Background: Tobacco dependence is a chronic, relapsing condition that may require extended treatment.
Objective: To assess whether extended transdermal nicotine therapy increases abstinence from tobacco more than standard duration therapy in adult smokers.
Design: Parallel randomized placebo-controlled trial from September 2004 to February 2008 (small block randomization scheme, not stratified). Study participants and all research personnel except for the database manager were blinded to randomization. (NCT00364156)
Setting: Academic center.
Participants: 568 adult smokers.
Intervention: Participants were randomized to: standard (8 weeks 21mg Nicoderm CQ, 16 weeks placebo) or extended (24 weeks 21mg Nicoderm CQ) therapy.
Measurements: The primary outcome was biochemically-verified point prevalence abstinence at weeks 24 and 52. Secondary outcomes were continuous and prolonged abstinence, lapse and recovery events, cost/additional quitter, and side effects and adherence.
Results: At 24 weeks, extended therapy produced higher rates of point prevalence abstinence (31.6% versus 20.3%; Odds Ratio [OR] = 1.81 [1.23-2.66], p = 0.002), prolonged abstinence (41.5% versus 26.9%; OR = 1.97 [1.38-2.82] p = 0.001), and continuous abstinence (19.2% versus 12.6%; OR = 1.64 [1.04-2.60] p = 0.032), versus standard therapy. Extended therapy reduced the risk for a lapse (Hazard Ratio [HR] = 0.77 [0.63-0.95], p = 0.013) and increased the chances of recovery from lapses (HR = 1.47 [1.17-1.84], p = 0.001). Time to relapse was slower with extended versus standard therapy (HR = 0.50 [0.35-0.73], p < 0.001). At week 52, extended therapy produced higher quit rates for prolonged abstinence only (p = 0.027). There were no group differences in side effects and adverse events at the extended treatment phase assessment.
Limitations: The generalizability of the findings may be limited because participants were treatment-seeking smokers without medical comorbidity and differences in adherence across treatment arms were detected.
Conclusion: Compared to 8 weeks of transdermal nicotine, 24 weeks of transdermal nicotine increased biochemically-confirmed point prevalence abstinence and continuous abstinence at week 24, reduced the risk of smoking lapses, and increased the likelihood of post-lapse recovery to abstinence.
The rate of smokeless tobacco use in India is 20%; its use causes serious health problems, and no trial has assessed behavioral or pharmacological treatments for this public health concern. This trial evaluated varenicline for treating smokeless tobacco dependence in India.
This was a double-blind placebo-controlled randomized trial of varenicline (12 weeks, 1mg, twice per day) with 237 smokeless tobacco users in India. All participants received behavioral counseling. Outcomes included self-reported and biochemically verified abstinence at the end of treatment (EOT), lapse and recovery events, safety, and medication adherence.
Self-reported EOT abstinence was significantly greater for varenicline (43%) versus placebo (31%; adjusted odds ratio [AOR] = 2.6, 95% CI = 1.2–4.2, p = .009). Biochemically confirmed EOT abstinence was greater for varenicline versus placebo (25.2% vs. 19.5%), but this was not statistically different (AOR = 1.6, 95% CI = 0.84–3.1, p = .15). Compared with placebo, varenicline did not reduce the risk for a lapse (hazard ratio [HR] = 0.86, 95% CI = 0.69–1.1, p = .14), but it did increase the likelihood of recovery to abstinence (HR = 1.2, 95% CI = 1.02–1.4, p = .02). Greater adherence increased EOT cessation rates for varenicline (39% vs. 18%, p = .003) but not for placebo (28% vs. 14%, p = .06). There were no significant differences between varenicline and placebo in rate of side effects, serious adverse events, hypertension, or stopping or reducing medication.
Varenicline is safe for treating smokeless tobacco dependence in India, and further examination of this medication for this important public health problem is warranted.
