Do people stop smoking if their doctor advises them to? Cochrane review says sometimes and it IS worth the effort

This post was originally written by Matt Field for the Mental Elf website, you can find the original here. 

As previously discussed on the Mental Elf, the rates of tobacco smoking in most developed countries are falling, helped in part by high levels of taxation and bans on smoking in public places.

However, over 20% of adults in the UK continue to smoke, and this means that smoking is the greatest single cause of premature illness and death.  Therefore, anything that can be done to persuade smokers to quit is likely to have a major impact on public health.

General Practitioners and other health professionals could play an important role if they simply advised their patients to stop smoking as a precursor to prescribing medication, or referring them to local Stop Smoking services. In this Cochrane review, Stead et al. (2013) looked at whether advice from doctors could help their patients to quit smoking.

Methods

This paper is an update of previous Cochrane reviews on this topic. The authors identified randomised controlled trials that examined the influence of smoking cessation advice from a medical practitioner on abstinence from smoking at least 6 months later.

Having identified relevant papers, the authors pooled the data and asked:

• - Is advice from a doctor to give up smoking more effective than no advice, in terms of the number of patients who manage to quit?
• 
  
• - Are there any benefits of offering more intensive advice (as opposed to just giving brief advice), and of following patients up afterwards?
• 
  

Results

Brief advice and intensive advice both improve quit rates, but only everso slightly

The total sample size was over 31,000, from 42 randomised trials that were published between 1972 and 2012.

The majority of the individual trials randomly assigned people to receive brief advice to give up smoking, or they got no advice at all (not even a wagging of the finger). There was enormous variation in what constituted ‘brief advice’, but this didn’t seem to affect the overall results too much.

There were 17 trials in which the intervention was classed as minimally intensive ‘brief advice’, and 11 trials in which the intervention was classed as more intensive.

• Comparison of minimally intensive brief advice with no advice demonstrated that brief advice led to a small but significant increase in quit rates (Relative Risk (RR) = 1.66, 95% CI 1.42 to 1.94).
• 
  
• Comparisons of more intensive advice with no advice also demonstrated an increase in quit rates (RR = 1.84; 95% CI 1.60 to 2.13).
• 
  
• However, this indirect comparison between different studies revealed no statistically significant difference between brief advice and more intensive advice (note the overlapping confidence intervals).
• 
  

There were fifteen additional trials that made a direct comparison between intensive advice and brief advice. This revealed significantly higher quit rates among people who received intensive advice compared to those who received only brief advice (RR = 1.37, 95% CI 1.20 to 1.56).

Other findings included a small incremental effect on quit rates if follow-ups were provided after the initial advice. However, provision of additional aids (such as self-help manuals) did not make much difference, and there were minimal differences between different types of intervention.

Discussion

Giving smokers brief advice to help them quit is better than nothing, but only just! However, it’s cheap and easy so definitely something that GPs should be doing.

Overall, patients who receive brief advice to quit smoking from their doctor are more likely to actually do so, compared to patients who receive no advice. The effect size is small, although it is slightly larger if the advice is more intensive, or if patients are followed up a bit later.

Can brief advice make a difference in the real world? The ‘unassisted quit rate’ (the percentage of smokers who will quit if given no help or advice whatsoever) is difficult to estimate, and it varied enormously between studies in this analysis. But a plausible estimate is 3%, and this gives us a ‘number needed to treat for an additional beneficial outcome’ (NNTB) ranging between 33 and 80. In other words, doctors would need to offer brief advice to between 33 and 80 of their patients in order to get one of them to stop smoking! While this may seem rather pitiful, we have to remember that most smokers do not manage to quit by themselves and anything that nudges smokers towards quitting, particularly something very quick and easy like brief advice from a doctor, should be put into practice whenever possible.  

The authors conclude their paper by stating that:

"Every smoker who does not receive advice represents a missed opportunity".

And the Mental Elf agrees with that!

Links

Stead LF, Buitrago D, Preciado N, Sanchez G, Hartmann-Boyce J, Lancaster T. Physician advice for smoking cessation. Cochrane Database of Systematic Reviews 2013, Issue 5. Art. No.: CD000165. DOI: 10.1002/14651858.CD000165.pub4.

