1. Home
  2. risk

risk

Evaluating the Association Between Low-Density Lipoprotein Cholesterol Reduction and Relative and Absolute Effects of Statin Treatment A Systematic Review and Meta-analysis

Author/s: 
Byrne, P., Demasi, M., Jones, M., Smith, S. M., O'Brien, K. K., DuBroff, R.

Importance: The association between statin-induced reduction in low-density lipoprotein cholesterol (LDL-C) levels and the absolute risk reduction of individual, rather than composite, outcomes, such as all-cause mortality, myocardial infarction, or stroke, is unclear.

Objective: To assess the association between absolute reductions in LDL-C levels with treatment with statin therapy and all-cause mortality, myocardial infarction, and stroke to facilitate shared decision-making between clinicians and patients and inform clinical guidelines and policy.

Data sources: PubMed and Embase were searched to identify eligible trials from January 1987 to June 2021.

Study selection: Large randomized clinical trials that examined the effectiveness of statins in reducing total mortality and cardiovascular outcomes with a planned duration of 2 or more years and that reported absolute changes in LDL-C levels. Interventions were treatment with statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) vs placebo or usual care. Participants were men and women older than 18 years.

Data extraction and synthesis: Three independent reviewers extracted data and/or assessed the methodological quality and certainty of the evidence using the risk of bias 2 tool and Grading of Recommendations, Assessment, Development and Evaluation. Any differences in opinion were resolved by consensus. Meta-analyses and a meta-regression were undertaken.

Main outcomes and measures: Primary outcome: all-cause mortality. Secondary outcomes: myocardial infarction, stroke.

Findings: Twenty-one trials were included in the analysis. Meta-analyses showed reductions in the absolute risk of 0.8% (95% CI, 0.4%-1.2%) for all-cause mortality, 1.3% (95% CI, 0.9%-1.7%) for myocardial infarction, and 0.4% (95% CI, 0.2%-0.6%) for stroke in those randomized to treatment with statins, with associated relative risk reductions of 9% (95% CI, 5%-14%), 29% (95% CI, 22%-34%), and 14% (95% CI, 5%-22%) respectively. A meta-regression exploring the potential mediating association of the magnitude of statin-induced LDL-C reduction with outcomes was inconclusive.

Conclusions and relevance: The results of this meta-analysis suggest that the absolute risk reductions of treatment with statins in terms of all-cause mortality, myocardial infarction, and stroke are modest compared with the relative risk reductions, and the presence of significant heterogeneity reduces the certainty of the evidence. A conclusive association between absolute reductions in LDL-C levels and individual clinical outcomes was not established, and these findings underscore the importance of discussing absolute risk reductions when making informed clinical decisions with individual patients.

Keywords 
cholesterol Statin Treatment meta-analysis LDL

Living Systematic Review on Cannabis and Other Plant-Based Treatments for Chronic Pain

Author/s: 
McDonagh, M. S., Wagner, J., Ahmed, A. Y., Morasco, B., Kansagara, D., Chou, R.

Objectives. To evaluate the evidence on benefits and harms of cannabinoids and similar plant-based compounds to treat chronic pain.

Data sources. Ovid® MEDLINE®, PsycINFO®, Embase®, the Cochrane Library, and SCOPUS® databases, reference lists of included studies, submissions received after Federal Register request were searched to July 2021.

Review methods. Using dual review, we screened search results for randomized controlled trials (RCTs) and observational studies of patients with chronic pain evaluating cannabis, kratom, and similar compounds with any comparison group and at least 1 month of treatment or followup. Dual review was used to abstract study data, assess study-level risk of bias, and rate the strength of evidence. Prioritized outcomes included pain, overall function, and adverse events. We grouped studies that assessed tetrahydrocannabinol (THC) and/or cannabidiol (CBD) based on their THC to CBD ratio and categorized them as high-THC to CBD ratio, comparable THC to CBD ratio, and low-THC to CBD ratio. We also grouped studies by whether the product was a whole-plant product (cannabis), cannabinoids extracted or purified from a whole plant, or synthetic. We conducted meta-analyses using the profile likelihood random effects model and assessed between-study heterogeneity using Cochran’s Q statistic chi square and the I2 test for inconsistency. Magnitude of benefit was categorized into no effect or small, moderate, and large effects.

