The European Journal of Public Health Advance Access originally published online on May 19, 2005
The European Journal of Public Health 2005 15(3):251-255; doi:10.1093/eurpub/cki076
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Smoking |
Nicotine dependence treatment: perceived health status improvement with 1-year continuous smoking abstinence
Ivana T. Croghan1, Darrell R. Schroeder2, J. Taylor Hays3, Kay M. Eberman4, Christi A. Patten1,5, Emily J. Berg1 and Richard D. Hurt1,6
1 Nicotine Research Program
2 Department of Health Sciences Research
3 Division of General Internal Medicine
4 Nicotine Dependence Center
5 Department of Psychiatry and Psychology
6 Division of Community Internal Medicine, Mayo Clinic and Mayo Foundation, Rochester, MN, USA
Correspondence: Ivana T. Croghan, PhD, Mayo Clinic, 200 First Street S.W., Rochester, MN 55905, USA, tel. +1 507 266 1944, fax +1 507 266 7900, Email: croghan.ivana{at}mayo.edu
Received March 19, 2003, accepted November 10, 2003
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Abstract |
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Background: This study evaluated change in health status as a function of change in smoking status among patients treated clinically for nicotine dependence by comparing overall perceived health status of patients who abstained from cigarettes for 1 year versus those who smoked continuously for 1 year. Methods: Patients from the Mayo Clinic Nicotine Dependence Center completed a quality-of-life questionnaire (SF-36) following their consultation for nicotine dependence (baseline). At 1 year post-intervention, patients were mailed a follow-up survey that included the SF-36 and items assessing interval smoking history. Study patients included those who self-reported continuous smoking (n=60) and those reporting continuous smoking abstinence for the entire follow-up year (n=146). Data from SF-36 scales at 1 year were analysed using analysis of covariance with baseline scale scores serving as covariates along with baseline characteristics that differed significantly between groups. Results: Compared with those who continued to smoke, patients who were continuously abstinent from smoking for the entire year had more improvement in perceived health status for the SF-36 mental composite scale (P=0.009) and for the SF-36 subscales for role limitations (P<0.001 and P=0.017 for emotional and physical role limitations, respectively), social functioning (P=0.010) and general health (P=0.013). Conclusions: Smokers treated for nicotine dependence who stop smoking for a year report more improvement in-quality-of-life compared with those who continue to smoke.
Keywords: nicotine dependence, quality-of-life, SF-36, smoking, treatment
The benefits of smoking cessation are substantial, ranging from improvement of respiratory symptoms to an increase in years of life.1–4 In a prior study, it was found that smoking cessation using clinical services at the Mayo Clinic Nicotine Dependence Center is cost-effective.4 Although it was concluded that stopping smoking may increase life span, little is known about the health-related quality-of-life following treatment for nicotine dependence.
The SF-36 is a generic health questionnaire, designed as a part of the Health Insurance Experiment and Medical Outcome Study, to assess health-related quality-of-life outcomes most directly affected by disease and treatment.5 When compared with other health-related quality-of-life measures, the SF-36 has been found to discriminate better among individuals with varying levels of self-reported general health status and co-morbidity.6,7 The Health Status Questionnaire (HSQ), which was used in this study, is a 39-item instrument that contains the SF-36 items and three additional items used to screen for depression.8
There is currently very little information about potential changes in health-related quality-of-life that can be provided to smokers who are trying to quit. One study found that, dependent on the amount of time since abstinence was achieved, former smokers perceived themselves to be in worse health compared with current smokers.9 A longer duration of abstinence from smoking was associated with less ‘poor health’ perception by former smokers.9 Studies by Wilson et al.10 and Tillman and Silcock11 have shown that smoking cessation leads to improvement in quality-of-life, but the duration of abstinence from smoking (i.e. the time an ex-smoker was abstinent) was not controlled for. In another study, Stewart et al.12 found that those who were not smoking at 6 months scored better on the mental health parameter than those who continued to smoke.