Cigarette smoking is associated with a higher prevalence of depressive symptoms and individuals with elevated symptoms of depression have more difficulty quitting smoking. Depression is accompanied by cognitive deficits similar to those observed during nicotine withdrawal. Depressed smokers may smoke to alleviate these cognitive symptoms, which are exacerbated upon smoking abstinence. We hypothesized that following overnight abstinence, depression-prone smokers (DP+; past history and current depression symptoms; n = 34) would exhibit deficits in short-term and working memory, and experience greater attentional bias for affective stimuli, compared with smokers with no history or current symptoms of depression (DP−; n = 34). All participants underwent two laboratory sessions, once while smoking abstinent and once while smoking ad libitum (order counterbalanced, abstinence biochemically verified). Smokers completed measures of short-term memory (STM; word recognition task), working memory (N-back task), and attentional bias (Emotional Stroop task). The DP+ group showed declines in STM during abstinence compared with smoking, whereas the DP− group did not (interaction p = .02). There were small decrements in working memory accuracy during abstinence (p = .05), but this did not interact with depression status. During the Emotional Stroop task, the DP+ group showed an attentional bias toward positive versus neutral stimuli during abstinence compared with smoking (interaction p = .01). This study provides initial evidence that depressive symptoms may moderate abstinence-induced deficits in STM and shift attentional bias toward emotionally salient stimuli during abstinence. These cognitive changes may prompt relapse and may help identify novel targets for nicotine dependence treatment aimed at attenuating these deficits to improve cessation rates.
smoking; depression; memory; attentional bias; nicotine withdrawal
Dopamine levels in the prefrontal cortex (PFC) are thought to play an important role in cognitive function and nicotine dependence. The catechol-O-methyltransferase (COMT) inhibitor tolcapone, an FDA-approved treatment for Parkinson’s disease, increases prefrontal dopamine levels, with cognitive benefits that may vary by COMT genotype. We tested whether tolcapone alters working memory-related brain activity and performance in abstinent smokers.
In this double-blind crossover study, 20 smokers completed 8 days of treatment with tolcapone and placebo. In both medication periods, smokers completed blood oxygen level-dependent (BOLD) fMRI scans while performing a working memory N-back task after 24 h of abstinence. Smokers were genotyped prospectively for the COMT val158met polymorphism for exploratory analysis.
Compared to placebo, tolcapone modestly improved accuracy (p = 0.017) and enhanced suppression of activation in the ventromedial prefrontal cortex (vmPFC) (p = 0.002). There were no effects of medication in other a priori regions of interest (dorsolateral PFC, dorsal cingulate/medial prefrontal cortex, or posterior cingulate cortex). Exploratory analyses suggested that tolcapone led to a decrease in BOLD signal in several regions among smokers with val/val genotypes, but increased or remained unchanged among met allele carriers. Tolcapone did not attenuate craving, mood, or withdrawal symptoms compared to placebo.
Data from this proof-of-concept study do not provide strong support for further evaluation of COMT inhibitors as smoking cessation aids.
Smoking; Nicotine; COMT; Tolcapone; fMRI; Working memory
Most smokers do not utilize approved interventions for nicotine dependence, reducing the probability of cessation. Smoking cessation programs typically use recruitment messages emphasizing the health threats of smoking. Augmenting this threat message by describing the genetic aspects of nicotine addiction may enhance enrollment into a cessation program. During telephone recruitment, 125 treatment-seeking smokers were randomized to receive by phone either a standard threat message or a threat plus genetic prime message and were offered open-label varenicline and counseling. There was a greater rate of enrollment into the cessation program for the threat plus genetic prime participants (51.7%) vs. the threat-only participants (37.7%; p = .03). Smokers who self-identified from racial/ethnic minority groups were less likely to enroll in the cessation program (p = .01) vs. smokers who self-identified as Caucasian. These preliminary data suggest that a simple, affordable, and transportable communication approach enhances enrollment of smokers into a smoking cessation program. A larger clinical trial to evaluate a genetic prime message for improving recruitment into smoking cessation programs is warranted.
Although prior authorization and prospective audit with feedback are both effective antimicrobial stewardship program (ASP) strategies, the relative impact of these approaches remains unclear. We compared these core ASP strategies at an academic medical center.
We compared antimicrobial use during the 24 months before and after implementation of an ASP strategy change. The ASP used prior authorization alone during the preintervention period, June 2007 through May 2009. In June 2009, many antimicrobials were unrestricted and prospective audit was implemented for cefepime, piperacillin/tazobactam, and vancomycin, marking the start of the postintervention period, July 2009 through June 2011. All adult inpatients who received more than or equal to 1 dose of an antimicrobial were included. The primary end point was antimicrobial consumption in days of therapy per 1,000 patient-days (DOT/1,000-PD). Secondary end points included length of stay (LOS).
