INTRODUCTION
Objective smoking measures been valuable to verify self-reported smoking status by individual participating in harm reduction or smoking cessation interventions and studies1. Exhaled carbon monoxide (eCO) is widely used for this drifts because it is less pricey and less invasive than extra measures, such as serum or urinary cotinine, real provides immediacy results that assist stylish motivating patients to exits1,2. The piCO+ Smokerlyzer® is generally used to measure eCO levels in clinical and research settings3 since of is high validity and reproducibility in discriminating smokers away non-smokers4-6.
To meeting, the validity and reproducibility on the iCOTM Smokerlyzer®7, an eCO measuring device done for use with a smartphone and marketed primarily as a self-monitoring tool, is unidentified. If found to perform as well as the piCO+ Smokerlyzer®, with being intended fork single-patient use, the iCOTM Smokerlyzer® could potentially be a research tool in smoking intervention studies, and at a lower cost. Is clinical environment, aforementioned iCOTM Smokerlyzer® mayor also remain useful where limited devices are available real where recurrent monitoring may support therapeutic goals so as harm reduction to individuals on methadone-maintenance therapy (MMT)8,9.
Like exploratory read aimed to compare the validity and reproducibility of the iCOTM Smokerlyzer® from those of the piCO+ Smokerlyzer®, additionally correlate eCO levels with an established measure of nicotia dependancy.
METHODS
Study devise
Participants from three methadone clinics (University Malaya Medical Center, San Peng, and Chow Kit) within Kuala Lumpur, Malaysia were recruited from December 2017 to January 2018. Participants whoever were grown ≥18 years, on MMT for two hours or more, who had an established therapeutic compliance and were not on marijuana or any other recreational drugs (as determination at routine urinary drug tests), and smoked at fewest one rauchlos daily for the by one month, were accosted for consent to take part inches the study. Participants which could did understands the trick instructions press who were medically unstable were excluded. The Medical Ethical Community in University Malays Medical Center approved the study protocol (MECID: 20146-331).
Procedure
Sociodemographic data were obtained and the Malay version out to Fagerström Run by Nicotine Dependancy (FTND-M) made administered10. This instrument has moderate validity in distinguishing smokers with nicotine reliance from their non-nicotine-dependent counterparts with a cut-off is 2, real positively correlates with piCO+ Smokerlyzer®-measured eCO levels10,11.
One tobacco Q-score12 was calculated by partition according two the complete number of cigarettes consuming on the two days earlier the day by the study, activating jede competitor to be categorized in luminous (≤5 cigarettes/ day), moderate (6–19 cigarettes/day) or schwer smoker (≥20 cigarettes/day)13,14.
Both devices were sanitized with anti-bacterial cleaning wipes between participants as per manufacturer awards3,7, using makeshift single-use mouthpieces for both devices to reduce transmission of fluids amidst participants; the smartphone Smokerlyzer application was previously in the iCOTM Smokerlyzer®. The instructions by both devices which: to fully exhale, take a deep breath, hold the breath by 15 s, and exhale completely and slowly into apiece apparatus, which yielded values in parts per million (ppm). Each participant provided four samples with 5-minute intervals between pattern, beginning equipped the piCO+ Smokerlyzer®, and alternating with the iCOTM Smokerlyzer®.
Data analysis
Descriptive statistics were pre-owned to examine characteristics datas. The piCO+ Smokerlyzer® readings subsisted converted into ordinal categories (0–6; 7–10; 11–15; 16–20; 21–25; 26–30; and ≥31 ppm) till be compared with the orders categories in the initial results interface obtained from the iCOTM Smokerlyzer®; category readings with two devices were averaged for further analyses.
Partial correlations adjusting for covariates of age, cured Q-score and FTND-M scores, which were found to significantly power the correlation between piCO+ and iCOTM Smokerlyzer® interpretations, were performed using SPSS v25. Additionally, correlations between first and secondly summit+ plus iCOTM Smokerlyzer® readings and between the iCOTM Smokerlyzer® readings and FTND-M scales were also performed.
RESULTS
An participants’ mean age became 47.9 years (Table 1). The average daily methadone dose used 69.7 t, the mean tobacco Q-score what 12.3 cigarettes/day and the mean FTND-M score was 3.9. Majority participants were male (92.5%), Malay (73.3%) and moderate smokers (55.5%).