Cochrane summary of this review

Research roundup summer 2013

This is the Summer 2013 research roundup from the Addiction Research Group based in the Department of Psychological Sciences, University of Liverpool. We have been hard at work throughout the ‘heatwave’ and (more typical) downpours of our British summer.  The fruits of our labours can be seen below...

Top spot goes to Gordon Fernie (a former post-doc) and colleagues who published a study in Addiction (Open Access) which looked at bidirectional relationships between three measures of behavioural impulsivity (delay discounting, risk-taking, and disinhibition) and alcohol involvement among adolescents. They measured impulsivity and alcohol involvement in 287 adolescents at five time points over the course of two years. The results show that individual differences in performance on three measures of behavioural impulsivity each predicted alcohol involvement six months later. However, alcohol involvement did not predict subsequent impulsivity. This study is the first to show that those three measures of impulsivity predict alcohol involvement after fairly short follow-up periods of six months. This press release generated a bit of media coverage, some of which can be seen here.

Andy Jones worked with Andrej Stancak on a study that was published in the Journal of Psychopharmacology, examining electrophysiological markers of response conflict during disinhibition and their relationship with alcohol consumption.  They demonstrated that when individuals performed a stop signal task (a measure of inhibitory control), the magnitude of the P300 component of the event-related potential during inhibition was inversely correlated with increased alcohol consumption during a subsequent laboratory taste test. This suggests that better inhibition (as inferred from brain activity during a task that requires inhibitory control) is associated with reduced consumption of alcohol.  This was the first study to directly examine the relationship between electrophysiological markers of inhibitory control, and alcohol-seeking.

Matt Field organised and edited a special issue on Addiction for The Journal of Experimental Psychopathology. The issue covered some of the current 'hot topics' in addictive behaviours including social influences, negative affect, motivated attention, implicit cognitive processes and disinhibition. Our research group contributed two papers for the special issue. We collaborated with colleagues from the Netherlands on a paper examining motivated attention (again using electrophysiological measures) in alcohol-dependent patients seeking treatment. Andy Jones and other colleagues at Liverpool also published a research paper that explored the effects of alcohol-related cues and contexts on disinhibited behaviour, a study that was conducted in our Bar Lab.

We contributed two review papers for a forthcoming special issue of CNS Spectrums. The first discusses the clinical relevance of attentional bias in substance use disorders and the second discusses pharmacological modulation of these biases. Staying on the topic of attentional bias, Matt Field wrote a critical commentary of a paper published in the journal European Addiction Research. You can find this, and other commentaries here. 

In other news…

We are delighted to welcome Dr Charlotte Hardman to our research group. An appetite and obesity researcher by trade, Charlotte has been working closely with the addiction group on projects related to food addiction and attentional bias to rewarding cues.

The addiction research group has expanded... for the summer at least! We are pleased to welcome a group of summer students who are working on research projects in addiction and motivated behaviour:

Marianne Erskine-Shaw, under the supervision of Abi Rose is working on a project examining alcohol intoxication and attentional bias. Her studentship was funded by the British Psychological Society. Jade Scott is working with Charlotte Hardman on attentional bias to food and alcohol cues, and Rebecca Dallas is working with Eric Robinson on a project examining the effects of peer influences on drinking behaviours in our Bar Lab. Both Jade and Rebecca are funded by the School of Psychology, University of Liverpool. 

Our research group played a (small) part in a successful application for funding from the National Institute for Health Research, details here. The broad aim of the funding is to investigate how to improve mental health care, and our group will be looking at interventions to reduce problem drinking. 

Paul Christiansen also received a grant from Alcohol Research UK to investigate beliefs about the acute effects of alcohol on impaired control over drinking, both in the laboratory and normal day-to day life. More on this later....

Finally, we have been getting out and about to disseminate our research! Matt Field, Pawel Jedras, Andy Jones and Paul Christiansen all attended the British Association for Psychopharmacology summer meeting in Harrogate. Pawel, Andy and Paul all gave a poster presentation on some of their current projects. Pawel also gave a short oral presentation in a symposium on reward and choice.  You can spot us talking shop in some pictures from the conference at the BAP’s facebook page. Some of Abi Rose's data was presented at the World Congress of World Congress of Behavioural and Cognitive Therapies (WCBCT) meeting in Lima, Peru in July. Slightly more exotic than Harrogate. 