In total, 55,336 patients were included (29,660 preintervention and 25,676 postintervention). During the preintervention period, both total systemic antimicrobial use (−9.75 DOT/1,000-PD per month) and broad-spectrum anti-gram-negative antimicrobial use (−4.00 DOT/1,000-PD) declined. After the introduction of prospective audit with feedback, however, both total antimicrobial use (+9.65 DOT/1,000-PD per month; P < .001) and broad-spectrum anti-gram-negative antimicrobial use (+4.80 DOT/1,000-PD per month; P < .001) increased significantly. Use of cefepime and piperacillin/tazobactam both significantly increased after the intervention (P = .03). Hospital LOS and LOS after first antimicrobial dose also significantly increased after the intervention (P = .016 and .004, respectively).
Significant increases in antimicrobial consumption and LOS were observed after the change in ASP strategy.
Individual differences in the evaluation of affective stimuli, such as the positivity offset and negativity bias may have a biological basis. We tested whether two SNPs (HTR2A; 102T>C and HTR1A; 1019C>G) related to serotonin receptor function, a biological pathway associated with affective regulation, were differentially related to positivity offset and negativity bias for males and females. Participants were 109 cigarette smokers who rated a series of affective stimuli to assess reactions to positive and negative pictures. Gender × genotype interactions were found for both SNPs. Males with the 102T allele showed a greater positivity offset than males with the 102C allele. For females, in contrast, the 1019C allele was associated with a greater positivity offset than the 1019G allele, whereas the 102T allele was associated with a greater negativity bias than the 102C allele. Identifying how gender differences may moderate the effect of serotonin receptor genes on affective information processing may provide insight into their role in guiding behavior and regulating affect.
Cognitive Processes; Affect regulation; Negativity bias; Positivity bias; Gender; Serotonin receptor gene
Blood tests to detect circulating tumor cells (CTC) offer great potential to monitor disease status, gauge prognosis, and guide treatment decisions for patients with cancer. For patients with brain tumors, such as aggressive glioblastoma multiforme, CTC assays are needed that do not rely on expression of cancer cell surface biomarkers like epithelial cell adhesion molecules that brain tumors tend to lack. Here, we describe a strategy to detect CTC based on telomerase activity, which is elevated in nearly all tumor cells but not normal cells. This strategy uses an adenoviral detection system that is shown to successfully detect CTC in patients with brain tumors. Clinical data suggest that this assay might assist interpretation of treatment response in patients receiving radiotherapy, for example, to differentiate pseudoprogression from true tumor progression. These results support further development of this assay as a generalized method to detect CTC in patients with cancer.
This study examined a cancer diagnosis, vs. orthopedic surgery, as a teachable moment for recruiting smokers and treating nicotine dependence among patients’ relatives.
Cancer patients and, for comparison, orthopedic patients at the University of Pennsylvania Health System were approached for referrals of relatives for a smoking cessation program, which involved behavioral counseling and nicotine patches. Primary outcomes were rate of program enrollment and rate of smoking abstinence. Potential mediators of smoking cessation were explored (e.g., treatment adherence, depression, anxiety). Two-hundred thirty four relatives (113 cancer, 121 orthopedic) were considered eligible for the cessation program and comprised the study sample.
Relatives of oncology patients were significantly more likely to enroll in the smoking cessation program, vs. orthopedic relatives (75% vs. 60%; OR=1.96, 95% CI: 1.07-3.61, p=.03) but they were not significantly more likely to remain in the program (61% vs. 52%) or quit smoking (19% vs. 26%;
p’s > .05). Compared to orthopedic relatives, oncology relatives showed significantly lower nicotine patch adherence and significantly greater levels of negative affect and depression and anxiety symptoms during treatment (p’s < .05). Further, orthopedic relatives, compared to oncology relatives, showed a greater reduction in the perceived benefits of smoking (p=.06), which was significantly associated with abstinence (p=.02).
While a family member’s cancer diagnosis may serve as a teachable moment for a smoker to enroll in a smoking cessation treatment program, high levels of psychological distress and perceptions of the benefits of smoking and low levels of treatment adherence may undermine successful abstinence among this population.
Teachable moment; cancer; smoking cessation
There is a critical need for the development of novel treatments for nicotine dependence. Since the majority of smokers who make a quit attempt fail within seven days, medication screening procedures which focus on this early cessation period may provide an indicator of treatment efficacy. To establish the clinical validity of this paradigm, it is critical to demonstrate the association of early abstinence with longer-term abstinence. We tested the number of days abstinent during the first week following the target quit date (TQD) as a predictor of point-prevalence abstinence in three independent pharmacotherapy trials for nicotine dependence.