Several investigations have compared perceived health status in smokers and non-smokers. For example, in a non-treatment-based study, Lyons et al.13 found that smokers rated themselves as having worse health status compared with never-smokers in four out of the eight health domains measured on the SF-36. Smokers reported being less physically active, experiencing more body pain, having less vitality and, in general, considered themselves less healthy. There were no differences in limitations due to physical problems, social function, role limitations due to emotional problems or mental health. This has also been confirmed by others.11,14 Furthermore, in a study of hospitalized medical patients, current tobacco users reported poorer health status using the SF-36 compared with non-tobacco users.15
This study aimed to compare the overall perceived health status of patients who abstain from smoking versus those who continue to smoke following an intervention for nicotine dependence at the Mayo Clinic Nicotine Dependence Center (NDC). The study was approved by the Mayo Clinic Institutional Review Board.
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Materials and methods |
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This longitudinal, prospective, cohort study was designed to collect data on patients utilizing the clinical services of the NDC. Baseline information was collected near the time of the initial consultation at the NDC.
Intervention and follow-up
Since 1988, the NDC at Mayo Rochester has provided counsellor-delivered intervention services to patients who were being seen in the medical centre.16
The treatment services have been described in detail elsewhere.16
Follow-up information was collected 1 year after the NDC intervention, using mailed surveys.
Study subjects
Adult NDC patients who utilized the services of the NDC from 1 September 1996 to 31 May 1998 for treatment of cigarette smoking were eligible to participate in this study. In accordance with Minnesota state law, patients who denied general research authorization for access to their medical records were not included.
Measures
Prior to the consultation, the patient completed a demographic and tobacco-use history questionnaire, which the counsellor used to help develop a treatment plan for that patient. Patients were also asked to complete the HSQ and return it by mail. On the 1-year follow-up survey patients were asked to again complete the HSQ and to also provide information regarding their smoking status over the previous year.
The eight subscales of the SF-36 (which is included in the HSQ) are defined as: (1) physical functioning: limitation in physical activity including self-care activities; (2) social functioning limitations in social activities due to physical or emotional problems; (3) role limitation—physical: work and activity limitations due to physical problems; (4) role limitation—emotional: work and activity limitations due to emotional problems; (5) bodily pain: limitations due to pain; (6) mental health: emotional symptoms (e.g. nervous, depressed); (7) vitality: energy versus fatigue; and (8) general health: overall self-rated health.5 As well as the eight subscale scores, there are two SF-36 summary composite scores based on the eight domains: physical composite score and mental composite score. In addition to the SF-36 items, the HSQ includes three questions that are used to screen for depression during the past year.
Statistical analysis
A 7-day time period is commonly used to define point-prevalence abstinence from smoking.17
Patients were considered to have not stopped smoking at all during the year if they indicated that during the prior year the longest time they had gone without smoking was 6 days or less. Patients were considered to have been continuously abstinent for the entire year if they indicated that they had gone without smoking for the entire year. Using these definitions, two distinct smoking outcome groups were identified. For patients who endorsed one of the remaining responses (‘7 to 29 days’, ‘between 1 and 6 months’ and ‘7 months to 1 year’), it is not known when the longest time period of abstinence fell during the intervening year or the number of prolonged stop attempts that the patient experienced. For these reasons, the primary analysis is limited to patients whose longest duration of abstinence was 6 days or less and those who were continuously abstinent for the entire year.
