Near patient tests for smoking cessation
http://www.100md.com
《英国医生杂志》
Needs to be compared with other interventions
Near patient testing (at the point of care) is a term used to describe investigations done in clinical settings that yield results available immediately without the need for a laboratory.1 Until now, near patient testing has been used mainly for diagnosis, such as for urine analysis, and for monitoring conditions such as diabetes or response to treatments such as warfarin.1 In addition, measurements of carbon monoxide in expired air are used to monitor smoking cessation, but this has not been evaluated fully. In this week's BMJ Barnfather and colleagues report the results of a randomised controlled trial in which a near patient test for nicotine metabolites in saliva was used to encourage smoking cessation by dental patients.2
For each trial participant, the saliva test produced a single numerical result relating to the salivary cotinine concentration and showing how heavily the person smoked. In all, 100 smokers took the saliva test and were then randomised either to receive the test results with interpretation and feedback or not to receive the results at all. Eight weeks after testing, 23% of the intervention group had stopped smoking compared with only 7% of controls. All participants' self reported levels of smoking were validated biochemically using the new saliva test. Although these preliminary results seem impressive, they should be considered alongside what is already known about interventions for smoking cessation in primary care.
Dentists, in common with general practitioners,3 can stimulate patients to stop smoking simply by advising them to stop.4 Although the size of this effect has been small (but significant) in studies, health professionals can make a considerable impact on public health by incorporating such advice into their routine care.4 The new study by Barnfather and colleagues cannot tell us, however, whether the new test for nicotine metabolites is any more or less effective for smoking cessation than dentists' advice. All trial participants were advised against smoking by their dentist, and all were administered the test; the only comparison was disclosure and feedback of test results versus non-disclosure.2 Determining whether or not testing is indeed any more or less effective than dentists' advice would be possible only with the inclusion of a trial arm in which patients received the advice alone (with no testing). Before dental practitioners, primary care trusts, and NHS Stop Smoking services adopt near patient testing for nicotine metabolites, we need cluster randomised trials that can distinguish the effects of brief advice from those attributable to near patient testing.5
Secondly, such trials should investigate longer term outcomes. Barnfather and colleagues measured smoking cessation at eight weeks,2 but many people who stop smoking for two months or more will start again.6 Follow-up over six or even 12 months has been suggested as the primary outcome for smoking cessation studies.7 In this week's paper the reported rates of smoking cessation attributable to test disclosure only just reached statistical significance at eight weeks. Because relapse to smoking increases with time since quitting,6 it is unlikely that cessation rates would still be significantly better in the intervention group at six or 12 months after randomisation.
Furthermore, if trials do show longer term effectiveness of the new test for cessation, we should try to identify which smokers are most likely to benefit. The smokers recruited by Barnfather and colleagues were not required to state a desire to stop smoking, but all had to consent to two extra visits to their dental practitioner for counselling on smoking cessation.2 The participants therefore probably all had some degree of motivation to stop smoking. Consequently, the findings of this trial imply that disclosure of test results could assist smoking cessation in motivated dental patients seen outside routine dental care. We would need evidence that this intervention is effective for unselected patients before introducing it as a routine component of all dental patients' care.
More fundamentally, we should ask whether other near patient tests like that for carbon monoxide in expired air might have similar effects to those of the new test for nicotine metabolites in saliva. Measuring carbon monoxide in expired air also provides numerical readings that can reflect how much the person tested smokes,8 presenting smokers with an immediate impression of the harm that their smoking is doing them. Carbon monoxide from exposure to environmental tobacco smoke is detectable in non-smokers' expired air, but usually at levels below 10 parts per million, so readings from expired air differentiate passive exposure from smoking.8 All English NHS Stop Smoking services already use expired carbon monoxide readings to verify clients' reports of smoking cessation,9 and some give feedback to influence or encourage quitting.
Trials conducted more than 20 years ago first investigated the impact on quit rates of estimations of carbon monoxide in expired air.10 There is, however, still insufficient evidence to say whether this feedback method has any additional impact when delivered with doctors' brief advice against smoking.3 A systematic review is now in hand, synthesising data on whether assessments of biomedical risk (including carbon monoxide in expired air) are effective for smoking cessation.11 This review should now also include these new data on near patient tests for salivary nicotine metabolites.
Lastly, future evaluations of near patient tests for smoking cessation should also include direct cost effectiveness comparisons between tests that are of proved effectiveness.