This was a secondary data analysis of three randomized clinical trials: a placebo-controlled trial of transdermal nicotine (n=545); an open-label nicotine replacement therapy (patch vs. spray) trial (n=566); and a bupropion placebo-controlled trial (n=538). In separate logistic regression models, the maximum number of consecutive days of abstinence during the first week following the TQD was used to predict biochemically-verified 7-day point prevalence abstinence at end-of-treatment and six months post-TQD.
Across the three trials, number of days abstinent significantly predicted abstinence at end-of-treatment and six months (ORs>1.4, ps<0.0001). Likewise, not having any lapse during the first week predicted abstinence at end-of-treatment and six months (ORs>4.7, ps<0.0001).
The first week of abstinence was highly predictive of end-of-treatment and long-term abstinence. Medication screening procedures which focus on this early abstinence period (i.e., six or seven days of consecutive abstinence) represent a valid tool for assessing the presence of a signal for medication efficacy.
Smoking cessation; nicotine dependence; medication screening; relapse
Possessing an APOE ε4 allele, advanced age, and smoking are risk factors for Alzheimer’s disease and cognitive decline. Deficits in cognitive function also increase risk for smoking relapse. Data from 917 adult smokers of European ancestry were pooled across three randomized trials of smoking cessation. We examined whether smokers who carry at least one ε4 allele (n=252) have more difficulty quitting smoking compared to noncarriers (n=665), and whether age moderated this association. The genotype by age interaction was significant for 7-day point-prevalence abstinence rates (p=0.04) and time to 7-day failure (p=0.03). Among smokers over age 60, ε4 carriers were less likely to quit (OR=0.27, p=0.018) and relapsed more quickly (HR=3.38, p=0.001) compared to noncarriers. The genotype association with relapse was non-significant among younger smokers. An increased understanding of the underlying pathophysiological mechanisms of this association could facilitate the development of targeted therapies for smokers with increased risk for cognitive decline.
smoking; smoking cessation; relapse; nicotine; cognition; APOE
Survival data can contain an unknown fraction of subjects who are “cured” in the sense of not being at risk of failure. We describe such data with cure-mixture models, which separately model cure status and the hazard of failure among non-cured subjects. No diagnostic currently exists for evaluating the fit of such models; the popular Schoenfeld residual (Schoenfeld, 1982. Partial residuals for the proportional hazards regression-model. Biometrika
69, 239–241) is not applicable to data with cures. In this article, we propose a pseudo-residual, modeled on Schoenfeld's, to assess the fit of the survival regression in the non-cured fraction. Unlike Schoenfeld's approach, which tests the validity of the proportional hazards (PH) assumption, our method uses the full hazard and is thus also applicable to non-PH models. We derive the asymptotic distribution of the residuals and evaluate their performance by simulation in a range of parametric models. We apply our approach to data from a smoking cessation drug trial.
Accelerated failure time; Long-term survivors; Proportional hazards; Residual analysis
Smokers with a faster rate of nicotine metabolism, estimated using the ratio of 3′-hydroxycotinine (3-HC) to cotinine, have lower plasma nicotine levels and are more likely to relapse with 21 mg nicotine patch therapy, than smokers with slower rates of nicotine metabolism. Thus, faster metabolizers of nicotine may require a higher nicotine patch dose to achieve cessation.
This proof of concept randomized placebo-controlled trial evaluated the efficacy and safety of 8 weeks of 42 mg transdermal nicotine versus 21 mg, among 87 fast metabolizers of nicotine (3-HC/cotinine ≥ 0.18).
After 1 week of treatment, an intent-to-treat (ITT) analysis showed that participants treated with 42 mg nicotine had significantly higher expired-air carbon monoxide (CO)-confirmed 24-hr abstinence (75% vs. 58.1%; OR = 3.21; 95% CI: 1.12–9.24, p = .03) but not 7-day abstinence (50% vs. 34.9%; OR = 2.02; 95% CI: 0.82–4.94, p = .13). After 8 weeks of treatment, ITT analysis showed that participants treated with 42 mg nicotine had marginally higher rates of CO-confirmed 24-hr abstinence (45.5% vs. 30.2%; OR = 2.32; 95% CI: 0.92–5.92, p = .08) but not 7-day abstinence (29.6% vs. 23.3%; OR = 1.52, 95% CI: 0.57–4.07, p = .41). Percent nicotine and cotinine replacement were significantly greater for 42 mg nicotine versus 21 mg (p < .005). There were no significant differences between treatment arms in the frequency of severe side effects and serious adverse events or blood pressure during treatment (p > .10).