The eight SF-36 subscales were scored and the mental and physical composite scales were calculated using published software.18 To adjust for age and sex differences, the SF-36 scores were standardized using the published age- and sex-specific reference norms for the general US adult population.18 That is, for each individual, a t-score was calculated for each of the SF-36 scales using the mean and standard deviation (SD) of the appropriate age- and sex-matched reference group. t-scores are scaled to have a mean of 50 and a SD of 10 for the reference sample. Thus, the average health-related quality-of-life of the US adult population is represented by a scale t-score of 50, with t-scores higher than 50 reflective of better reported health than the general population and t-scores lower than 50 reflective of perceived worse health than the general population. In addition to the SF-36 items, the HSQ contains three items that are used to screen for depression during the past year and were scored according to published guidelines.8,19
Baseline characteristics were compared between smoking outcome groups using the two-sample t-test for continuous variables and the 
2 (or an exact test) for categorical variables. Differences between smoking outcome groups at 1 year following the consultation were assessed for the two SF-36 composite scales (mental and physical) using multivariate analysis of covariance (MANCOVA) with baseline composite scores included as covariates. To supplement analysis of the composite scales, additional analyses were performed for the eight SF-36 subscales. Since smoking outcome groups differed significantly with respect to stage of change and location of consultation, additional analyses were performed with these variables included as covariates. In order to assess potential biases impacting the generalizability of the study findings, two analyses were performed. Baseline demographic variables were compared between eligible patients that did and did not complete a baseline HSQ at the time of the NDC consult. In addition, for patients who completed the baseline HSQ, a similar analysis was performed to compare baseline demographic variables of those who did and did not return follow-up surveys at 1 year. For these analyses, groups were compared using the two-sample t-test for continuous variables and the 2-test for categorical variables. In all cases, two-sided tests were used with P-values 
0.05 and considered statistically significant.
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Results |
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During the study period, a total of 3333 eligible patients utilized the services of the NDC, of whom 1519 (46%) completed a baseline HSQ at or near the time of their initial consult (median 16 days following consultation). Of the 1519 eligible patients who completed a baseline questionnaire, 362 (24%) returned both the standard follow-up questionnaire and the HSQ at 1 year. For these 362 patients, 14 patients did not provide information on the longest time period of abstinence in the past year. Of those who responded, 26 endorsed ‘less than 24 h or not at all’, 34 endorsed ‘1 to 6 days’, 28 endorsed ‘7 to 29 days’, 68 endorsed ‘between 1 and 6 months’, 46 endorsed ‘between 7 months and 1 year’ and 146 endorsed ‘for the entire year’. The 60 patients who reported their longest period of smoking abstinence in the past year was 6 days or less and the 146 patients who reported continuous abstinence for the entire year represent the smoking outcome groups used for the primary analyses.
Representativeness of study patients
To determine how representative the study sample is of the overall NDC population, analyses were performed to compare those who completed a baseline HSQ with the larger group of all eligible patients seen at the NDC during the study period. Of the 3333 eligible patients seen during the study period (48% female), the mean age ± SD was 48.1 ± 13.9 years. Most patients (53%) were smoking 20–39 cigarettes per day, and 68% were married. Regarding stage of change, 31% were in action, 31% preparation, 33% contemplation and 5% in precontemplation. For the location of the consultation, 49% were seen at an outpatient clinic, 24% were at the NDC, 23% were in a hospital and 3% were in a residential nicotine treatment programme. A total of 1519 patients (50% male; age 49.5 ± 13.1 years) completed a baseline questionnaire. Patients who completed a baseline HSQ were significantly older (P<0.001) than those who did not complete a questionnaire, and were more likely to be married (P=0.008), have more advanced stage of change (P=0.011) and be seen while hospitalized or as part of the residential nicotine-dependence treatment programme (P=0.001).
Of the 362 patients who completed both a baseline questionnaire and the 1-year follow-up survey (50% male), the mean age ± SD was 52.4 ± 12.6 years, most (48%) were smoking 20–39 cigarettes per day and 73% were married. With respect to stage of change, 39% were in action, 31% preparation, 25% contemplation and 4% precontemplation. Regarding the location of the consultation, 48% were seen at an outpatient clinic, 20% at the NDC, 22% in a hospital and 11% in a residential nicotine treatment programme. Patients who completed both a baseline questionnaire and the 1-year follow-up survey were significantly older (P<0.001) than those who completed only a baseline HSQ. Significant differences were also detected with respect to stage of change (P=0.011) and location of provided service (P<0.001).