Tim Coleman, senior lecturer in general practice
Division of Primary Care, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH (tim.coleman@nottingham.ac.uk)
Primary care p 999
Competing interests: TC has been paid for speaking by GlaxoSmithKline (once) and for consultancy work for Pharmacia. Both companies produce nicotine replacement treatments.
References
Delaney BC, Hyde CJ, McManus RJ, Wilson S, Fitzmaurice DA, Jowett S, et al. Systematic review of near patient test evaluations in primary care. BMJ 1999;319: 824-7.
Barnfather KD, Cope GF, Chapple IL. Effect of incorporating a 10 minute point of care test for salivary nicotine metabolites into a general practice based smoking cessation programme: randomised controlled trial. BMJ 2005;331: 999-1001.
Lancaster T, Stead LF. Physician advice for smoking cessation. Cochrane Database Syst Rev 2004;(4): CD000165.
Gorin SS, Heck JE. Meta-analysis of the efficacy of tobacco counselling by health care providers. Cancer Epidemiol Biomarkers Prev 2004;13: 2012-22.
Ukoumunne OC, Gulliford MC, Chinn S, Sterne JAC, Burney PGJ. Methods for evaluating area-wide and organisation-based interventions in health and health care: a systematic review. Health Technol Assess 1999;3(5): iii-92.
Stapleton J. Cigarette smoking prevalence, cessation and relapse. Stat Methods Med Res 1998;7: 187-203.
Hughes JR, Keely JP, Niaura RS, Ossip-Klein DJ, Richmond RL, Swan GE. Measures of abstinence in clinical trials: issues and recommendations. Nicotine Tob Res 2003;5: 13-25.
SRNT Subcommittee on Biochemical Verification. Biochemical verification of tobacco use and cessation. Nicotine Tob Res 2002;4: 149-59.
McNeill A, Raw M, Whybrow J, Bailey P. A national strategy for smoking cessation treatment in England. Addiction 2005;100(suppl 2): 1-11.
Jamrozik K, Vessey M, Fowler G, Wald N, Parker G, Van Vunakis H. Controlled trial of three different antismoking interventions in general practice. BMJ 1984;288: 1499-503.
Bize R, Burnand B, Cornuz J. Biomedical risk assessment as an aid for smoking cessation. Cochrane Database Syst Rev: Protocols 2004;(2): CD004705. (doi: 10.1002/14651858.CD004705.)
Near patient testing (at the point of care) is a term used to describe investigations done in clinical settings that yield results available immediately without the need for a laboratory.1 Until now, near patient testing has been used mainly for diagnosis, such as for urine analysis, and for monitoring conditions such as diabetes or response to treatments such as warfarin.1 In addition, measurements of carbon monoxide in expired air are used to monitor smoking cessation, but this has not been evaluated fully. In this week's BMJ Barnfather and colleagues report the results of a randomised controlled trial in which a near patient test for nicotine metabolites in saliva was used to encourage smoking cessation by dental patients.2
For each trial participant, the saliva test produced a single numerical result relating to the salivary cotinine concentration and showing how heavily the person smoked. In all, 100 smokers took the saliva test and were then randomised either to receive the test results with interpretation and feedback or not to receive the results at all. Eight weeks after testing, 23% of the intervention group had stopped smoking compared with only 7% of controls. All participants' self reported levels of smoking were validated biochemically using the new saliva test. Although these preliminary results seem impressive, they should be considered alongside what is already known about interventions for smoking cessation in primary care.
Dentists, in common with general practitioners,3 can stimulate patients to stop smoking simply by advising them to stop.4 Although the size of this effect has been small (but significant) in studies, health professionals can make a considerable impact on public health by incorporating such advice into their routine care.4 The new study by Barnfather and colleagues cannot tell us, however, whether the new test for nicotine metabolites is any more or less effective for smoking cessation than dentists' advice. All trial participants were advised against smoking by their dentist, and all were administered the test; the only comparison was disclosure and feedback of test results versus non-disclosure.2 Determining whether or not testing is indeed any more or less effective than dentists' advice would be possible only with the inclusion of a trial arm in which patients received the advice alone (with no testing). Before dental practitioners, primary care trusts, and NHS Stop Smoking services adopt near patient testing for nicotine metabolites, we need cluster randomised trials that can distinguish the effects of brief advice from those attributable to near patient testing.5
Secondly, such trials should investigate longer term outcomes. Barnfather and colleagues measured smoking cessation at eight weeks,2 but many people who stop smoking for two months or more will start again.6 Follow-up over six or even 12 months has been suggested as the primary outcome for smoking cessation studies.7 In this week's paper the reported rates of smoking cessation attributable to test disclosure only just reached statistical significance at eight weeks. Because relapse to smoking increases with time since quitting,6 it is unlikely that cessation rates would still be significantly better in the intervention group at six or 12 months after randomisation.