Results. From 2,850 abstracts, 20 RCTs (N=1,776) and 7 observational studies (N=13,095) assessing different cannabinoids were included; none of kratom. Studies were primarily short term, and 75 percent enrolled patients with a variety of neuropathic pain. Comparators were primarily placebo or usual care. The strength of evidence (SOE) was low, unless otherwise noted. Compared with placebo, comparable THC to CBD ratio oral spray was associated with a small benefit in change in pain severity (7 RCTs, N=632, 0 to10 scale, mean difference [MD] −0.54, 95% confidence interval [CI] −0.95 to −0.19, I2=28%; SOE: moderate) and overall function (6 RCTs, N=616, 0 to 10 scale, MD −0.42, 95% CI −0.73 to −0.16, I2=24%). There was no effect on study withdrawals due to adverse events. There was a large increased risk of dizziness and sedation and a moderate increased risk of nausea (dizziness: 6 RCTs, N=866, 30% vs. 8%, relative risk [RR] 3.57, 95% CI 2.42 to 5.60, I2=0%; sedation: 6 RCTs, N=866, 22% vs. 16%, RR 5.04, 95% CI 2.10 to 11.89, I2=0%; and nausea: 6 RCTs, N=866, 13% vs. 7.5%, RR 1.79, 95% CI 1.20 to 2.78, I2=0%). Synthetic products with high-THC to CBD ratios were associated with a moderate improvement in pain severity, a moderate increase in sedation, and a large increase in nausea (pain: 6 RCTs, N=390 to 10 scale, MD −1.15, 95% CI −1.99 to −0.54, I2=39%; sedation: 3 RCTs, N=335, 19% vs. 10%, RR 1.73, 95% CI 1.03 to 4.63, I2=0%; nausea: 2 RCTs, N=302, 12% vs. 6%, RR 2.19, 95% CI 0.77 to 5.39; I²=0%). We found moderate SOE for a large increased risk of dizziness (2 RCTs, 32% vs. 11%, RR 2.74, 95% CI 1.47 to 6.86, I2=0%). Extracted whole-plant products with high-THC to CBD ratios (oral) were associated with a large increased risk of study withdrawal due to adverse events (1 RCT, 13.9% vs. 5.7%, RR 3.12, 95% CI 1.54 to 6.33) and dizziness (1 RCT, 62.2% vs. 7.5%, RR 8.34, 95% CI 4.53 to 15.34). We observed a moderate improvement in pain severity when combining all studies of high-THC to CBD ratio (8 RCTs, N=684, MD −1.25, 95% CI −2.09 to −0.71, I2=50%; SOE: moderate). Evidence on whole-plant cannabis, topical CBD, low-THC to CBD, other cannabinoids, comparisons with active products, and impact on use of opioids was insufficient to draw conclusions. Other important harms (psychosis, cannabis use disorder, and cognitive effects) were not reported.

Conclusions. Low to moderate strength evidence suggests small to moderate improvements in pain (mostly neuropathic), and moderate to large increases in common adverse events (dizziness, sedation, nausea) and study withdrawal due to adverse events with high- and comparable THC to CBD ratio extracted cannabinoids and synthetic products in short-term treatment (1 to 6 months). Evidence for whole-plant cannabis, and other comparisons, outcomes, and PBCs were unavailable or insufficient to draw conclusions. Small sample sizes, lack of evidence for moderate and long-term use and other key outcomes, such as other adverse events and impact on use of opioids during treatment, indicate that more research is needed.

Midodrine for the Prevention of Vasovagal Syncope : A Randomized Clinical Trial

Author/s: 
Sheldon, R., Faris, P., Tang, A., Ayala-Paredes, F., Guzman, J., Marquez, M., Morillo, C. A., Krahn, A. D., Kus, T., Ritchie, D., Safdar, S., Maxey, C., Raj, S. R.

Background: Recurrent vasovagal syncope is common, responds poorly to treatment, and causes physical trauma and poor quality of life. Midodrine prevents hypotension and syncope during tilt tests in patients with vasovagal syncope.

Objective: To determine whether midodrine can prevent vasovagal syncope in usual clinical conditions.

Design: Randomized, double-blind, placebo-controlled clinical trial. (ClinicalTrials.gov: NCT01456481).

