Special Episode - Depression in pregnancy and the postpartum period: should we screen everyone?

The short answer to this question, according to a new guideline published in CMAJ, is “No.”

In this special episode, CMAJ editor in chief, Dr. Kirsten Patrick, talks to Dr. Eddy Lang, lead author of the guideline entitled Recommendation on instrument-based screening for depression during pregnancy and the postpartum period produced by the Canadian Task Force on Preventive Health Care. They discuss why there’s not enough evidence to support a recommendation to screen routinely, why that doesn’t mean that depression in pregnancy and the postpartum period is not important to diagnose, and in what circumstances use of a screening instrument might be helpful.

Blair and Jola will be back next episode.

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Transcript

Dr. Kirsten Patrick:
Welcome to this special episode of the CMAJ Podcasts. I'm Dr. Kirsten Patrick, editor-in-chief of CMAJ. This episode is part of an occasional series that focuses on new practice or policy guidelines published in CMAJ. Today, I'm discussing a guideline from the Canadian Task Force on Preventive Health Care entitled, Recommendation on instrument-based screening for depression during pregnancy and the postpartum period. The lead author is Dr. Eddy Lang, he is an emergency physician and a professor at the Cumming School of Medicine at the University of Calgary, and he's also chair of the Task Force's Pregnancy and Postpartum Working Group. Thanks for joining me, Eddy.

Dr. Eddy Lang:
Yeah. It's great to be here, Kirsten. Thank you.

Dr. Kirsten Patrick:
So depression during pregnancy and the postpartum is a topic that's very close to my heart. Not least because although I'm an anesthesiologist by training, I did take a little detour in my career and I happened to work as a clinician-researcher in perinatal mental health for a year and a half. There is an abundance of research linking depression in pregnancy and the postpartum to adverse, short, and long-term outcomes for both pregnant people and their offspring. So it's clearly important to detect and treat it early. And in light of that, the recommendation made in this new guideline may baffle some people. Eddy, what is the recommendation?

Dr. Eddy Lang:
Let me read it to you verbatim, Kirsten, it goes like this, "We the Canadian Task Force recommend against the use of screening questionnaires with cutoff scores for all pregnant and postpartum people up to one year after childbirth." And we use grades, so it's important to note that this is a conditional recommendation as opposed to a strong recommendation, and it's based, unfortunately, on very low certainty evidence. We also emphasize because of the importance of the alternative to screening that usual care includes questions about and attention to mental health and wellbeing in pregnancy and the postpartum period. So that's the recommendation.

Dr. Kirsten Patrick:
Let's talk about the evidence because you say this is a conditional recommendation that's based on evidence that's quite thin. What did you and the Task Force do, and what did you find?

Dr. Eddy Lang:
The first time we weighed in on this topic was in 2013 when the Task Force came out again against screening using standardized questionnaires, universal application, and a cutoff score. But we felt it was important to update the guideline because a number of years had elapsed and there was still quite a bit of practice variation that we were aware of across the country. So we conducted a systematic review and uncovered, despite wishes and desires that we would've found more, there was actually only a single randomized controlled trial that compared screening to non-screening in this patient population.

There has been multiple other trials that have compared the combination of screening and treatment to no screening, but we really wanted to narrow it down as we are often asked to do at the Task Force on the question of screening alone. So this one trial, which we actually missed on the first go around showing you that there are limitations to the whole process was published out of Hong Kong in 2011 and had a number of limitations. It was a relatively small sample, the outcome ascertainment was problematic and there were very few cases of depression in both the intervention and the control arm, leaving us to be quite uncertain about the evidence that we had found. Only a single trial. And our approach at the Task Force is that in order to make a recommendation for an intervention on asymptomatic individuals, you do need more robust evidence than what that single trial represented.

Dr. Kirsten Patrick:
Did you only look at randomized controlled trials?

Dr. Eddy Lang:
Yes. The systematic review protocol, which we had published ahead of time made it clear that if we wanted to really focus in on the effect of screening alone, there would be certainly advantages to primarily looking at randomized controlled trials that compared screening to non-screening. That's not a perfect approach, and some would argue that there is rich evidence to be gathered in the non-RCT literature. But our methodology and what we've been using for all of our guidelines is to try to reduce the risk of bias in the research that we uncover through the systematic reviews. And as a result, nearly all of our recommendations are based on guidelines and systematic reviews that focus on randomized trials.