Furthermore, if trials do show longer term effectiveness of the new test for cessation, we should try to identify which smokers are most likely to benefit. The smokers recruited by Barnfather and colleagues were not required to state a desire to stop smoking, but all had to consent to two extra visits to their dental practitioner for counselling on smoking cessation.2 The participants therefore probably all had some degree of motivation to stop smoking. Consequently, the findings of this trial imply that disclosure of test results could assist smoking cessation in motivated dental patients seen outside routine dental care. We would need evidence that this intervention is effective for unselected patients before introducing it as a routine component of all dental patients' care.
More fundamentally, we should ask whether other near patient tests like that for carbon monoxide in expired air might have similar effects to those of the new test for nicotine metabolites in saliva. Measuring carbon monoxide in expired air also provides numerical readings that can reflect how much the person tested smokes,8 presenting smokers with an immediate impression of the harm that their smoking is doing them. Carbon monoxide from exposure to environmental tobacco smoke is detectable in non-smokers' expired air, but usually at levels below 10 parts per million, so readings from expired air differentiate passive exposure from smoking.8 All English NHS Stop Smoking services already use expired carbon monoxide readings to verify clients' reports of smoking cessation,9 and some give feedback to influence or encourage quitting.
Trials conducted more than 20 years ago first investigated the impact on quit rates of estimations of carbon monoxide in expired air.10 There is, however, still insufficient evidence to say whether this feedback method has any additional impact when delivered with doctors' brief advice against smoking.3 A systematic review is now in hand, synthesising data on whether assessments of biomedical risk (including carbon monoxide in expired air) are effective for smoking cessation.11 This review should now also include these new data on near patient tests for salivary nicotine metabolites.
Lastly, future evaluations of near patient tests for smoking cessation should also include direct cost effectiveness comparisons between tests that are of proved effectiveness.
Tim Coleman, senior lecturer in general practice
Division of Primary Care, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH (tim.coleman@nottingham.ac.uk)
Primary care p 999
Competing interests: TC has been paid for speaking by GlaxoSmithKline (once) and for consultancy work for Pharmacia. Both companies produce nicotine replacement treatments.
References
Delaney BC, Hyde CJ, McManus RJ, Wilson S, Fitzmaurice DA, Jowett S, et al. Systematic review of near patient test evaluations in primary care. BMJ 1999;319: 824-7.
Barnfather KD, Cope GF, Chapple IL. Effect of incorporating a 10 minute point of care test for salivary nicotine metabolites into a general practice based smoking cessation programme: randomised controlled trial. BMJ 2005;331: 999-1001.
Lancaster T, Stead LF. Physician advice for smoking cessation. Cochrane Database Syst Rev 2004;(4): CD000165.
Gorin SS, Heck JE. Meta-analysis of the efficacy of tobacco counselling by health care providers. Cancer Epidemiol Biomarkers Prev 2004;13: 2012-22.
Ukoumunne OC, Gulliford MC, Chinn S, Sterne JAC, Burney PGJ. Methods for evaluating area-wide and organisation-based interventions in health and health care: a systematic review. Health Technol Assess 1999;3(5): iii-92.
Stapleton J. Cigarette smoking prevalence, cessation and relapse. Stat Methods Med Res 1998;7: 187-203.
Hughes JR, Keely JP, Niaura RS, Ossip-Klein DJ, Richmond RL, Swan GE. Measures of abstinence in clinical trials: issues and recommendations. Nicotine Tob Res 2003;5: 13-25.
SRNT Subcommittee on Biochemical Verification. Biochemical verification of tobacco use and cessation. Nicotine Tob Res 2002;4: 149-59.
McNeill A, Raw M, Whybrow J, Bailey P. A national strategy for smoking cessation treatment in England. Addiction 2005;100(suppl 2): 1-11.
Jamrozik K, Vessey M, Fowler G, Wald N, Parker G, Van Vunakis H. Controlled trial of three different antismoking interventions in general practice. BMJ 1984;288: 1499-503.
Bize R, Burnand B, Cornuz J. Biomedical risk assessment as an aid for smoking cessation. Cochrane Database Syst Rev: Protocols 2004;(2): CD004705. (doi: 10.1002/14651858.CD004705.)