Setting: 25 university hospitals in Canada, the United States, Mexico, and the United Kingdom.

Patients: Patients with recurrent vasovagal syncope and no serious comorbid conditions.

Intervention: Patients were randomly assigned 1:1 to placebo or midodrine and followed for 12 months.

Measurements: The primary outcome measure was the proportion of patients with at least 1 syncope episode during follow-up.

Results: The study included 133 patients who had had a median of 6 syncope episodes in the prior year (median age, 32 years; 73% female). Compared with patients receiving placebo, fewer patients receiving midodrine had at least 1 syncope episode (28 of 66 [42%] vs. 41 of 67 [61%]). The relative risk was 0.69 (95% CI, 0.49 to 0.97; P = 0.035). The absolute risk reduction was 19 percentage points (CI, 2 to 36 percentage points), and the number needed to treat to prevent 1 patient from having syncope was 5.3 (CI, 2.8 to 47.6). The time to first syncope was longer with midodrine (hazard ratio, 0.59 [CI, 0.37 to 0.96]; P = 0.035; log-rank P = 0.031). Adverse effects were similar in both groups.

Limitation: Small study size, young and healthy patients, relatively short observation period, and high proportion of patients from 1 center.

Conclusion: Midodrine can reduce the recurrence of syncope in healthy, younger patients with a high syncope burden."

Keywords 
Midodrine Vasovagal Syncope clinical trial prevention treatment

Association of Statin Use With All-Cause and Cardiovascular Mortality in US Veterans 75 Years and Older

Author/s: 
Orkaby, A.R., Driver, J.A., Ho, Y., et al.

Importance: Data are limited regarding statin therapy for primary prevention of atherosclerotic cardiovascular disease (ASCVD) in adults 75 years and older.

Objective: To evaluate the role of statin use for mortality and primary prevention of ASCVD in veterans 75 years and older.

Design, setting, and participants: Retrospective cohort study that used Veterans Health Administration (VHA) data on adults 75 years and older, free of ASCVD, and with a clinical visit in 2002-2012. Follow-up continued through December 31, 2016. All data were linked to Medicare and Medicaid claims and pharmaceutical data. A new-user design was used, excluding those with any prior statin use. Cox proportional hazards models were fit to evaluate the association of statin use with outcomes. Analyses were conducted using propensity score overlap weighting to balance baseline characteristics.

Exposures: Any new statin prescription.

Main outcomes and measures: The primary outcomes were all-cause and cardiovascular mortality. Secondary outcomes included a composite of ASCVD events (myocardial infarction, ischemic stroke, and revascularization with coronary artery bypass graft surgery or percutaneous coronary intervention).

Results: Of 326 981 eligible veterans (mean [SD] age, 81.1 [4.1] years; 97% men; 91% white), 57 178 (17.5%) newly initiated statins during the study period. During a mean follow-up of 6.8 (SD, 3.9) years, a total 206 902 deaths occurred including 53 296 cardiovascular deaths, with 78.7 and 98.2 total deaths/1000 person-years among statin users and nonusers, respectively (weighted incidence rate difference [IRD]/1000 person-years, -19.5 [95% CI, -20.4 to -18.5]). There were 22.6 and 25.7 cardiovascular deaths per 1000 person-years among statin users and nonusers, respectively (weighted IRD/1000 person-years, -3.1 [95 CI, -3.6 to -2.6]). For the composite ASCVD outcome there were 123 379 events, with 66.3 and 70.4 events/1000 person-years among statin users and nonusers, respectively (weighted IRD/1000 person-years, -4.1 [95% CI, -5.1 to -3.0]). After propensity score overlap weighting was applied, the hazard ratio was 0.75 (95% CI, 0.74-0.76) for all-cause mortality, 0.80 (95% CI, 0.78-0.81) for cardiovascular mortality, and 0.92 (95% CI, 0.91-0.94) for a composite of ASCVD events when comparing statin users with nonusers.

Conclusions and relevance: Among US veterans 75 years and older and free of ASCVD at baseline, new statin use was significantly associated with a lower risk of all-cause and cardiovascular mortality. Further research, including from randomized clinical trials, is needed to more definitively determine the role of statin therapy in older adults for primary prevention of ASCVD.

