Do implementation issues influence the effectiveness of medications? The case of nicotine replacement therapy and bupropion in UK Stop Smoking Services

BMC Public Health Do implementation issues influence the effectiveness of medications? The case of nicotine replacement therapy and bupropion in UK Stop Smoking Services Andy McEwen* and Robert West 0 Address: Cancer Research UK Health Behaviour Research Centre, University College London , London, WC1E 6BT , UK Background: Effective pharmacotherapies are available for smoking cessation but their efficacy is established through randomised controlled trials where the medication is supplied direct to subjects. In health care settings patient access to medicines is often less direct. The process for obtaining supplies of nicotine replacement therapy (NRT) is relatively easy for smokers attending National Health Service (NHS) Stop Smoking Services in the UK, whilst this is not necessarily the case for those wishing to using prescription only medicines (e.g. bupropion and varenicline). This study was a direct comparison of the short-term validated abstinence rates of NRT and bupropion in a clinical setting. Methods: Data were routinely collected from 2626 clients setting a quit date (82% of those registering) with two London NHS Stop Smoking Services that offered behavioural support combined with pharmacotherapy (NRT and bupropion). Results: Contrary to what would be expected from multiple randomised controlled trials, the CO-validated 3-4 week abstinence rate in clients using NRT was higher than for bupropion (42% versus 34%, p = .003). This difference persisted even when controlling for smoking characteristics, demographic variables and treatment variables 1.40 (95% CI = 1.08 - 1.83). Conclusion: Given that the level of behavioural support received by clients on each medication was identical, the most plausible explanation for the difference in effectiveness between NRT and bupropion perhaps lies with how clients of the Stop Smoking Services obtained their medications. Obtaining NRT was relatively easy for clients throughout the study period whilst this was not the case for bupropion. This study suggests that implementation issues and/or self-selection may influence the effectiveness of medications in health care, as opposed to research, settings. - Background The efficacy of pharmacotherapies is established through randomised controlled trials where the medication is supplied direct to subjects. In health care settings patient access to medicines is often less direct and this may influence compliance with, and effectiveness of, medications. Both nicotine replacement therapy (NRT) and bupropion (Zyban) are of proven efficacy in helping smokers to quit. The most recent Cochrane review of multiple randomised controlled trials of NRT found that the overall odds ratio for long-term (6-month) abstinence with NRT, irrespective of additional support, compared to placebo was 1.77 (95% confidence intervals: 1.66 1.88) [1]. A Cochrane review of over thirty trials of bupropion established that the odds ratio for achieving abstinence from smoking for at least six months was 1.94 (95% confidence interval: 1.72 to 2.19) [2]. Analysis of the three head-to-head trials of bupropion and NRT included in the second of these reviews also revealed that bupropion is slightly more effective in helping smokers to achieve long term abstinence from smoking: the overall odds ratio was 1.34 (95% confidence interval: 0.71 to 2.56) [3-5]. A UK Government white paper in 1998 established the importance of the treatment of tobacco dependence and laid out a strategy for a NHS (National Health Service) Stop Smoking Service [6]. Funding to create and develop these stop smoking services was made available to all areas by 2000 and by the end of 2001 most were fully operational [7]. Bupropion became available on NHS prescription in June 2000; a supply of four to six weeks of NRT was obtainable via a voucher scheme operated by NHS Stop Smoking Services up until April 2001 when it too became available as an NHS reimbursable drug treatment for smoking cessation [8]. This paper details previously unreported prior medication use of clients attending NHS Stop Smoking Services and what medication clients' chose to use to aid their quit attempt. Our data allows us to report on usage of different NRT products, and of bupropion, and to consider the effectiveness of these medications in assisting clients achieve short term abstinence in a clinical as opposed to research setting. The data also allows for a direct comparison to be made between the effectiveness of these medications as the level of behavioural support received by clients on each medication type is identical. There is evidence that providing free NRT to smokers can induce a large number to make a quit attempt [9]; and that making obtaining NRT easier (by switching the medication from prescription only to over the counter [OTC]) can result in increased use of NRT [10]. However, these large population-based cohort studies do not reflect what goes on in clinical practice and to our knowledge there are no studies that have considered how different routes of access to smoking cessation medications can influence their effectiveness. Methods The research took place at two NHS Stop Smoking Services covering, in total, five outer London boroughs (Merton, Sutton & Wandsworth; Redbridge and Waltham Forest) with a combined population of about one million. These boroughs represent a diverse mix of inner city and suburban residential areas where the percentage of people of working age claiming key social benefits is 10% (Merton, Sutton & Wandsworth), 14% (Redbridge) and 18% (Waltham Forest); the average for London is 15% [11]. In both of these distinct services, the treatment regimen comprised six weekly 12 hour clinic (group) or community (one-to-one) support sessions over five or six weeks. This 'withdrawal-oriented treatment' [12] is recommended in smoking cessation guidelines [13] and combines behavioural support and pharmacotherapy (NRT or bupropion). This regimen is described in more detail elsewhere [14] but basically involves a pre-quit session to inform clients of what treatment involves, including deciding upon what medication they are going to use to aid their quit attempt. Subsequent sessions inform clients about the nature of the tobacco withdrawal syndrome and provide advice on how to manage the symptoms, ensure that clients have a sufficient supply of medication and are using it properly and provide encouragement designed to bolster motivation to remain abstinent. All NHS stop smoking services collect demographic data on clients plus abstinence data for four weeks post-quit. The services reported in this paper also routinely collected additional data including: past quit attempts, prior medication use, indicated cautions and contraindications, choice of medication, side effects of medication use and dependence on smoking Fagerstrm test for nicotine dependence (FTND) [15]. Data were collected as part of routine clinical practice and all clients ga (...truncated)