Baseline characteristics by smoking outcome group
The baseline characteristics of the two smoking outcome groups are presented in table 1. The groups were similar for all variables with the exception of stage of change and location of the consultation (P<0.001 in both cases). Of patients who remained abstinent for the entire year, only 17% were in the precontemplation or contemplation stage of change at baseline, compared with 52% of patients who continued to smoke. Of those who remained abstinent for the entire year, 32% were seen in the hospital and 16% were seen in the residential nicotine-dependence treatment programme. In those who continued to smoke, the corresponding percentages were 13% and 0%, respectively.
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Health status by smoking outcome group
At baseline, patients who did not stop smoking had mean t-scores significantly less than 50 for all SF-36 scales except role limitation—emotional (one-sample t-test, P
0.05), and patients that stopped smoking for the entire year had mean t-scores that were significantly less than 50 for all SF-36 scales except bodily pain (P0.05). Thus, for both groups, the average perceived health at baseline was significantly worse than that for the general population. Although mental composite scores were similar at baseline (P=0.842), patients that stopped smoking for the entire year had a higher mean baseline physical composite score than patients that continued to smoke (P=0.017). From analysis of the eight subscale scores, those that remained abstinent for the entire year were found to have better baseline health status than those that continued to smoke, for the subscales of general health (P=0.023), physical functioning (P=0.040) and bodily pain (P=0.017). At 1 year following the consultation, health status assessed using the SF-36 composite scales differed significantly between groups (MANCOVA, P<0.001). After adjusting for baseline scores, baseline stage of change and location of consultation, patients that had remained abstinent for the entire year were found to have significantly (P=0.009) improved mental composite scores compared with those that continued to smoke. From analysis of the individual subscale scores, the patients that remained abstinent for the entire year were found to experience a more positive change for role limitations (P<0.001 and P=0.017 for emotional and physical role limitations, respectively), social functioning (P=0.010) and general health (P=0.013). The frequency of self-reported depression (table 2) was not significantly different between groups at baseline (15/60 versus 20/142, P=0.061) or 1 year (14/59 versus 23/143, P=0.201).
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Discussion |
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The major finding of this study is that cigarette smokers who receive a clinical smoking cessation intervention and who are continuously abstinent from smoking for the subsequent year report more improvement in the SF-36 mental health composite score at the end of that year compared with those who continue to smoke. For the smokers included in this report, the average perceived health status at baseline was significantly worse than that of the general population. This is consistent with findings by Lyons et al.,13 Patten et al.15 and Mulder et al.,20 who found that smokers report poorer health status in general than never and former smokers. Of the eight individual subscales, the ones most affected were mental health, role limitations due to emotional problems, general health, role limitations due to physical problems and social functioning. Our results also indicate that the frequency of self-reported depression as measured by the HSQ in this study was not significantly different between the ‘extreme’ groups (continued smoking versus continuous abstinence) at baseline or 1 year. These findings are somewhat inconsistent with previous investigations,15 but consistent with the study by Mulder et al.20
In a one-time random sample of the RAND-36 (adapted from the SF-36), quality-of-life was compared between never, former and current smokers. In many instances, especially with reference to mental health and role limitations due to emotional problems, smokers had worse scores than ex-smokers. These findings were again reproduced in a cluster analysis of smokers and ex-smokers by Wilson et al.10 In that study, 3010 people completed the SF-36 and again results indicated that smokers did worse for all mental health dimensions than ex-smokers. Another study by Zillich et al.21 also used a one-time survey of health-related quality-of-life and also demonstrated similar findings whereby patients who quit smoking during a 3-month program showed considerable improvement in mental health scores.
