odds ratio | Odds ratio | Relative risk | Risk difference (%) | ||
| Fagerstrom et al24 | 0/214 | 1/218 | 1:1 | 0.14 (0.00 to 6.95) | 0.34 (0.14 to 8.34) | 0.34 (0.01 to 8.29) | −0.46 (−1.73 to 0.81) |
| Rennard et al44 | 0/493 | 0/166 | 3:1 | UC | UC | UC | 0 (−0.87 to 0.87) |
| Protocol A305107240 | 0/85 | 0/43 | 2:1 | UC | UC | UC | 0 (−3.52 to 3.52) |
| Hong et al26 | 0/20 | 0/21 | 1:1 | UC | UC | UC | 0 (−9.00 to 9.00) |
| Ebbert et al34 | 0/38 | 0/38 | 1:1 | UC | UC | UC | 0 (−4.99 to 4.99) |
| Garza et al41 | 0/55 | 0/55 | 1:1 | UC | UC | UC | 0 (−3.48 to 3.48) |
| Hughes et al48 | 0/107 | 0/111 | 1:1 | UC | UC | UC | 0 (−1.78 to 1.78) |
| Wang et al46 | 0/165 | 0/168 | 1:1 | UC | UC | UC | 0 (−1.17 to 1.17) |
| Poling et al52 | 0/13 | 0/18 | 0.7:1 | UC | UC | UC | 0 (−12.10 to 12.10) |
| Steinberg et al25 | 1/40 | 1/39 | 1:1 | 0.98 (0.06 to 15.87) | 0.97 (0.06 to 16.15) | 0.98 (0.06 to 15.05) | −0.06 (−0.07 to 6.87) |
| Jorenby et al43 | 1/344 | 1/341 | 1:1 | 0.99 (0.06 to 15.88) | 0.99 (0.06 to 15.91) | 0.99 (0.06 to 15.78) | 0.00 (−0.81 to 0.81) |
| Gonzales et al42 | 2/352 | 2/344 | 1:1 | 0.98 (0.14 to 6.97) | 0.98 (0.14 to 6.98) | 0.98 (0.14 to 6.90) | −0.01 (−1.14 to 1.11) |
| Rigotti et al11 | 10/355 | 10/359 | 1:1 | 1.01 (0.42 to 2.46) | 1.01 (0.42 to 2.46) | 1.01 (0.43 to 2.40) | 0.03 (−2.39 to 2.45) |
| Oncken et al51 | 2/518 | 0/129 | 4:1 | 3.49 (0.11 to 112.44) | 1.25 (0.06 to 26.27) | 1.25 (0.06 to 25.93) | 0.39 (−0.83 to 1.61) |
| Nides et al50 | 1/383 | 0/127 | 3:1 | 3.79 (0.04 to 352.09) | 1.00 (0.04 to 24.70) | 1.00 (0.04 to 24.39) | 0.26 (−0.99 to 1.51) |
| Nakamura et al20 | 1/465 | 0/154 | 3:1 | 3.79 (0.04 to 352.44) | 1.00 (0.04 to 24.62) | 1.00 (0.04 to 24.37) | 0.22 (−0.82 to 1.25) |
| Bolliger et al37 | 1/394 | 0/199 | 2:1 | 4.50 (0.07 to 285.96) | 1.52 (0.06 to 37.51) | 1.52 (0.06 to 37.12) | 0.25 (−0.67 to 1.17) |
| Tsai et al53 | 1/126 | 0/124 | 1:1 | 7.27 (0.14 to 366.57) | 2.98 (0.12 to 73.76) | 2.95 (0.12 to 71.79) | 0.79 (−1.39 to 2.97) |
| Niaura et al49 | 2/160 | 0/160 | 1:1 | 7.44 (0.46 to 119.40) | 5.06 (0.24 to 106.30) | 5.00 (0.24 to 103.33) | 1.25 (−0.84 to 3.34) |
| Tonstad et al36 | 2/603 | 0/607 | 1:1 | 7.45 (0.47 to 119.26) | 5.05 (0.24 to 105.41) | 5.03 (0.24 to 104.62) | 0.33 (−0.23 to 0.89) |
| Williams et al47 | 6/251 | 1/126 | 2:1 | 2.40 (0.49 to 11.67) | 3.06 (0.37 to 25.71) | 3.01 (0.37 to 24.75) | 1.60 (−0.85 to 4.04) |
| Tashkin et al45 | 4/250 | 2/254 | 1:1 | 1.99 (0.40 to 9.95) | 2.05 (0.37 to 11.29) | 2.03 (0.38 to 10.99) | 0.81 (−1.08 to 2.71) |
| All trials combined | 34/5431 | 18/3801 | — | 1.58 (0.90 to 2.76) | 1.41 (0.82 to 2.42) | 1.40 (0.82 to 2.39) | 0.27 (−0.10 to 0.63) |
Studies grouped by presence (v absence) of events and equal (v unequal) numbers of events; groups ordered by increasing evidence of a varenicline effect. UC=unable to calculate using Peto odds ratio, Mantel-Haenszel odds ratio, and relative risk because no events in either group.