Dr. Kirsten Patrick:
That makes perfect sense. Now, when you were talking about the population that you were looking at, you were talking about asymptomatic people. And I think you're very clear in the guideline who you are not including in this recommendation. Do you want to just emphasize that for me?

Dr. Eddy Lang:
Yeah, that's correct. So of course, anyone with a history of mental illness or someone who is in a particularly high-risk group, whether that be as a result of sociodemographic factors or substance use disorder, this would not apply. What we are mostly focusing on as most screening tests do is the asymptomatic population. So the vast majority of pregnant and postpartum women who are seeking primary healthcare either through a family physician or another healthcare provider. I would just add that what we are including is, of course, anyone with a family history of mental illness and someone who might be otherwise at risk for mental illness. But I think in general, if you are talking about someone who has suffered from depression before, you're no longer talking about screening an asymptomatic person, you're talking about identifying a recurrence in someone who's already identified themselves as being at risk for mental illness.

Dr. Kirsten Patrick:
Absolutely. Because the observational evidence does show us that people who have had a history of depression are more likely to become depressed during pregnancy or in the postpartum, so any good clinician would genuinely already be asking that person about any particular symptoms that they might have. So why do the update of the guideline?

Dr. Eddy Lang:
This isn't actually an update. We have two processes within the Task Force, one is a reaffirmation of an existing guideline, the other is a complete renewal of a existing guideline based on a brand new systematic review and a new set of guideline recommendations. We have a pretty robust process where we engage with stakeholders, present topics, and also always have a open door to our partners in healthcare across Canada for what they feel is an important guideline to address. So when we were looking at our topic prioritization process at the Task Force, postpartum depression and pregnancy-related depression, as well as screening for depression in adults and in children and adolescents bubble to the top as an important topic to address, both because there is considerable variation in practice and there is what we thought would be a robust emerging literature that might help us redefine and reassess the state of the evidence and potentially make new recommendations.

I mean, nothing would've made us happier than to uncover robust body of evidence and enable us to make a more convincing and positive recommendation on screening. But as I mentioned earlier, we don't recommend adding interventions to asymptomatic people unless there is robust evidence that it changes not only the rate of diagnosis, but it has to also change patient-important outcomes. So maybe this is a message to the research community. We do need these trials that might be able to show that screening for depression will actually improve functional outcomes, improve functional status in those afflicted with postpartum depression. And if that were the case, it would be our duty to make a positive recommendation in that case.

Dr. Kirsten Patrick:
Absolutely. It's actually quite shocking to me how little evidence there is on screening as an intervention.

Dr. Eddy Lang:
We are also, as I mentioned, looking at screening for depression in adults, children, and adolescents, and there is more of a robust evidence based there, that's all I can say at this point in time. But you're right, it was quite disappointing and even close to shocking to not see more research focusing in on the screening intervention alone. And maybe the reason that the one trial did not show the kind of benefits or the reliability or trustworthiness that we were at hope for may in fact be related to the use of the screening tool that was used, the EPDS.

Dr. Kirsten Patrick:
Right. So let's go back to this recommendation. It's a negative recommendation about what clinicians are not recommended to do, but essentially by extension the Task Force is saying that there are some things that a good practitioner who sees pregnants and postpartum patients or clients should do, am I right?

Dr. Eddy Lang:
That's correct. And we debated this at length because we know that practice may not be uniform across the country. We know that primary care is under a great deal of pressure at the present time with a lot of demand and limited resources to mental health specialty expertise. So with that in mind, we felt that it was important to take those things into consideration and still make sure that we were not minimizing the issue and raising awareness around the importance of being very vigilant and detecting this. It's just that, unfortunately, applying a questionnaire to everyone in your practice who meets these criteria is as yet unproven to improve those outcomes.

Dr. Kirsten Patrick:
So what should clinicians be doing instead then? Should we be case-finding?

Dr. Eddy Lang:
Well, we should, of course, as part of good routine care be asking about the usual things that may be linked to postpartum depression and depression during pregnancy. And these are to some degree, I think some of the common sense things about mood and wellbeing and just general questions about how things are going and maybe even using corroborating evidence from sleep, appetite, and things of that nature, to help us clue in to a case where the postpartum depression may not be obvious or a cult, and maybe detected in that way. So that is basically what we're saying that high clinical vigilance, careful conversations... And this is what came out of our engagement activities with our focus groups of pregnant and postpartum patients. They weren't necessarily that intent on filling a questionnaire, but they wanted to be asked, they wanted to have the conversation, they wanted their clinicians to address these issues during their encounters. And that's what is reflected in the recommendation.