Further examination of the efficacy of 42 mg nicotine patch therapy for fast metabolizers of nicotine is warranted.
Online social networks represent a potential mechanism for the dissemination of health interventions including smoking cessation; however, which elements of an intervention determine diffusion between participants is unclear. Diffusion is frequently measured using R, the reproductive rate, which is determined by the duration of use (t), the ‘contagiousness’ of an intervention (β) and a participant's total contacts (z). We have developed a Facebook ‘app’ that allows us to enable or disable various components designed to impact the duration of use (expanded content, proactive contact), contagiousness (active and passive sharing) and number of contacts (use by non-smoker supporters). We hypothesised that these elements would be synergistic in their impact on R, while including non-smokers would induce a ‘carrier’ state allowing the app to bridge clusters of smokers.
Methods and analysis
This study is a fractional factorial, randomised control trial of the diffusion of a Facebook application for smoking cessation. Participants recruited through online advertising are randomised to 1 of 12 cells and serve as ‘seed’ users. All user interactions are tracked, including social interactions with friends. Individuals installing the application that can be traced back to a seed participant are deemed ‘descendants’ and form the outcome of interest. Analysis will be conducted using Poisson regression, with event count as the outcome and the number of seeds in the cell as the exposure.
The results will be reported as a baseline R0 for the reference group, and incidence rate ratio for the remainder of predictors.
Ethics and Dissemination
This study uses an abbreviated consent process designed to minimise barriers to adoption and was deemed to be minimal risk by the Institutional Review Board (IRB). Results will be disseminated through traditional academic literature as well as social media. If feasible, anonymised data and underlying source code are intended to be made available under an open source license.
ClinicalTrials.gov registration number
Internet; Smoking Cessation; Diffusion; Dissemination; RCT
Background and Objective
Photodynamic therapy (PDT) of thoracic malignancies involving the pleural surfaces is an active area of clinical investigation. The present report aims to characterize a model for PDT of disseminated non-small cell lung carcinoma grown orthotopically in nude mice, and to evaluate PDT effect on tumor and normal tissues.
H460 human non-small cell lung carcinoma (NSCLC) cells were injected percutaneously into the thoracic cavity of nude mice. HPPH-PDT (1 mg/kg, 24 h) was performed via the interstitial delivery (150 mW/cm) of 661 nm light to the thoracic cavity at fluences of 25-200 J/cm.
H460 tumors exhibited exponential growth within the thoracic cavity consisting of diffuse, gross nodular disease within 9 days after intrathoracic injection. Tumor volume, measured by magnetic resonance imaging (MRI), was highly correlated with the aggregate tumor mass extracted from the corresponding animal. Intrathoracic PDT at fluences of ≥ 50 J/cm produced significant decreases in tumor burden as compared to untreated controls, however mortality increased with rising fluence. Accordingly, 50 J/cm was selected for MRI studies to measure intra-animal PDT effects. Tumor distribution favored the ventral (vs. dorsal), caudal (vs. cranial), and right (vs. left) sides of the thoracic cavity by MRI; PDT did not change this spatial pattern despite an overall effect on tumor burden. Histopathology revealed edema and fibrin deposition within the pulmonary interstitium and alveoli of the PDT-treated thoracic cavity, as well as occasional evidence of vascular disruption. Prominent neutrophil infiltration with a concomitant decline in the lymphocyte compartment was also noted in the lung parenchyma within 24 hours after PDT.
HPPH-PDT of an orthotopic model of disseminated NSCLC is both feasible and effective using intracavitary light delivery. We establish this animal model, together with the treatment and monitoring approaches, as novel and valuable methods for the pre-clinical investigation of intrathoracic PDT of disseminated pleural malignancies.
HPPH; Photochlor®; 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a; interstitial illumination; magnetic resonance imaging; non-small cell lung carcinoma; photodynamic therapy; pleural malignancy
The perception that smoking relieves negative affect contributes to smoking persistence. Endogenous opioid neurotransmission, and the µ-opioid receptor (MOR) in particular, plays a role in affective regulation and is modulated by nicotine.
We examined the relationship of µ-opioid receptor binding availability in the amygdala to the motivation to smoke for negative affect relief and to the acute effects of smoking on affective responses.