That's it! If you are based in Liverpool and are interested in taking part in some of our research, you can email Andy Jones for information about studies that are running at the moment.

How Tequila Date

This brilliantly titled blog was written by Natasha Clarke for her own blog. You can read the original (and leave praise) here:

 http://tash13579.wordpress.com/2013/07/21/howtequiladate/

So, for the past few months I have been dissertation writing and it’s been the first summer in years where I have had to do work.  This has meant that, in stark contrast to last year where I was knee deep in mud at festivals, or sipping on mint tea in the Moroccan heat, I have been stuck in the library day in day out staring at a computer screen.

It has also meant that I have begun quite a serious love/hate relationship with evening television. For those of you in a similarly sad predicament you may have noticed Channel 4 has been putting on a “Mating Season”, my particular favourite programme being “First Dates”. A show that is pretty much what it says on the tin, an insight into the dating woes of desperately single individuals, involving a restaurant specifically used for first dates. It’s been funny, it’s been awkward, and at times l’ve had to look away. The dates I’ve found hardest to watch are those involving alcohol, where sentences become slurred, eyes become heavy and things are said that wouldn’t usually be said. For those of you who haven’t had the pleasure of watching any of these delightful moments, here is a little taster of Carl and Amanda’s very unsuccessful first date:

Now, I’m sure we have all been there, a few too many nerves = Dutch courage = disastrous date. Fortunately most of us who accidently have a little too much and want to forget the moment ever happened don’t have to watch the cringey moment back on television. But it did get me thinking: why (for many of us) is alcohol such an important part of these initial encounters? Is sober dating possible? And, does the amount you drink carve the way for the rest of your relationship?

When watching Carl and Amanda’s date back, it is clear he was out to get drunk, yet she politely turns back more drink and watches on amused as he continues. Would things have been different if she’d kept up? I know in the past I’ve tried to keep up with male friends, and slowly women have been closing the gender gap with alcohol consumption. This is worrying, as despite the equal roles we have in today’s society there are physiological differences that we cannot ignore, which make women more vulnerable to alcohol’s effects. For example women achieve higher blood alcohol concentrations (BACs) in less time than men, and have a greater risk of alcohol-related damage to the liver, heart and brain. Important reasons for a woman not to attempt to keep up with her slurring dating partner. But should we ignore these facts for the sake of love? After all, surely a man wants his woman  to be able to keep up? Apparently not. A study by LaBrie and colleagues in the US found that female students overestimate how much males want their female friends, dates and sexual partners to drink, and that this overestimation leads to a higher drinking level in a woman. So we drink more because we think that’s what men want, but men actually want us to drink less. What a health damaging misunderstanding.

Although the embarrassing sinking feeling the next morning might be enough to encourage a more toned down approach to the next date, on an even more sobering note are the serious risks involved with a higher consumption of alcohol in these dating situations. Alcohol contributes significantly to situations involving risky and sexual behaviour. A recent study in the US found that a shocking 25% of students reported one occurrence of alcohol-related regretted sex in the past month, and women were more likely to report this. When participants were asked about these encounters, increased drinking was linked to the belief that the alcohol would give “liquid courage”. A review byRehm and colleagues found that an increase of 0.1 mg/ml of BAC led to a 2.9% increase in the likelihood that an individual would engage in unsafe sex, leading to a higher risk for the transmission of STIs and unplanned pregnancies. Showing there may be a danger of ending up with more than you bargained for after an alcohol-fuelled date.

However, if the first date hurdle is passed without a nasty STI, and a couple move on to a second date and eventually end up an item, then what role does drinking play? As one might expect, it has been found that heavier levels of drinking are associated with decreased intimacy and increased relationship problems. However, with lower levels of alcohol use there were beneficial outcomes, such as positive effects on intimacy and partner behaviours, reinforcing the stressed importance of alcohol in moderation. This study also reported that alcohol consumption is not always harmful to relationships, as long as partners are drinking similar amounts, and are drinking together. This shows that if alcohol is going to be the third member of your relationship, it is important that you both enjoy it equally. Personally, I think a bottle of wine shared with your partner is fine, until you get more attached to the wine than your other half.

