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Interventions to increase adherence to medications for tobacco dependence. BACKGROUND: Pharmacological treatments for tobacco dependence, such as nicotine replacement therapy (NRT), have been shown to be safe and effective interventions for smoking cessation. Higher levels of adherence to these medications increase the likelihood of sustained smoking cessation, but many smokers use them at a lower dose and for less time than is optimal. It is important to determine the effectiveness of interventions designed specifically to increase medication adherence. Such interventions may address motivation to use medication, such as influencing beliefs about the value of taking medications, or provide support to overcome problems with maintaining adherence. OBJECTIVES: To assess the effectiveness of interventions aiming to increase adherence to medications for smoking cessation on medication adherence and smoking abstinence compared with a control group typically receiving standard care. SEARCH METHODS: We searched the Cochrane Tobacco Addiction Group Specialized Register, and clinical trial registries (ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform) to the 3 September 2018. We also conducted forward and backward citation searches. SELECTION CRITERIA: Randomised, cluster-randomised or quasi-randomised studies in which adults using active pharmacological treatment for smoking cessation were allocated to an intervention arm where there was a principal focus on increasing adherence to medications for tobacco dependence, or a control arm providing standard care. Dependent on setting, standard care may have comprised minimal support or varying degrees of behavioural support. Included studies used a measure that allowed assessment of the degree of medication adherence. DATA COLLECTION AND ANALYSIS: Two authors independently screened studies for eligibility, extracted data for included studies and assessed risk of bias. For continuous outcome measures, we calculated effect sizes as standardised mean differences (SMDs). For dichotomous outcome measures, we calculated effect sizes as risk ratios (RRs). In meta-analyses for adherence outcomes, we combined dichotomous and continuous data using the generic inverse variance method and reported pooled effect sizes as SMDs; for abstinence outcomes, we reported and pooled dichotomous outcomes. We obtained pooled effect sizes with 95% confidence intervals (CIs) using random-effects models. We conducted subgroup analyses to assess whether the primary focus of the adherence treatment ('practicalities' versus 'perceptions' versus both), the delivery approach (participant versus clinician-centred) or the medication type were associated with effectiveness. MAIN RESULTS: We identified two new studies, giving a total of 10 studies, involving 3655 participants. The medication adherence interventions studied were all provided in addition to standard behavioural support.They typically provided further information on the rationale for, and emphasised the importance of, adherence to medication or supported the development of strategies to overcome problems with maintaining adherence (or both). Seven studies targeted adherence to NRT, two to bupropion and one to varenicline. Most studies were judged to be at high or unclear risk of bias, with four of these studies judged at high risk of attrition or detection bias. Only one study was judged to be at low risk of bias.Meta-analysis of all 10 included studies (12 comparisons) provided moderate-certainty evidence that adherence interventions led to small improvements in adherence (i.e. the mean amount of medication consumed; SMD 0.10, 95% CI 0.03 to 0.18; I² = 6%; n = 3655), limited by risk of bias. Subgroup analyses for the primary outcome identified no significant subgroup effects, with effect sizes for subgroups imprecisely estimated. However, there was a very weak indication that interventions focused on the 'practicalities' of adhering to treatment (i.e. capabilities, resources, levels of support or skills) may be effective (SMD 0.21, 95% CI 0.03 to 0.38; I² = 39%; n = 1752), whereas interventions focused on treatment 'perceptions' (i.e. beliefs, cognitions, concerns and preferences; SMD 0.10, 95% CI -0.03 to 0.24; I² = 0%; n = 839) or on both (SMD 0.04, 95% CI -0.08 to 0.16; I² = 0%; n = 1064), may not be effective. Participant-centred interventions may be effective (SMD 0.12, 95% CI 0.02 to 0.23; I² = 20%; n = 2791), whereas those that are clinician-centred may not (SMD 0.09, 95% CI -0.05 to 0.23; I² = 0%; n = 864).Five studies assessed short-term smoking abstinence (five comparisons), while an overlapping set of five studies (seven comparisons) assessed long-term smoking abstinence of six months or more. Meta-analyses resulted in low-certainty evidence that adherence interventions may slightly increase short-term smoking cessation rates (RR 1.08, 95% CI 0.96 to 1.21; I² = 0%; n = 1795) and long-term smoking cessation rates (RR 1.16, 95% CI 0.96 to 1.40; I² = 48%; n = 3593). In both cases, the evidence was limited by risk of bias and imprecision, with CIs encompassing minimal harm as well as moderate benefit, and a high likelihood that further evidence will change the estimate of the effect. There was no evidence that interventions to increase adherence to medication led to any adverse events. Studies did not report on factors plausibly associated with increases in adherence, such as self-efficacy, understanding of and attitudes toward treatment, and motivation and intentions to quit. AUTHORS' CONCLUSIONS: In people who are stopping smoking and receiving behavioural support, there is moderate-certainty evidence that enhanced behavioural support focusing on adherence to smoking cessation medications can modestly improve adherence. There is only low-certainty evidence that this may slightly improve the likelihood of cessation in the shorter or longer-term. Interventions to increase adherence can aim to address the practicalities of taking medication, change perceptions about medication, such as reasons to take it or concerns about doing so, or both. However, there is currently insufficient evidence to confirm which approach is more effective. There is no evidence on whether such interventions are effective for people who are stopping smoking without standard behavioural support.