Twenty-two smokers were scanned on two separate occasions after overnight abstinence using [11C]carfentanil positron emission tomography imaging: after smoking a nicotine-containing cigarette and after smoking a denicotinized cigarette. Self-reports of smoking motives were collected at baseline, and measures of positive and negative affect were collected pre- and post- cigarette smoking.
Higher MOR availability in the amygdala was associated with motivation to smoke to relieve negative affect. However, MOR availability was unrelated to changes in affect after smoking either cigarette.
Increased MOR availability in amygdala may underlie the motivation to smoke for negative affective relief. These results are consistent with previous data highlighting the role of µ-opioid receptor neurotransmission in smoking behavior.
Smoking motivation; µ-opioid receptor; amygdala; affect regulation
Galanin modulates dopaminergic neurotransmission in the mesolimbic dopamine system, thereby influencing the rewarding effects of nicotine. Variants in the galanin receptor 1 (GALR1) gene have been associated with retrospective craving severity and heaviness of smoking in prior research. We investigated pharmacogenetic associations of the previously studied GALR1 polymorphism, rs2717162, in 1217 smokers of European ancestry who participated in one of three pharmacogenetic smoking cessation clinical trials and were treated with nicotine patch (n=623), nicotine nasal spray (n=189), bupropion (n=213), or placebo (n=192). The primary endpoint was abstinence (7-day point prevalence, biochemically confirmed) at the end of treatment. Cravings to smoke were assessed on the target quit day (TQD). The longitudinal regression model revealed a significant genotype by treatment interaction (P=0.03). There was a reduced odds of quitting success with the presence of at least one minor (C) allele in the bupropion-treated group (OR=0.43; 95% CI=0.22–0.77; P=0.005) but equivalent quit rates by genotype in the nicotine-replacement therapy groups. This genotype by treatment interaction was reproduced in a Cox regression model of time to relapse (P=0.04). In the bupropion trial, smokers carrying the C allele also reported more severe TQD cravings. Further research to identify functional variants in GALR1 and to replicate pharmacogenetic associations is warranted.
nicotine; addiction; craving; pharmacogenetics; galanin receptor; behavioral science; neurogenetics; pharmacogenetics / pharmacogenomics; psychiatry & behavioral sciences; nicotine; addiction; craving; pharmacogenetics; galanin receptor 1
The efficacy of photodynamic therapy (PDT) depends upon the delivery of both photosensitizing drug and oxygen. In this study, we hypothesized that local vascular microenvironment is a determinant of tumor response to PDT. Tumor vascularization and its basement membrane (collagen) were studied as a function of supplementation with basement membrane matrix (Matrigel) at the time of tumor cell inoculation. Effects on vascular composition with consequences to tumor hypoxia, photosensitizer uptake and PDT response were measured. Matrigel-supplemented tumors developed more normalized vasculature, composed of smaller and more uniformly-spaced blood vessels than their unsupplemented counterparts, but these changes did not affect tumor oxygenation or PDT-mediated direct cytotoxicity. However, PDT-induced vascular damage increased in Matrigel-supplemented tumors, following an affinity of the photosensitizer Photofrin for collagen-containing vascular basement membrane coupled with increased collagen content in these tumors. The more highly-collagenated tumors demonstrated more vascular congestion and ischemia after PDT, along with a higher probability of curative outcome that was collagen dependent. In the presence of photosensitizer-collagen localization, PDT effects on collagen were evidenced by a decrease in its association with vessels. Together, our findings demonstrate that photosensitizer localization to collagen increases vascular damage and improves treatment efficacy in tumors with greater collagen content. The vascular basement membrane is thus identified to be a determinant of therapeutic outcome in PDT of tumors.
collagen; photodynamic therapy; microenvironment; normalization; vasculature
People who quit smoking often gain 11–12 pounds, on average, which can frequently lead to a relapse to smoking. This study evaluated whether extended vs. standard duration treatment with nicotine patch helps those able to quit smoking to reduce cessation-induced weight gain and explored nicotine patch adherence as a mediator of treatment effects.
Design and Setting
We examined data from a completed randomized placebo-controlled clinical trial of extended (24 weeks) vs. standard (8 weeks plus 16 weeks of placebo) transdermal nicotine patch therapy. Changes in measured weight over 24 weeks were compared across the two treatment arms, controlling for gender, baseline smoking rate, and previous weight. Adherence to patch use was assessed using self-report of daily use over 24 weeks.
139 clinical trial participants who were confirmed to be abstinent at weeks 8 and 24.