So it is clear that alcohol is an important element of the dating scene, and is used to engender courage in these nerve-wracking situations. But, research is demonstrating that too much is definitely going to be detrimental in a singletons search for love (not to mention embarrassing when you are on a TV show), and that once you are in a relationship, heavy drinking could result in a broken heart and an application for the show. For those of you who are interested in the world of sober dating, what I did find in my hunt for answers was a dating site specifically for daters who want to stay sober, so apparently it is possible. I can’t say I’ve joined just yet…

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Preventing alcohol misuse in teens with a personality-targeted intervention

This article was written by Inge Kersbergen. Inge is currently working on her Masters at Radboud University Nijmegen (Netherlands), and she will soon be starting a PhD at the University of Liverpool.

When I was in secondary school, we received a yearly questionnaire (the SchoolVragenLijst) that measured school-related attitudes and mental well-being (e.g., anxiety, problem behaviour). Based on the test scores, a few students (about 15 a year) were invited to a CBT based self-esteem class given by regular teachers, in which they were taught new coping skills and received new tools to handle challenges. This was thought to increase their school performance and their overall well-being.

The reason I’m telling you this, is because a recent study showed that a similar intervention reduced alcohol use and risky drinking behaviour in adolescents. Unlike other prevention programs, this intervention does not target attitudes towards alcohol. In fact, alcohol and drug use are only a minor focus of the intervention. The main focus of the intervention is providing teens with tools and strategies to counteract four different 'risk profiles' that are related to alcohol misuse (impulsivity, sensation seeking, hopelessness, and anxiety sensitivity). Providing them with these tools is thought to reduce their need to drink alcohol to cope, and so we would expect to see reductions in their alcohol consumption and problem drinking behaviour.

The researchers tested this hypothesis in a randomized controlled trial with 2633 students recruited from 21 secondary schools in London, who had an average age of 13.7 years. The Substance Use Risk Profile Scale was used to identify high risk teens in those schools. This questionnaire taps into the four risk profiles mentioned before. High risk teens in the test schools were offered a short intervention specific for their risk profile. In control schools, teens received drug education as usual. The four different interventions were based on Cognitive Behavioural Therapy (CBT) and Motivational Enhancement Therapy (MET) principles and were given in two 90-minute sessions that were led by trained school staff. Interventions specifically targeted personality traits belonging to each of the risk profiles. Each of the interventions provided information on the personality trait in question and its associated risky coping behaviour, such as interpersonal dependence, avoidance, aggression, and substance misuse. The students were encouraged to identify and challenge cognitive distortions that were specific to their personality profile and could lead to specific adverse behaviours (for instance, aggression in the case of impulsivity). Every six months for two years after the intervention, the researchers asked all of the students (including the ones that did not receive the intervention) whether or not they drank alcohol and if so, how much. Additionally, they measured the frequency of binge drinking and the severity of alcohol problems.

Results showed that the intervention was successful in a few different ways. Students in intervention schools were 29% less likely to drink alcohol than students in the control schools, regardless of risk status. Additionally, high risk teens in intervention schools were 43% less likely to engage in binge drinking and 29% less likely to report problem drinking behaviour than the high risk teens in control schools.

This intervention, therefore, seems to be a good way to prevent adolescent alcohol use and misuse. Not only did it have a positive influence on the high risk students’ drinking habits, but it also decreased the odds of drinking for low-risk students who did not receive the intervention, so long as other students in their school did ('herd effects'). Besides alcohol use, one could think of additional benefits. Providing high risk teens with coping tools may not only decrease their alcohol use, it might decrease risky behaviour in general (such as substance use, unprotected sex, etc.). With a little more information on why this intervention works and whether and how it could improve well-being in other domains, it has a strong potential for becoming a part of general education. If my school was able to arrange a yearly self-esteem course of ten sessions, other schools could certainly implement this two-session intervention in their curriculum.

Article of interest: Conrod, P.J., O’Leary-Barrett, M., Newton, N., Topper, L., Castellanos-Ryan, N., Mackie, C., & Girard, A. (2013). Effectiveness of a Selective, Personality-Targeted Prevention Program for Adolescent Alcohol Use and Misuse. A Cluster Randomized Controlled Trial. JAMA Psychiaty, 70(3), 334-342.

New Cochrane review finds that NRT, bupropion and varenicline are effective treatments for smoking cessation

This article was written by Andy Jones and Paul Christiansen for the Mental Elf website, you can find the original version of the article here.

