Walker 2014
| Methods | Country: New Zealand Setting: National Quitline Aim: "a non‐inferiority trial to investigate whether cytisine was at least as effective as nicotine‐replacement‐therapy" Study Design: parallel‐group non‐inferiority RCT Dates conducted: March 2011 ‐ February 2013 Analysis: Power calculation (90%, 1‐tailed, alpha = 0.05) and assuming a 20% loss to follow‐up, to detect a 5% difference in 1‐month quit rates; cytisine 1‐month quit rate was assumed to be 55%, with a non‐inferiority margin of 5% |
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| Participants | 1310 daily smokers, callers to the NZ National Quitline, aged 18+, motivated to quit. Allocated to cytisine (655) or to open‐label NRT (655). Mean age 38, 57% women, 33% NZ Maori, mean CPD 19, mean FTND 5.4 | |
| Interventions | All participants received standard Quitline support, i.e. average 3 x 10 ‐ 15‐minute calls over 8 wks 1. 25‐day course of cytisine (Tabex) tablets, + NRT vouchers in case they needed them AFTER completing the cytisine course 2. Usual care, i.e. 8‐week course of NRT (patch, gum or lozenge), tailored to dependence level, supplied by vouchers |
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| Outcomes | Self‐reported CAR (5 cigarettes or fewer) at 1m CAR and 7‐day PPA (no smoking) at 1 wk, 1m, 2m and 6m. Adverse events Validation: None used |
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| Treatment type | Medication: CYTISINE [TABEX] / NRT OPEN‐LABEL | |
| Notes | Funding by Health Research Council of New Zealand; cytisine supplied at no cost by Sopharma New for 2016 update |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "randomly allocated, by computer ... in a 1:1 ratio" |
| Allocation concealment (selection bias) | Low risk | "Randomization was stratified with the use of minimization according to sex, ethnicity (Maori, Pacific Islander, or non‐Maori and non–Pacific Islander), and cigarette dependence, which was determined by means of the Fagerström Test of Cigarette Dependence, in which smokers were assigned to one of two groups: those with scores of 5 or lower, indicating lower dependence, and those with scores greater than 5, indicating greater dependence" |
| Blinding (performance bias and detection bias) All outcomes | High risk | "Participants and researchers collecting outcome data were aware of treatment allocation" |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Losses fully reported. By 6m, 182 cytisine participants (28%) lost to follow‐up, and 16 withdrawals; 173 NRT participants (26%) lost to follow‐up, and 14 withdrawals. 19 cytisine users crossed over to NRT, and 1 NRT user crossed over to cytisine. ITT analyses conducted |
| Selective reporting (reporting bias) | Low risk | None noted |
| Other bias | Unclear risk | Cytisine was supplied free, while NRT users had to pay a nominal charge (NZD 3 for an 8‐wk course of each NRT item); Duration of treatment differed (25 days vs 8 wks), but 1º outcome set to 1m to counteract this |