Dr. Kirsten Patrick:
The guideline authors do mention in the guideline that it doesn't mean that you should never make use of a screening questionnaire, it's just in the case of applying it to everybody who's coming in, say for an antenatal appointment or whatever. You give I think the example that it could be quite useful in starting a conversation. Do you suggest that practitioners might still use it as a tool occasionally to kickstart a conversation?

Dr. Eddy Lang:
That's exactly right, Kirsten. And again, this is a conditional recommendation against, not a strong recommendation against. In no way would we want to sanction anyone for using the tool in some way, shape or form. We have no evidence that the harms, although there are many potential harms of universal screening, we're not convinced by evidence that shows that these problems are there. So, absolutely, if a clinician feels that the questions in these questionnaires are helpful as a spark for discussion, or as a reminder for what needs to be asked for, well, then by all means they can be used.

Similarly, in a practice where there's a high concentration of patients who are at high-risk for depression, let's say it's a marginalized population with vulnerability, that might be a case to ignore our recommendations and go ahead and use the screening tool. It's not a one size fits all. And if there are clinicians who feel comfortable just using a conversation and typical questions to ascertain whether there may be signs or symptoms of depression, that should be fine as well.

Dr. Kirsten Patrick:
I was also thinking about the situation of language disconcordance within a practice setting because some of the screening tools are translated into many different languages. It could potentially be useful to have somebody fill it out in their own language, I expect.

Dr. Eddy Lang:
That's a great point. I think another good example of where you might actually be using components of the questionnaire is just in that setting of when translation services are limited and the patient's first language is not the same as that of the practitioner. So for sure, that's an opportunity where deviating from the recommendation is certainly worthwhile. I guess our main issue is that right now there are nine provinces that are to some degree mandating the completion of screening questionnaires as part of the perinatal health record. And we just want to point out that although well-intentioned and potentially a logical thing to do, it is unsubstantiated by evidence, and that's why we recommend against it.

Dr. Kirsten Patrick:
So you talked a little bit earlier about the harms of screening, and we don't really think about identifying depression as being harmful usually, but what do you mean when you talk about harms of screening in this context?

Dr. Eddy Lang:
Well, I think an important consideration is the whole topic of baby blues. As many listeners will know, baby blues is a common occurrence after pregnancy and is usually a self-limited... A problem characterized by a moods and sadness and anxiety and poor sleep, many of the things not uncommon with the early postpartum period. But postpartum depression is different, it requires two weeks of symptoms. And one of the things we are concerned about in applying a universal screening approach is that there could be some overlap or confusion between the detection of postpartum blues or the baby blues and postpartum depression. And although we don't have specific data or evidence on this, we know from other areas of screening that sometimes the screening process will make a diagnosis that is not exactly a false positive, but actually results in a diagnostic label for a either a milder or a self-limited form of depression like baby blues that perhaps in some cases might have been better unknown.

That might be a hard concept for many people to appreciate, but we heard from our patient engagement partners that there are significant long-term consequences to this labeling. It can result in prescribed medications that are not without side effects or complications. And it can result in the labeling of an individual as being a depression sufferer, when in fact, they may not have been, either because they were overdiagnosed or they were a false positive. So that's an additional caveats that we want to bring to your listener's attention and part of the rationale for why we are not endorsing universal screening in this context.

Dr. Kirsten Patrick:
Within the guideline, there is a very helpful table that outlines the different recommendations across jurisdictions in Canada but also compares the current Task Force recommendation to recommendations that are made by other bodies outside of Canada. And that's pretty helpful. What evidence are the guidelines who recommend a different approach using, given the very careful search for evidence that you've done and discovered that it's minimal?

Dr. Eddy Lang:
Well, they're not really all that different, it's just the way in which they're framed. So for example, we're in concordance with a number of the UK recommendations, which certainly emphasize the importance of questioning, but don't necessarily endorse screening as we've defined it as a universal approach involving a questionnaire. Interestingly, the United States Preventive Services Task Force, which generally takes a more pro-screening approach on a number of topics, they endorse screening, but in the caveat that it would be only in circumstances where ample resources are in existence to manage the number of positives, including presumably some false positives that would come about as a result of the screening process.