Smoking is the main preventable cause of premature illness and death worldwide. Approximately 20% of deaths in men and 5% in woman over 30 can be attributed to smoking. The World Health Organization (WHO) estimates that 6 million people die from smoking related disease each year, with tobacco being the number one risk factor for non-communicable disease deaths. Indeed, the WHO views reducing tobacco use as a priority with today’s World No Tobacco Day campaigning for a ban on tobacco advertising to reduce uptake of smoking.

But what of those people already addicted to tobacco? Quitting smoking can significantly improve health and wellbeing; unfortunately, many smokers find it difficult to achieve permanent abstinence without support.

There are lots of treatments available for people who want to stop smoking

A number of drug treatments are available to help people to quit smoking.  The three most widely used types of treatment are; nicotine replacement therapies (NRT), bupropion (an antidepressant) and varenicline (a nicotine receptor partial agonist), all of which are licensed for use in Europe and the United States. Bupropion and varenicline are available on prescription, whist NRTs such as patches and gums are also available over the counter.

Treatments such as cytisine have also been used in other countries as a potential intervention, but are not yet widely available. Other therapies such as anxiolytics, selective serotonin reuptake inhibitors (SSRI’s), monoamine oxidase inhibitors (MAOI’s), opioid agonists, clonidine, mecamylamine (both originally marketed to lower blood pressure) and a cannabinoid agonist have also been trialed as potential pharmacological treatments.

The efficacy and safety of these treatments for smoking cessation is the focus of a new Cochrane systematic review published today (Cahill et al, 2013). The authors’ primary objectives were to examine how the most widely used pharmacotherapies compare with placebo, and each other, in achieving abstinence. Other less used treatments were also considered where possible. Secondly, comparisons between the benefits and risks of each treatment were conducted.

Methods

The authors conducted a meta-analysis on 12 Cochrane reviews between 2008 and 2012, investigating a total of 26 pharmacotherapies. The analysis consisted of 267 randomised control trials (RCTs) including over 101,000 smokers. Eligible trials had to include a comparable placebo condition, other active pharmacological treatments or a combination of both. The primary outcome was smoking cessation, for 6 months or longer from the start of treatment.

To compare the benefits with the risk of harm the authors looked at any adverse or serious adverse (life-threatening) events, which could have been attributed to the treatment. Adverse events included such things as nausea and insomnia. Serious adverse events included the onset of psychological disorders (such as depression and anxiety), suicidal idealization, neurological events (seizures) or cardiovascular problems.

Results

Using odds ratios (see Szumilas, 2010 for an explanation of odds ratios) the authors conducted direct comparisons between NRT, bupropion and varenicline with placebo. They found that:

This review found that NRT, bupropion and varenicline are all effective treatments for smoking cessation

NRT (Nicotine Replacement Therapies)

• Taking NRT significantly increased the odds of quitting compared to placebo (OR = 1.84, 95% CI 1.71. to 1.99)
• The main side effect of NRT was skin sensitivity and irritation (up to 54% of users). However, this rarely leads to treatment withdrawal. Due to limited data no analyses on serious adverse events was conducted

Bupropion

• Taking bupropion significantly increased the odds of quitting compared to placebo (OR = 1.82, 95% CI 1.60 to 2.06) but not NRT (OR = 0.99, 95% CI 0.86 to 1.13)
• The most common adverse events reported for bupropion were insomnia (30-40% of patients), dry mouth and nausea. The use of bupropion was associated with seizures occurring in 1:1,500 users, which was lower than previous estimates (1:1,000).  There was a marginal, but not significant, increased risk of serious adverse events while taking bupropion (2.5% likelihood) compared to placebo (2.2%)

Varenicline

• Taking varenicline significantly increased the odds of quitting compared to placebo (OR = 2.88, 95% CI 2.40 to 3.47) and to both NRT (OR = 1.57, 95% CI 1.29 to 1.91) and bupropion (OR = 1.59, 95% CI 1.29 to 1.96)
• Of the available evidence, the most common adverse event caused by varenicline was nausea. Varenicline had no increased risk of serious adverse events compared to placebo. However, the authors note that evidence for the safety of varenicline is still under investigation

More evidence is needed before the promising treatments cytisine and nortriptyline can be recommended for smoking cessation

Secondary analyses demonstrated that different types of NRT administration (patches, gum etc) were generally as effective as each other. Interestingly, a combination of different NRTs is more effective than single formulations and leads to comparable odds of quitting as varenicline.