A limitation of our study and others (Mulder et al.,20 Wilson et al.10 and Zillich et al.21 ) is that the definition of smoking abstinence relied on self-report, and only patients who responded to the follow-up survey were included. Velicer et al.22 found that the self-reported smoking status is generally highly accurate in smokers. The exception being for clinic or intensive intervention studies or for high-risk or medical patients, in whom the rate of misreporting is greater due to higher expectations. Thus, future studies should attempt to confirm self-reported smoking abstinence. In addition, although the sample of patients included in this investigation is fairly representative of the overall mix of patients seen at the NDC, the mean age of the sample was slightly older and the patients were more likely to have had a more advanced stage of change at baseline. Also, 11% of the patients included in our primary analysis were seen as part of a residential treatment programme, compared with only 3% of all patients seen at the NDC. Furthermore, of patients included in the sample, more of those who were abstinent for the entire year were seen in a residential nicotine treatment programme or while hospitalized for another reason. Although these variables were included as covariates in the analysis, it is possible that hospitalized patients or patients seen during a health care encounter for a medical problem other than smoking might have a lower health status at baseline that is improved due to treatment other than stopping smoking.
An additional limitation is that this study focused on two distinct groups: former smokers stopped for 1 year and current smokers. For those that did not fit into one of these groups, we did not have adequate information to determine the total time they were abstinent from smoking during the year following treatment. Thus far, only the cluster analysis performed by Mulder et al.20 has been able to adequately demonstrate any kind of effect that time since quitting has on quality-of-life. Future investigations should assess smoking status and perceived health status concurrently at various time points following treatment up to 1 year. Finally, it would have been ideal to include a third group of patients in our study comprised of never smokers.
Improvement in health status has recently been identified as an outcome criterion for the effectiveness of treatment for addictions.23 Previous work has shown that a clinical intervention programme for nicotine dependence not only can improve abstinence outcomes,24–26 but also is highly cost-effective compared with many standard medical practices.4 The current work illustrates smoking abstinence-related improvement in quality-of-life, especially dimensions related to mental health, as assessed by the SF-36. The results from this analysis can add to the education of the smoking patient and in turn contribute to smoking cessation efforts. These results are more than a comparison of ex-smokers versus smokers, in that they specifically demonstrate improvement in quality-of-life with 1 year of continuous abstinence from smoking.
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Acknowledgments |
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A special thanks to Mr Kenneth P. Offord for his helpful input into the study design and interpretation of the results. Also, thanks to Ms Patricia L. Fisher, Mr Thomas R. Gauvin and Ms Adrienne S. Dormody, all of whom are exceptional nicotine-dependence counsellors at the Mayo Clinic Nicotine Dependence Center and who aided in data collection. In addition, the authors wish to thank Ms Judith Trautman, Debi Judy, Ann B. Peterson and Leigh Gomez-Dahl for their patience and persistence in helping collect, compile and organize these data, and without whose data management skills, this study and final manuscript production would not have been possible. This programme was supported in part by grant 561-546-9907 from the Mayo Foundation.
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1 US Department of Health and Human Services. The health consequences of smoking for women: A report of the Surgeon General. DHHS Publication No (CDC) 80-396. Washington, DC: US Department of Health and Human Services, US Government Printing Office, 1980.
2 Tarlov AR. Tobacco use and the quality of life. Tob Control 1994;3:196.
3 Centers for Disease Control and Prevention. State tobacco control highlights. NCCDPHP. Report No. 099-4895. Atlanta, GA: Office of Smoking and Health, 1996.
4 Croghan IT, Offord KP, Evans RW, et al. Cost-effectiveness of treating nicotine dependence: the Mayo Clinic experience. Mayo Clin Proc 1997;72:917–24.[Abstract]
5 Ware JE, Snow KK, Evans RW, et al. SF-36 health survey: manual and interpretation guide. Boston, MA: The Health Institute, 1993.