Conflict of interest statement

Conflict of Interest Disclosures: Dr Djousse reported receiving grants from Merck. No other disclosures were reported.

Physical Distancing, Face Masks, and Eye Protection to Prevent Person-To-Person Transmission of SARS-CoV-2 and COVID-19: A Systematic Review and Meta-Analysis

Author/s: 
Chu, D.K., Akl, E.A., Duda, S., Solo, K., Yaacoub, S., Schünemann, H.J., COVID-19 Systematic Urgent Review Group Effort (SURGE) study authors

Abstract

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19 and is spread person-to-person through close contact. We aimed to investigate the effects of physical distance, face masks, and eye protection on virus transmission in health-care and non-health-care (eg, community) settings.

Methods: We did a systematic review and meta-analysis to investigate the optimum distance for avoiding person-to-person virus transmission and to assess the use of face masks and eye protection to prevent transmission of viruses. We obtained data for SARS-CoV-2 and the betacoronaviruses that cause severe acute respiratory syndrome, and Middle East respiratory syndrome from 21 standard WHO-specific and COVID-19-specific sources. We searched these data sources from database inception to May 3, 2020, with no restriction by language, for comparative studies and for contextual factors of acceptability, feasibility, resource use, and equity. We screened records, extracted data, and assessed risk of bias in duplicate. We did frequentist and Bayesian meta-analyses and random-effects meta-regressions. We rated the certainty of evidence according to Cochrane methods and the GRADE approach. This study is registered with PROSPERO, CRD42020177047.

Findings: Our search identified 172 observational studies across 16 countries and six continents, with no randomised controlled trials and 44 relevant comparative studies in health-care and non-health-care settings (n=25 697 patients). Transmission of viruses was lower with physical distancing of 1 m or more, compared with a distance of less than 1 m (n=10 736, pooled adjusted odds ratio [aOR] 0·18, 95% CI 0·09 to 0·38; risk difference [RD] -10·2%, 95% CI -11·5 to -7·5; moderate certainty); protection was increased as distance was lengthened (change in relative risk [RR] 2·02 per m; pinteraction=0·041; moderate certainty). Face mask use could result in a large reduction in risk of infection (n=2647; aOR 0·15, 95% CI 0·07 to 0·34, RD -14·3%, -15·9 to -10·7; low certainty), with stronger associations with N95 or similar respirators compared with disposable surgical masks or similar (eg, reusable 12-16-layer cotton masks; pinteraction=0·090; posterior probability >95%, low certainty). Eye protection also was associated with less infection (n=3713; aOR 0·22, 95% CI 0·12 to 0·39, RD -10·6%, 95% CI -12·5 to -7·7; low certainty). Unadjusted studies and subgroup and sensitivity analyses showed similar findings.

Interpretation: The findings of this systematic review and meta-analysis support physical distancing of 1 m or more and provide quantitative estimates for models and contact tracing to inform policy. Optimum use of face masks, respirators, and eye protection in public and health-care settings should be informed by these findings and contextual factors. Robust randomised trials are needed to better inform the evidence for these interventions, but this systematic appraisal of currently best available evidence might inform interim guidance.

Funding: World Health Organization.

Keywords 
face masks social distancing eye shields

Treatment of Depression in Children and Adolescents: A Systematic Review. Comparative Effectiveness Review No. 224

Author/s: 
Viswanathan, M, Kennedy, SM, McKeeman, J, Christian, R, Coker-Schwimmer, Cook Middleton, Bann, C, Lux, L, Randolph, Forman-Hoffman, V

Background. Depressive disorders can affect long-term mental and physical health functioning among children and adolescents, including increased risk of suicide. Despite access to several nonpharmacological, pharmacological, and combined treatment options for childhood depression, clinicians contend with sparse evidence and are concerned about harms associated with treatment.

Methods. We conducted a systematic review to evaluate the efficacy, comparative effectiveness, and moderators of benefits and harms of available nonpharmacological and pharmacological treatments for children and adolescents with a confirmed diagnosis of a depressive disorder (DD)—major depressive disorder (MDD), persistent depressive disorder (previously termed dysthymia) or DD not otherwise specified. We searched five databases and other sources for evidence available from inception to May 29, 2019, dually screened the results, and analyzed eligible studies.