Interventions to increase adherence to medications for tobacco dependence. BACKGROUND: Pharmacological treatments for tobacco dependence, such as nicotine replacement therapy (NRT), have been shown to be safe and effective interventions for smoking cessation. Higher levels of adherence to these medications increase the likelihood of sustained smoking cessation, but many smokers use them at a lower dose and for less time than is optimal. It is therefore important to determine the effectiveness of interventions designed specifically to increase medication adherence. Such interventions may include further educating individuals about the value of taking medications and providing additional support to overcome problems with maintaining adherence. OBJECTIVES: The primary objective of this review was to assess the effectiveness of interventions to increase adherence to medications for smoking cessation, such as NRT, bupropion, nortriptyline and varenicline (and combination regimens). This was considered in comparison to a control group, typically representing standard care. Secondary objectives were to i) assess which intervention approaches are most effective; ii) determine the impact of interventions on potential precursors of adherence, such as understanding of the treatment and efficacy perceptions; and iii) evaluate key outcomes influenced by prior adherence, principally smoking cessation. SEARCH METHODS: We searched the following databases using keywords and medical subject headings: Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE (OVID SP) (1946 to July Week 3 2014), EMBASE (OVID SP) (1980 to Week 29 2014), and PsycINFO (OVID SP) (1806 to July Week 4 2014). The Cochrane Tobacco Addiction Group Specialized Register was searched on 9th July 2014. We conducted forward and backward citation searches. SELECTION CRITERIA: Randomised, cluster-randomised or quasi-randomised studies in which participants using active pharmacological treatment for smoking cessation are allocated to an intervention arm or a control arm. Eligible participants were adult (18+) smokers. Eligible interventions comprised any intervention that differed from standard care, and where the intervention content had a clear principal focus on increasing adherence to medications for tobacco dependence. Acceptable comparison groups were those that provided standard care, which depending on setting may comprise minimal support or varying degrees of behavioural support. Included studies used a measure of adherence behaviour that allowed some assessment of the degree of adherence. DATA COLLECTION AND ANALYSIS: Two review authors searched for studies and independently extracted data for included studies. Risk of bias was assessed according to the Cochrane Handbook guidance. For continuous outcome measures, we report effect sizes as standardised mean differences (SMDs). For dichotomous outcome measures, we report effect sizes as relative risks (RRs). We obtained pooled effect sizes with 95% confidence intervals (CIs) using the fixed effects model. MAIN RESULTS: Our search strategy retrieved 3165 unique references and we identified 31 studies as potentially eligible for inclusion. Of these, 23 studies were excluded at full-text screening stage or identified as studies awaiting classification subject to further information. We included eight studies involving 3336 randomised participants. The interventions were all additional to standard behavioural support and typically provided further information on the rationale for, and emphasised the importance of, adherence to medication, and supported the development of strategies to overcome problems with maintaining adherence.Five studies reported on whether or not participants achieved a specified satisfactory level of adherence to medication. There was evidence that adherence interventions led to modest improvements in adherence, with a relative risk (RR) of 1.14 (95% CI, 1.02 to 1.28, P = 0.02, n = 1630). Four studies reported continuous measures of adherence to medication. Although the standardised mean difference (SMD) favoured adherence interventions, the effect was small and not statistically significant (SMD 0.07, 95% CI, -0.03 to 0.17, n = 1529). Applying the GRADE system, the quality of evidence for these results was assessed as moderate and low, respectively.There was evidence that adherence interventions led to modest improvements in rates of cessation. The relative risk for achieving abstinence was similar to that for improved adherence. It was not significant in meta-analysis of four studies providing short-term abstinence: RR = 1.07 (95% CI 0.95 to 1.21, n = 1755), but there was statistically significant evidence of improved abstinence at six months or more from a different set of four studies: RR = 1.16 (95% CI, 1.01 to 1.34, P = 0.03, n = 3049). Applying the GRADE system, the quality of evidence for these results was assessed as low for both.As interventions were similar in nature and the number of studies was low, it was not possible to investigate whether different types of intervention approaches were more effective than others. Relevant outcomes other than adherence or cessation were not reported.There was no evidence that interventions to increase adherence to medication led to any adverse events. All included studies were assessed as at high or unclear risk of bias. This was often due to a lack of clarity in reporting - meaning assessments were unclear - rather than clear evidence of failing to sufficiently safeguard against the risk of bias. AUTHORS' CONCLUSIONS: There is some evidence that interventions that devote special attention to improving adherence to smoking cessation medication through providing information and facilitating problem-solving can improve adherence, though the evidence for this is not strong and is limited in both quality and quantity. There is some evidence that such interventions improve the chances of achieving abstinence but again the evidence for this is relatively weak.