Compared to participants who received 8 weeks of nicotine patch therapy, participants who received 24 weeks of treatment showed significantly less weight gain from pre-treatment to week 24 (β = −4.76, 95% CI: −7.68 to −1.84, p = .002) and significantly less weight gain from week 8 to week 24 (β = −2.31, 95% CI: −4.39 to −0.23, p = .03). Extended treatment increased patch adherence which, in turn, reduced weight gain; patch adherence accounted for 20% of the effect of treatment arm on weight gain.
Compared to 8 weeks of transdermal nicotine therapy, 24 weeks of patch treatment may help to reduce the weight gain that is typical among smokers who are able to achieve abstinence from tobacco use. Extended treatment increased nicotine patch adherence which, in turn, reduced weight gain.
Smoking cessation is a process that unfolds over time and is characterized by intermittent lapses. Behavioral relapse prevention interventions commonly assume that lapse-relapse progression is driven by a set of psychological responses known as the Abstinence Violation Effect (AVE; Marlatt & Gordon, 1985), yet efforts to reduce the AVE have generally failed to affect clinical outcomes. We used parametric recurrent event survival analyses to better understand the dynamic relationship between a set of AVE responses to lapsing and subsequent lapse-relapse progression. Participants were 203 smokers who achieved abstinence and subsequently lapsed on one or more separate occasions. Using electronic diaries for ecological momentary assessment, participants responded to items assessing three core components of the AVE (internal attribution of self-blame for the lapse, abstinence self-efficacy and guilt) following a total of 1,001 smoking episodes in near real time. Contrary to hypothesis, neither self-blame, self-efficacy nor guilt following participants’ first lapse predicted relapse, and all three were overshadowed by responses to recurrent lapses that followed. Controlling for responses to their first lapse, responses to each additional lapse did prospectively predict lapse progression, such that drops in self-efficacy were associated with accelerated progression to a subsequent lapse (HR=1.09, CI=1.02–1.15), while increases in internal attributions of blame actually protected against lapsing (HR=0.98, CI=0.97–0.99). Treatment with nicotine patches slowed recurrent lapse progression (HR=0.58, CI=0.48–0.70), but this effect dissipated over multiple lapses, and was moderated by elevated ratings of post-lapse guilt (HR=1.08, CI=1.01–1.18), which predicted accelerated progression within the active patch group, while protecting against lapse in the placebo group. Results highlight the dynamic nature of lapse responses during smoking cessation, indicating that self-efficacy predicts progression from one lapse to the next, while attributions of self-blame and guilt did not influence progression as predicted by the RPM.
Smoking; lapse; relapse; abstinence violation effect
Smoking cessation trials generally record information on daily smoking behavior, but base analyses on measures of smoking status at the end of treatment (EOT). We present an alternative approach that analyzes the entire sequence of daily smoking status observations.
We analyzed daily abstinence data from a smoking cessation trial, using two longitudinal logistic regression methods: A mixed-effects (ME) model and a generalized estimating equations (GEE) model. We compared results to a standard analysis that takes as outcome abstinence status at EOT. We evaluated time-varying covariates (smoking history and time-varying drug effect) in the longitudinal analysis and compared ME and GEE approaches.
We observed some differences in the estimated treatment effect odds ratios across models, with narrower confidence intervals under the longitudinal models. GEE yields similar results to ME when only baseline factors appear in the model, but gives biased results when one includes time-varying covariates. The longitudinal models indicate that the quit probability declines and the drug effect varies over time. Both the previous day’s smoking status and recent smoking history predict quit probability, independently of the drug effect.
When analysing outcomes of studies from smoking cessation interventions, longitudinal models with multiple outcome data points, rather than just end of treatment, can makes efficient use of the data and incorporate time-varying covariates. The generalized estimating equations approach should be avoided when using time-varying predictors.
Generalized estimating equations; longitudinal analysis; mixed-effects model
Genome-wide association studies have linked single-nucleotide polymorphisms (SNPs) in the CHRNA5/A3/B4 gene cluster with heaviness of smoking. The nicotine metabolite ratio (NMR), a measure of the rate of nicotine metabolism, is associated with the number of cigarettes per day (CPD) and likelihood of cessation. We tested the potential interacting effects of these two risk factors on CPD.