Results. We included in our analyses data from 60 studies (94 articles) that met our review eligibility criteria. For adolescents (study participants’ ages range from 12 to 18 years) with MDD, cognitive behavioral therapy (CBT), fluoxetine, escitalopram, and combined fluoxetine and CBT may improve depressive symptoms (1 randomized controlled trial [RCT] each, n ranges from 212 to 311); whether the magnitude of improvement is clinically significant is unclear. Among adolescents or children with MDD, CBT plus medications (8–17 years) may be associated with lower rates of relapse (1 RCT [n = 121]). In the same population (6–17 years), selective serotonin reuptake inhibitors (SSRIs) may be associated with improved response (7 RCTs [n = 1,525]; risk difference [RD], 72/1,000 [95% confidence interval (CI), 2 to 24], I2 = 9%) and functional status (5 RCTs [n = 941]; standardized mean difference, 0.16 [95% CI, 0.03 to 0.29]; I2 = 0%). For adolescents or children with any DD (7–18 years), CBT or family therapy may be associated with improvements in symptoms, response, or functional status (1 RCT each, n ranges from 64 to 99). Among children with any DD (7–12 years), family-based interpersonal therapy may be associated with improved symptoms (1 RCT, n = 38). Psychotherapy trials did not report harms. SSRIs may be associated with a higher risk of serious adverse events among adolescents or children with MDD (7–18 years; 9 RCTs [n = 2,206]; RD, 20/1,000 [95% CI, 1 to 440]; I2, 4%) and with a higher risk of withdrawal due to adverse events among adolescents with MDD (12–18 years; 4 RCTs [n = 1,296], RD, 26/1,000 [95% CI, 6 to 45]; I2, 0%). Paroxetine (1 RCT [n = 180]) may be associated with a higher risk of suicidal ideation or behaviors among adolescents with MDD (12–18 years). Evidence was insufficient to judge the risk of suicidal ideation or behavior for other SSRIs for adolescents and children with MDD or other DD (7–18 years) (10 RCTs [n = 2,368]; relative risk, 1.14 [95% CI, 0.89 to 1.45]; I2, 8%). However, this report excluded data on inpatients and those without depressive disorders, whom the Food and Drug Administration included in finding an increased risk of suicidality for all antidepressants across all indications.

Conclusion. Efficacious treatments exist for adolescents with MDD. SSRIs may be associated with increased withdrawal and serious adverse events. No evidence on harms of psychotherapy were identified.

Keywords 
children adolescent child depression treatment cognitive behavioral therapy selective serotonin reuptake inhibitors

Final Update Summary: Abdominal Aortic Aneurysm: Screening

Author/s: 
U. S. Preventive Services Task Force

IMPORTANCE:

An abdominal aortic aneurysm (AAA) is typically defined as aortic enlargement with a diameter of 3.0 cm or larger. The prevalence of AAA has declined over the past 2 decades among screened men 65 years or older in various European countries. The current prevalence of AAA in the United States is unclear because of the low uptake of screening. Most AAAs are asymptomatic until they rupture. Although the risk for rupture varies greatly by aneurysm size, the associated risk for death with rupture is as high as 81%.

OBJECTIVE:

To update its 2014 recommendation, the USPSTF commissioned a review of the evidence on the effectiveness of 1-time and repeated screening for AAA, the associated harms of screening, and the benefits and harms of available treatments for small AAAs (3.0-5.4 cm in diameter) identified through screening.

POPULATION:

This recommendation applies to asymptomatic adults 50 years or older. However, the randomized trial evidence focuses almost entirely on men aged 65 to 75 years.

EVIDENCE ASSESSMENT:

Based on a review of the evidence, the USPSTF concludes with moderate certainty that screening for AAA in men aged 65 to 75 years who have ever smoked is of moderate net benefit. The USPSTF concludes with moderate certainty that screening for AAA in men aged 65 to 75 years who have never smoked is of small net benefit. The USPSTF concludes that the evidence is insufficient to determine the net benefit of screening for AAA in women aged 65 to 75 years who have ever smoked or have a family history of AAA. The USPSTF concludes with moderate certainty that the harms of screening for AAA in women aged 65 to 75 years who have never smoked and have no family history of AAA outweigh the benefits.

