The Cochrane review on nicotine replacement therapy: incorrect or uncertain classifications of additional support levels
- Correspondence to: Dr R A Walsh Centre for Health Research & Psycho-oncology, Cancer Council NSW/University of Newcastle/Hunter Medical Research Institute, Locked Mail Bag 10, Wallsend, NSW 2287, Australia;
The Cochrane review of nicotine replacement therapy (NRT) has concluded that the effectiveness of NRT seems to be largely independent of the intensity of additional support provided to the smoker.1 In fact, trends in their data indicate that NRT had a relatively greater effect (higher odds ratios favouring treatment) when given with minimal support, even though the absolute increase in abstinence rates was larger when combined with high-intensity support.
In the Cochrane review,1 low-intensity additional support was regarded as part of the provision of routine care. If the duration of time spent with the smoker (including assessment for the trial) exceeded 30 min at the initial consultation or the number of further assessment and reinforcement visits exceeded two, the level of additional support was categorised as high. Categorisations were based predominantly on published reports.
While examining NRT trials involving community volunteers for another project, I noted apparent anomalies in support level classifications of the Cochrane review.1 A systematic examination of adjunctive treatment of the 14 English language, community volunteer smoking cessation trials listed in the Cochrane review, which included a placebo or no NRT condition and which were categorised as low support was then undertaken.
In 6 (43%) trials, published descriptions supported the Cochrane review classification as low-level support and 3 (21%) trials2–4 did clearly not appear to satisfy the Cochrane review criteria. In 5 (36%) trials,5–9 lack of a Cochrane definition concerning what constitutes …