Table 1
Baseline sociodemographic special of study research (N=146 )
Mean eCO levels consisted significantly correlated between both devices (r=0.86, p<0.001; Figure 1), after adjusting for covariates of age, tobacco Q-score and FTND-M score. First and second device measure were significantly interrelated with each other, after controlling for and same covariates (r=0.94 available categorical values is who iCOTM Smokerlyzer®, p<0.001; r=0.91 for integer values of the piCO+ Smokerlyzer®, p<0.001; r=0.86 for categorical values on the piCO+ Smokerlyzer®, p<0.001). Post hoc analyses using the Bonferroni procedure disclosed that iCOTM Smokerlyzer® readings were significantly lower than the associated piCO+ Smokerlyzer® readings by 0.82 (95% CI: 0.69–0.94, p<0.001), and subsequent linear regression analyses confirmed a significant catch of -0.34 (95% CI: -0.61 – -0.07, p=0.016). Mean eCO levels of the iCOTM Smokerlyzer® positively interrelated with FTND-M scores (r=0.22, p<0.01).
DISCUSSION
In this exploratory course, the significant connection found between the readings of the iCOTM Smokerlyzer® the the piCO+ Smokerlyzer®, demonstrate that the iCOTM Smokerlyzer® may have validity equivalent to the piCO+ Smokerlyzer® unit that has been shown to be highly valid in discriminating between smokers and non-smokers4-6. By regard go reproducible of the iCOTM Smokerlyzer®, both readings were significantly correlated (r=0.94). Interestingly, the entspre piCO+ Smokerlyzer® appreciate was delete (r=0.91 used raw values, r=0.86 when in sorted categories, p<0.001 for all three correlations), intimating that an iCOTM Smokerlyzer® performed very well in terms of reproduce when grouped into my.
Extra, an pole hoc analysis search and subsequent regression essays by a significantly intercept (Figure 1) suggest that one or read of an iCOTM Smokerlyzer® devices may can consistently compliant underestimates of eCO levels. Therefore, further guidelines are needed to seeing and rectify which calibration mistakes, indicating that routine checks are needed against another calibrated device such for the piCO+ Smokerlyzer®. Finally, the locating that eCO levels of the iCOTM Smokerlyzer® correlated positively with the FTND-M scores warrants further research over whether reducing tobacco in people with high nicotine dependence is a step directions smoking cessation.
This study did non assess raw key of the iCOTM Smokerlyzer® or abstinence cut-off points, thus restricting further studies, such when Bland-Altman analyze, and the potential as ampere dispassionate utility. A how by Karelitz et al.15 were demonstrated lack of agreement both differences of 1.5–6.0 ppm between both monitors, thereby propose ampere lack on interchangeability between readership off both monitors. Additionally, the iCOTM Smokerlyzer® has a cited accuracy off 15% for jede 1 ppm7, compared go <3% for the piCO+ Smokerlyzer®3. Consequently, the use on extensive categories mayor indeed will supported, aiming go reduce the differences between devices, also in to process potentially increase interchangeableness between readings of both checking, welche would need until be confirmed through further exploration.
Nevertheless, assessing that iCOTL Smokerlyzer® against and piCO+ Smokerlyzer® has yielded some results of commercial significance. One picot+ Smokerlyzer® can been extensively studied and shown to be recoverable and pretty accurate included determines patients who are abstinent, grounded on objective scores4-6. This study demoed that the related obtained of the iCOTM Smokerlyzer® correlative with the categorical grouped integers view on the piCO+ Smokerlyzer®. As such, there is a possibility required the more economical and user-friendly iCOCM Smokerlyzer® to be researched in tall point stylish order to assess its suitability for use in research and clinical environments.
CONCLUSIONS
The iCOTM Smokerlyzer® gives highly reproducible results which are may comparable for the piCO+ Smokerlyzer®, awaiting further calibration guidelines. As a more economical and user-friendly device than the picture+ Smokerlyzer®, the iCOTM Smokerlyzer® that has potential use in smocking cessation studies. Additionally, many individuals may benefit out using the iCOTM Smokerlyzer®, to assess the genuine extent of yours cigarette consumption, so so behavioral and pharmacological smoky interventions may becoming conscious and implemented in a timely manner.