6 Hawker G, Melfi C, Paul J, et al. Comparison of a generic (SF-36) and a disease specific (WOMAC) (Western Ontario and McMaster Universities Osteoarthritis Index) instrument in the measurement of outcomes after knee replacement surgery. J Rheumatol 1995;22:1193–6.[Web of Science][Medline]
7 Bombardier C, Melfi C, Paul J, et al. Comparison of a generic and a disease-specific measure of pain and physical function after knee replacement surgery. Med Care 1995;33 (4 Suppl):AS131–44.[Web of Science][Medline]
8 Radosevich DM, Wetzler H, Wilson SM. Health Status Questionnaire (HSQ) 2.0: scoring comparisons and reference data. Bloomington, MN: Health Outcomes Institute, 1994.
9 Halpern MT, Warner KE. Differences in former smokers' beliefs and health status following smoking cessation. Am J Prev Med 1994;10:31–7.[Web of Science][Medline]
10 Wilson D, Parsons J, Wakefield M. The health-related quality of life of never-smokers, ex-smokers and light, moderate and heavy smokers. Prev Med 1999;29:139–44.[CrossRef][Web of Science][Medline]
11 Tillman M, Silcock J. A comparison of smokers' and ex-smokers' health-related quality of life. J Public Health Med 1997;19:268–73.
12 Stewart AL, King AC, Killen JD, Ritter PL. Does smoking cessation improve health-related quality-of-life? Ann Behav Med 1995;17:331–8.
13 Lyons RA, Lo SV, Littlepage BNC. Perception of health amongst ever-smokers and never-smokers: a comparison using the SF-36 Health Survey Questionnaire. Tob Control 1994;3:213–5.
14 Segovia J, Bartlet RF, Edwards AC. The association between self-assessed health status and individual health practices. Can J Public Health 1989;80:32–7.[Web of Science][Medline]
15 Patten CA, Schneekloth TD, Morse RM, et al. Effect of current tobacco use and history of an alcohol problem on health status in hospitalized patients. Addict Behav 2001;26:129–36.[CrossRef][Web of Science][Medline]
16 Hurt RD, Dale LC, McClain FL, et al. A comprehensive model for the treatment of nicotine dependence in a medical setting. Med Clin North Am 1992;76:495–514.[Web of Science][Medline]
17 Hughes JR, Keely JP, Niaura RS, et al. Measures of abstinence in clinical trials: issues and recommendations. Nicotine Tob Res 2003;5:13–25.[CrossRef][Web of Science][Medline]
18 Ware JE, Kosinski M, Keller SD. SF-36 physical and mental health summary scales: a user's manual. Boston, MA: The Health Institute, 1994.
19 Rost K, Burnam MA, Smith GR. Development of screeners for depressive disorders and substance disorder history. Med Care 1993;31:189–200.[Web of Science][Medline]
20 Mulder I, Tijhuis M, Smit HA, Kromhout D. Smoking cessation and quality of life: the effect of amount of smoking and time since quitting. Prev Med 2001;33:653–60.[CrossRef][Web of Science][Medline]
21 Zillich AJ, Ryan M, Adams A, et al. Effectiveness of a pharmacist-based smoking-cessation program and its impact on quality of life. Pharmacotherapy 2002;22:759–65.[CrossRef][Web of Science][Medline]
22 Velicer WF, Prochaska JO, Rossi JS, Snow MG. Assessing outcome in smoking cessation studies. Psychol Bull 1992;111:23–41.[CrossRef][Web of Science][Medline]
23 McLellan AT, Woody GE, Metzger D. Evaluating the effectiveness of addiction treatment: reasonable expectation, approaches, and comparisons. Milbank Q 1996;74:51–85.[CrossRef][Web of Science][Medline]
24 Hays JT, Wolter TD, Eberman KM, et al. Residential (inpatient) treatment compared to outpatient treatment for nicotine dependence. Mayo Clin Proc 2001;76:124–33.[Abstract]
25 Hays JT, Dale LC, Hurt RD, Croghan IT. Trends in smoking-related diseases: why smoking cessation is still the best medicine. Postgrad Med 1998;104:56–71.
26 Dale LC, Hurt RD, Hays JT. Drug therapy to aid in smoking cessation: tips on maximizing patients; chances for success. Postgrad Med 1998;104:75–84.
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