RECOMMENDATIONS:

The USPSTF recommends 1-time screening for AAA with ultrasonography in men aged 65 to 75 years who have ever smoked. (B recommendation) The USPSTF recommends that clinicians selectively offer screening for AAA with ultrasonography in men aged 65 to 75 years who have never smoked rather than routinely screening all men in this group. (C recommendation) The USPSTF recommends against routine screening for AAA with ultrasonography in women who have never smoked and have no family history of AAA. (D recommendation) The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for AAA with ultrasonography in women aged 65 to 75 years who have ever smoked or have a family history of AAA. (I statement).

Keywords 
abdominal aortic aneurysm recommendation AAA ultrasonography risk smoke

Association Between Acute Gastroenteritis and Continuous Use of Proton Pump Inhibitors During Winter Periods of Highest Circulation of Enteric Viruses

Author/s: 
Vilcu, AM, Sabatte, L, Blanchon, T, Souty, C, Maravic, M, Lemaitre, M, Steichen, O, Hanslik, T

IMPORTANCE:

An increased risk of acute bacterial enteric infections has been reported among patients receiving proton pump inhibitor (PPI) therapy. The risk of acute gastroenteritis (AGE) of viral origin associated with continuous PPI exposure has been less studied.

OBJECTIVE:

To investigate the association between continuous PPI therapy and AGE occurrence during winter epidemic periods when the circulation of enteric viruses is the highest.

DESIGN, SETTING, AND PARTICIPANTS:

A matched cohort study was performed using a prospectively collected drug dispensing database from a large panel of community pharmacies in continental France. All patients recorded in the database during the 2015 to 2016 winter season, with documented age, sex, and use of an identifiable regular panel pharmacy, were eligible for the study. Each patient exposed to continuous PPI therapy was matched to 3 unexposed patients, according to year of birth, sex, and identifiable regular panel pharmacy. Analyses were performed between January 2017 and December 2018.

EXPOSURE:

Continuous PPI use during the 2015 to 2016 AGE winter epidemic.

MAIN OUTCOMES AND MEASURES:

The occurrence of at least 1 AGE episode during the 2015 to 2016 AGE winter epidemic was the main outcome. Episodes of AGE were identified using a previously validated algorithm based on drug dispensing data. Relative risks of AGE were estimated using a multivariable log-binomial model adjusted for age, sex, and treatments for chronic conditions.

RESULTS:

There were 233 596 patients receiving PPI therapy (median [interquartile range] age, 71 [62-81] years; 55.8% female) and 626 887 matched patients not receiving PPI therapy (median [interquartile range] age, 70 [61-80] years; 56.3% female) included in the analyses. At least 1 AGE epidemic episode was identified in 3131 patients (1.3%) receiving PPI therapy and in 4327 patients (0.7%) not receiving PPI therapy. The adjusted relative risk of AGE for those receiving PPI therapy was 1.81 (95% CI, 1.72-1.90) for all ages considered, 1.66 (95% CI, 1.54-1.80) among those aged 45 to 64 years, 2.19 (95% CI, 1.98-2.42) among those aged 65 to 74 years, and 1.98 (95% CI, 1.82-2.15) among those aged 75 years and older.

CONCLUSIONS AND RELEVANCE:

Continuous PPI therapy was associated with an increased risk of developing AGE during periods of highest circulation of enteric viruses. These findings support the hypothesis that PPI use is associated with an increased risk of enteric viral infections.

Keywords 
proton pump inhibitor PPI Gastroenteritis Season

Mobile phone text messaging and app-based interventions for smoking cessation

Author/s: 
Whittaker, R, McRobbie, H, Bullen, C, Rodgers, A, Gu, Y, Dobson, R

Abstract

Background

Mobile phone‐based smoking cessation support (mCessation) offers the opportunity to provide behavioural support to those who cannot or do not want face‐to‐face support. In addition, mCessation can be automated and therefore provided affordably even in resource‐poor settings. This is an update of a Cochrane Review first published in 2006, and previously updated in 2009 and 2012.

Objectives

To determine whether mobile phone‐based smoking cessation interventions increase smoking cessation rates in people who smoke.

Search methods

For this update, we searched the Cochrane Tobacco Addiction Group's Specialised Register, along with clinicaltrials.gov and the ICTRP. The date of the most recent searches was 29 October 2018.