So if you consider the state of healthcare now in Canada and the strains that we're under as an emergency physician, we regularly have dozens of mental health patients in our emergency departments unable to access inpatient beds because resources are so strained. So if you consider the challenges that both our primary care colleagues and our mental health colleagues are facing, it's even more critical I think that we be judicious in selecting interventions that are going to be used in a universal matter and may generate workload and downstream consequences that are unintended.

Dr. Kirsten Patrick:
You highlight a very important points about some criteria for screening, actually, I think. Because we know that these screening tools are reasonably good, there's a lot of evidence to show that, but we also need to know that they're cost-effective, that using them impacts important outcomes, which you've said, "We don't know well enough because there just isn't the evidence." And then we also need to know that we can act on it, that there is some kind of formal system in place for being able to deal with screen positives, which is what you've raised about the U.S. Preventative Task Force recommendation. And so it does seem that it's indefensible to ask people to screen or have mandates for screening when those screening criteria just simply are not in place.

Dr. Eddy Lang:
I think the Task Force would agree completely with those comments, Kirsten. And we do have quite a bit of evidence. In fact, one of our clinical experts who's not involved in the voting process and remains at arm's length of the process has done a systematic review showing that there are actually limitations to the screening tools. And there is a significant false positive rate and significant false negative rate that need to be contended with. And perhaps in the future, we will find a much more robust tool that meets the criteria of cost-effectiveness and shows us that those who screen positive are at high likelihood of actually truly having postpartum depression and not being missed by the process.

Dr. Kirsten Patrick:
So then my question is where to from here? You've made this conditional recommendation and people will continue to practice thoughtfully, bearing in mind, this conditional recommendation. You've talked about more research that is needed, encouraging research in this field, what else?

Dr. Eddy Lang:
I think our key messages are of course, to primary care providers. And as a conditional recommendation, if someone is already comfortable and inclined to continue using a screening tool as they are now, they can choose to continue that, but they should be aware that the evidence is really wanting. And if they felt that this was something that they could now remove from their repertoire and not be sanctioned for it, that would be a very reasonable approach as well. Our message to policy-makers is to reconsider the mandate to apply universal screening as part of the perinatal record. We accept that cases will be missed and that not all physicians will necessarily be as cautious and as vigilant. Unfortunately, applying a screening tool universally does not appear by the current evidence to solve that problem.

And more and more our guidelines are reaching out to patients and families. So we want to increase awareness about postpartum depression, but we want people to exercise caution that if they are being labeled as potentially depressed as a result of completing a questionnaire, that should be taken with a grain of salt because of our findings which that universal screening is not yet justified. Our message also to the research community is that a definitive trial is required to address this question. And hopefully, our colleagues at the CIHR might see value in a funding call to actually create a more definitive answer to this question.

Dr. Kirsten Patrick:
Excellent. So Eddy, how can clinicians and patients find out more about the guideline, and are there any tools that you have available to help them to understand and implement in their practice?

Dr. Eddy Lang:
Sure thing, Kirsten. The Task Force is really fortunate to work with the knowledge translation team at St. Mike's Hospital in Toronto. And creating recommendations that are implementable and user-friendly is core to our mandate. So as a result of that collaboration, we've created a number of tools that accompany this guideline. So on our Task Force website, there is a dedicated page that both clinicians and patients can refer to, that elaborate on our guideline, speak to the rationale for why we've made this recommendation against screening.

There are lots of resources, including a frequently asked question list, infographics, all of which help explain the distinction between normal good practice and asking good questions and submitting to a standardized questionnaire and what we mean by screening. So we're really proud of this collaboration with St. Mike's, and we believe that these tools are already in wide use around many of our other guidelines will be particularly helpful for people who are considering implementing our recommendations into practice.

Dr. Kirsten Patrick:
Well, I hope that any patients listening to this will feel empowered to either speak to their healthcare provider if they have symptoms or push back on having a universal screening tool offered at them if they don't feel they need it. Thank you for clarifying what you've done and what the guidelines shows.

Dr. Eddy Lang:
Thank you for a great interview and for great questions, Kirsten.

Dr. Kirsten Patrick:
I've been speaking with Dr. Eddy Lang, an emergency medicine physician and professor at the Cumming School of Medicine at the University of Calgary. He's also chair of the Canadian Task Force on Preventive Health Care's Pregnancy and Postpartum Working Group. He and co-authors have published new guidance on use of instrument-based screening for depression during pregnancy and the postpartum period, which is published at CMAJ. I'm Dr. Kirsten Patrick, editor-in-chief of CMAJ, hosting this special episode of the CMAJ Podcast. Blair and Mojola will be back next episode.