Pretreatment data from three prior clinical trials were pooled for analysis. One thousand and thirty treatment seekers of European ancestry with genotype data for the CHRNA5/A3/B4 SNPs rs578776 and rs1051730 and complete data for NMR and CPD at pretreatment were included. Data for the third SNP, rs16969968, were available for 677 individuals. Linear regression models estimated the main and interacting effects of genotype and NMR on CPD.
We confirmed independent associations between the NMR and CPD as well as between the SNPs rs16969968 and rs1051730 and CPD. We did not detect a significant interaction between NMR and any of the SNPs examined.
This study demonstrates the additive and independent association of the NMR and SNPs in the CHRNA5/A3/B4 gene cluster with smoking rate in treatment-seeking smokers.
To evaluate the novel nanoparticle reconstituted bacteriochlorin e6 bisoleate low-density lipoprotein (r-Bchl-BOA-LDL) for its efficacy as a photodynamic therapy agent delivery system in xenografts of human hepatoblastoma G2 (HepG2) tumors.
Materials & methods
Bchl-BOA was encapsulated in the nanoparticle low-density lipoprotein (LDL), a native particle whose receptor’s overexpression is a cancer signature for a number of neoplasms. Evaluation of r-Bchl-BOA-LDL as a potential photosensitizer was performed using a tumor response and foot response assay.
Results & discussion
When compared with controls, tumor regrowth was significantly delayed at injected murine doses of 2 µmole/kg r-Bchl-BOA-LDL after illumination at fluences of 125, 150 or 175 J/cm2. Foot response assays showed that although normal tissue toxicity accompanied the higher fluences it was significantly reduced at the lowest fluence tested.
This research demonstrates that r-Bchl-BOA-LDL is an effective photosensitizer and a promising candidate for further investigation.
bacteriochlorophyll; low-density lipoprotein; nanoparticle; photodynamic therapy; xenograft hepatoma
Photodynamic therapy (PDT) with low light fluence rate has rarely been studied in protocols that use short drug–light intervals and thus deliver illumination while plasma concentrations of photosensitizer are high, creating a prominent vascular response. In this study, the effects of light fluence rate on PDT response were investigated using motexafin lutetium (10 mg/kg) in combination with 730 nm light and a 180-min drug–light interval. At 180 min, the plasma level of photosensitizer was 5.7 ng/μl compared to 3.1 ng/mg in RIF tumor, and PDT-mediated vascular effects were confirmed by a spasmodic decrease in blood flow during illumination. Light delivery at 25 mW/cm2 significantly improved long-term tumor responses over that at 75 mW/cm2. This effect could not be attributed to oxygen conservation at low fluence rate, because 25 mW/cm2 PDT provided little benefit to tumor hemoglobin oxygen saturation. However, 25 mW/cm2 PDT did prolong the duration of ischemic insult during illumination and was correspondingly associated with greater decreases in perfusion immediately after PDT, followed by smaller increases in total hemoglobin concentration in the hours after PDT. Increases in blood volume suggest blood pooling from suboptimal vascular damage; thus the smaller increases after 25 mW/cm2 PDT provide evidence of more widespread vascular damage, which was accompanied by greater decreases in clonogenic survival. Further study of low fluence rate as a means to improve responses to PDT under conditions designed to predominantly damage vasculature is warranted.
Improving smoking intervention trial retention in underserved populations remains a public health priority. Low retention rates undermine clinical advancements that could reduce health disparities. To examine the effects of recruitment strategies on participant retention among 279 low-income, maternal smokers who initiated treatment in a 16-week behavioral counseling trial to reduce child secondhand smoke exposure (SHSe). Participants were recruited using either reactive strategies or methods that included proactive strategies. Logistic regression analysis was used to test associations among retention and recruitment method in the context of other psychosocial and sociodemographic factors known to relate to retention. Backwards stepwise procedures determined the most parsimonious solution. Ninety-four percent of participants recruited with proactive + reactive methods were retained through end of treatment compared to 74.7% of reactive-recruited participants. Retention likelihood was five times greater if participants were recruited with proactive + reactive strategies rather than reactive recruitment alone (odds ration [OR] = 5.36; confidence interval [CI], 2.31–12.45). Greater knowledge of SHS consequences (OR = 1.58; CI, 1.07–2.34) was another significant factor retained in the final LR model. Proactive recruitment may improve retention among underserved smokers in behavioral intervention trials. Identifying factors influencing retention may improve the success of recruitment strategies in future trials, in turn, enhancing the impact of smoking interventions.
Retention; Recruitment; Underserved; Secondhand smoke