Whilst there was a smaller evidence base for other pharmacotherapies such as cytisine andnortriptyline (partly because they are not licensed in Europe or the USA) they also increased the chance of quitting compared to placebo. Of the other alternative pharmacotherapies subject to the meta-analyses only clonidine was found to be an effective treatment (although there were notable adverse effects); SSRI’s, MAOI’s, anxiolytics and opioid agonists generally had poor outcomes.

Conclusions

The review of the data on pharmacotherapies for smoking cessation suggests that the most common treatments all increase the odds of smoking cessation.

The authors conclude that:

Efficacy for NRT, bupropion and varenicline is well-established across a strong evidence base.

There was also some evidence that emerging treatments such as cytisine and nortriptyline may also improve odds compared to placebo, but more evidence is needed. Finally, the authors suggest that future research should attempt to determine retrospective safety and efficacy of varenicline and NRT.

Links

Cahill K, Stevens S, Perera R, Lancaster T. Pharmacological interventions for smoking cessation: an overview and network meta-analysis. Cochrane Database of Systematic Reviews 2013, Issue 5. Art. No.: CD009329. DOI: 10.1002/14651858.CD009329.pub2.

Szumilas M. Explaining odds ratios. J Can Acad Child Adolesc Psychiatry. 2010 Aug;19(3):227-9.

Medicines improve your chance of quitting smoking. Lifestyle Elf, 31 May 2013.

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Illegal drug use during pregnancy is associated with a host of complications for both Mother and baby

This article was written by Abi Rose for the Mental Elf website, you can read the original here

The potential dangers of illegal drug use are never far from the media spotlight, and drug use during pregnancy may be associated with particular health problems both for the Mother and baby. Drug use during pregnancy has been linked with a number of negative outcomes, for example, cocaine use has been linked with an increased risk of placental abruption, while opiate use has been linked with neonatal abstinence syndrome and low birth weight. However, much of this research has failed to control for cigarette smoking status, which in itself has been associated with an increased risk of placental abruption, poor fetal growth, and late intrauterine death. Given that the majority of illegal drug users smoke, it is important to determine which maternal and prenatal health issues are specifically associated with illegal drug use.

Earlier this year, the Acta Obstetricia et Gynecologica Scandinavica published a retrospective cohort study, aimed at determining specific maternal and prenatal health issues associated with illegal drug use while controlling for cigarette smoking. They found that illegal drug use was associated with several serious health implications beyond that of smoking cigarettes.

Methods

The study compared 561 drug using women with 4,463 who had reported smoking cigarettes during pregnancy

Black and colleagues accessed the Aberdeen Maternity and Neonatal databank to identify women who had smoked during pregnancy, and contacted specialist ante-natal clinics in the same area of Scotland to identify women who had taken illegal drugs during pregnancy. 561 women were identified as illegal drugs users while pregnant. Of this group, 459 (82%) were prescribed methadone, 433 (77%) used heroin, 387 (69%) used benzodiazepines, and 190 (34%) used cocaine. The majority (85.6%) used more than one illegal drug and smoked cigarettes (96%). This drug using group was compared to 4,463 women who had reported smoking cigarettes during pregnancy.

Maternal baseline data included age, body mass index, and parity (childbirth history).

Primary outcome measures were:

• Low birth weight (birthweight less than 2,500g) & Standardised birthweight score (SBS takes into account gestation, fetal sex, and maternal parity)
• Neonatal unit admission
• Perinatal death (stillbirth and fetal loss after 20 weeks gestation, and neonatal death up to 7 days of life)

Other outcome measures were:

• Gestational hypertension (diastolic pressure >90 mm Hg on two occasions at least four hours apart, or a single reading of >110 mm Hg; from 20 weeks gestation onwards in a previously normotensive woman)
• Pre-eclampsia (gestational hypertension plus ≥1 episode of proteinuria of 0.3 g/24 hrs)
• Antepartum haemorrhage (hospital attendance with vaginal bleeding beyond 24 weeks gestation)
• Deep vein thrombosis (a radiological diagnosis of venous thrombus made during pregnancy)
• Assisted delivery
• Caesarean section
• Preterm delivery (delivered <37 completed weeks gestation)
• Induction of labour (artificial rupture of membranes or use of prostaglandins to initiate labour)
• Oxytocin augmentation (intrapartum oxytocin use after spontaneous onset of labour)
• Manual removal of placenta
• Postpartum haemorrhage (estimated blood loss >500ml)

Results

Babies exposed to illegal drugs were more likely to have a low birthweight and be admitted to a neonatal unit

In terms of baseline maternal differences, illegal drugs users were less likely to be aged under 20 or over 35 years, or to be primigravid (pregnant for the first time). In addition, illegal drug users were 50% more likely to be underweight than women who smoked cigarettes only.

The authors calculated adjusted odds ratio (AOR) with 95% confidence intervals (CI) to identify associations between illegal drug use during pregnancy and maternal and neonatal outcomes, and to determine whether these associations were significantly different from those between cigarette smoking and outcomes.

Babies who were exposed to illegal drugs were more likely to

• Have a low birthweight [AOR 1.9, CI 1.4-2.6]
• Be admitted to the neonatal unit [AOR 16.1, CI 12.9-20.1]

Women who had used illegal drugs during pregnancy were more likely to have

• Antepartum haemorrhage [AOR 1.6, CI 1.2-2.1]
• Deep vein thrombosis [AOR 21.1, CI 8.8-50.8]
• A preterm delivery at any gestation [AOR 1.6, CI 1.3-2.1].

However, women who had used illegal drugs during pregnancy were less likely to develop gestational hypertension than those who smoked cigarettes [AOR 0.3, CI 0.2-0.4].

Conclusions

The authors conclude that there is an:

Increased risk of antepartum haemorrhage, preterm delivery, low birth weight infants and admission of infants to the neonatal unit in pregnancies affected by illegal drug use, over and above that which can be explained by the effects of smoking cigarettes. This study also identified a lower prevalence of gestational hypertension in women using illegal drugs.

The authors suggest that the reduced risk of gestational hypertension in the women using illegal drugs may be due to lower BMI and the fact that many illegal drugs have a direct hypotensive effect.

The authors also suggest that although smoking is associated with a low BMI, the finding that women using illegal drugs still had a significantly lower BMI:

May be a reflection of these women investing more time and energy on satisfying their addiction than ensuring an adequate dietary intake.

Strengths and limitations

Future prospective studies should gather more information about substance use and confounding factors

It is important to correctly identifying which behaviours are associated with specific health problems, and to help patients improve their own health as well as that of their children. This is a fairly large cohort study that has identified health problems which are specifically associated with illegal drug use during pregnancy.

However, given that this is a retrospective study, there are limitations. For example, it is possible that some of the ‘control’ cigarette smokers had also taken illegal drugs during pregnancy but were not known to the specialist ante-natal clinics. In addition, smoking behaviours (e.g. number of cigarettes smoked per day) were not known; it is possible that the illegal drug users also smoked significantly more cigarettes. Although the study suggested significant effects of BMI, these must be taken with caution as 24% of this data was missing for the illegal drug users.

To determine whether these findings are valid, future research needs to conduct a prospective study in which a greater level of information can be obtained in terms of drug, alcohol, and smoking use during pregnancy while taking into account potentially confounding factors such as social deprivation and diet.

Links

Acta Obstet Gynecol Scand. 2013 Jan;92(1):47-52. doi: 10.1111/j.1600-0412.2012.01519.x. Outcomes of pregnancy in women using illegal drugs and in women who smoke cigarettes. Black M, Bhattacharya S, Fairley T, Campbell DM, Shetty A. [PubMed abstract]

Kuczkowski. The effects of drug abuse on pregnancy. Current Opinion in Obstetrics & Gynecology 2007 Dec;19(6):578-85. [PubMed abstract]

Pregnancy and complex social factors: A model for service provision for pregnant women with complex social factors (PDF). NICE CG110, 2010.

Grimes and Schulz. Making Sense of Odds and Odds Ratios (PDF). Obstetrics & Gynecology 2008 Feb; 111(2 Pt 1): 423-6. doi: 10.1097/01.AOG.0000297304.32187.5d.

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