Selection criteria

Participants were smokers of any age. Eligible interventions were those testing any type of predominantly mobile phone‐based programme (such as text messages (or smartphone app) for smoking cessation. We included randomised controlled trials with smoking cessation outcomes reported at at least six‐month follow‐up.

Data collection and analysis

We used standard methodological procedures described in the Cochrane Handbook for Systematic Reviews of Interventions. We performed both study eligibility checks and data extraction in duplicate. We performed meta‐analyses of the most stringent measures of abstinence at six months' follow‐up or longer, using a Mantel‐Haenszel random‐effects method, pooling studies with similar interventions and similar comparators to calculate risk ratios (RR) and their corresponding 95% confidence intervals (CI). We conducted analyses including all randomised (with dropouts counted as still smoking) and complete cases only.

Main results

This review includes 26 studies (33,849 participants). Overall, we judged 13 studies to be at low risk of bias, three at high risk, and the remainder at unclear risk. Settings and recruitment procedures varied across studies, but most studies were conducted in high‐income countries. There was moderate‐certainty evidence, limited by inconsistency, that automated text messaging interventions were more effective than minimal smoking cessation support (RR 1.54, 95% CI 1.19 to 2.00; I2 = 71%; 13 studies, 14,133 participants). There was also moderate‐certainty evidence, limited by imprecision, that text messaging added to other smoking cessation interventions was more effective than the other smoking cessation interventions alone (RR 1.59, 95% CI 1.09 to 2.33; I2 = 0%, 4 studies, 997 participants). Two studies comparing text messaging with other smoking cessation interventions, and three studies comparing high‐ and low‐intensity messaging, did not show significant differences between groups (RR 0.92 95% CI 0.61 to 1.40; I2 = 27%; 2 studies, 2238 participants; and RR 1.00, 95% CI 0.95 to 1.06; I2 = 0%, 3 studies, 12,985 participants, respectively) but confidence intervals were wide in the former comparison. Five studies compared a smoking cessation smartphone app with lower‐intensity smoking cessation support (either a lower‐intensity app or non‐app minimal support). We pooled the evidence and deemed it to be of very low certainty due to inconsistency and serious imprecision. It provided no evidence that smartphone apps improved the likelihood of smoking cessation (RR 1.00, 95% CI 0.66 to 1.52; I2 = 59%; 5 studies, 3079 participants). Other smartphone apps tested differed from the apps included in the analysis, as two used contingency management and one combined text messaging with an app, and so we did not pool them. Using complete case data as opposed to using data from all participants randomised did not substantially alter the findings.

Authors' conclusions

There is moderate‐certainty evidence that automated text message‐based smoking cessation interventions result in greater quit rates than minimal smoking cessation support. There is moderate‐certainty evidence of the benefit of text messaging interventions in addition to other smoking cessation support in comparison with that smoking cessation support alone. The evidence comparing smartphone apps with less intensive support was of very low certainty, and more randomised controlled trials are needed to test these interventions.

Plain Language Summary

Can programmes delivered by mobile phones help people to stop smoking?

Background

Tobacco smoking is a leading cause of preventable death. Mobile phones can be used to support people who want to quit smoking. In this review, we have focused on programmes that use text messages or smartphone apps to do so.

Search date

We searched for published and unpublished studies in October 2018.

Study characteristics

We included 26 randomised controlled studies (involving over 33,000 people) that compared smoking quit rates in people who received text messages or smartphone apps to help them quit, with people who did not receive these programmes. We were interested in studies that measured smoking for six months or longer.

Key results

We found that text messaging programmes may be effective in supporting people to quit, increasing quit rates by 50% to 60%. This was the case when they were compared to minimal support or were tested as an addition to other forms of stop‐smoking support. There was not enough evidence to determine the effect of smartphone apps.

Quality and completeness of the evidence

Most of the studies were of high quality, although three studies had high drop out rates. We are moderately confident in the results of the text messaging interventions, but there were some issues with unexplained differences between study findings and for some comparisons there was not much data. We have low confidence in the results concerning smartphone apps, and more studies are needed in this field.

Keywords 
smoking cessation mobile phone tobacco tobacco use text message
Subscribe to risk