Missing Data

By Matt Curtis

Looking back to the situation five or ten years ago, we’ve made major progress in building an evidence base around overdose, both in terms of the prevalence of overdose in different kinds of drug using communities and the efficacy of prevention and response programs. More research is happening now than ever before, at a bigger scale and in more places.

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As with any new area that epidemiology sticks its nose into the first wave of research is often all about counting: how big is the problem, what kind of people is it affecting, where and in what way? Although there’s work to be done still on these kinds of most basic questions, we have a pretty good idea of the scale of the overdose problem in many parts of the world and enough solid information to take action at a public health level without fearing we may be wildly off base. (Some people would disagree with that statement, which may deserve a fuller discussion on OPA; for now I’ll only note that doubters of overdose prevention programming are nowadays mostly confined to the wing of public health usually referred to as “Wrong.”)

So what should come next? Here, thinking out loud, are eight areas that I think researchers could fruitfully investigate:

(1) Smoking and cardiovascular and lung disease: How much is tobacco smoking-related cardiovascular disease related to cocaine (and other stimulant) overdose?  Similarly, how much is smoking, COPD, chronic bronchitis and other chronic lung disease related to opioid overdose?  My gut tells me the answer in both cases is ‘probably a lot, especially in combination with other health problems,’ but there’s very little published information on these subjects. And I don’t know a single harm reduction organization that has a serious tobacco harm reduction or smoking cessation program (though that may be just because I need to get out more). Are we failing people on this because everyone’s just thinking that smoking is pretty punk rock and part of the scene and all I need is nic-fitting crack users running around my drop-in center?

(2) Risk factors for fatal overdose: By now, many studies have examined risk factors for nonfatal overdose, especially for opioids, and I think we’ve got a pretty good picture of the main issues (more on which in an upcoming OPA article). But what about fatal overdose? We have some evidence for basic risk factors, like older age, but a less than clear understanding of why risk is heightened (e.g. with age, probably comorbidities, but we need details). It’s much more complicated and potentially expensive to organize studies on overdose death, but doing so will fill gaps in our understanding of how to best target overdose services.

(3) We need more prospective studies: When is someone going to do a great time-to-event study (‘survival analysis’) or in general prospective (forward-looking) studies to look at how people are using the information and naloxone we give them? Wouldn’t this be a better way of assessing whether certain kinds of training or naloxone distribution systems or prevention messages are more effective than others, compared to all those damned cross-sectional surveys common to underfunded harm reduction organizations?  The N-ALIVE study in England is kind of doing that – and most likely there will be lots of interesting data to examine for years to come from that study.

One thing such studies could be used to investigate is (4) whether overdose prevention programs reduce overdose incidence.  We now have a growing and notably consistent body of evidence at an ecological level that strongly suggests scale-up of overdose education and naloxone availability reduces overdose mortality. But it’s much less clear that current overdose prevention efforts are reducing how often nonfatal overdoses occur (and for whom, in what circumstances, what kinds of overdoses, etc.).

(5) What would a ‘complete package’ overdose prevention program look like?: Related to mortality reduction is the question of what might a truly comprehensive overdose reduction effort look like.  Naloxone has gotten most of the attention in recent years, but it’s certainly not the only important tool available, and isn’t relevant for non-opioid users, doesn’t on its own do anything for prevention, and may not even be the most important tool to reduce overdose mortality risk for opioid users (if we had to choose only one intervention, which we don’t). Opioid substitution therapies and safer injection sites are both known to greatly reduce overdose risk but we have strangely few examples of where both those services are also available alongside naloxone distribution efforts (maybe in Germany?). And what else is there? How important are other drug treatment modalities? Access to psychiatric services? Social or economic assistance? What do we do about cocaine or prescription opioid users?

Every locality will have its own nuances, but if we’ve been able to come up with evidence-based core packages of services and policies for the prevention, care and treatment of numerous infectious and chronic diseases, why not for overdose?

(6) Are prevention messages mostly wishful thinking?: Speaking of overdose prevention education, I often have the feeling that everything we say about not mixing, not using alone, minding one’s tolerance, and so on is very closely akin to saying “Remember not to get high today.” That’s not an argument for skipping prevention education, and I have a deep (and potentially unfounded) belief that behavior around overdose risk will change in communities over time – just as behavior around injection and HIV risk has changed – the more we talk about it. But I’d really love to see some actual evidence for this. We need a team of anthropologists or sociologists running around looking at what people actually do with the overdose information we give them.

(7) Do overdose services bring more people into health care?  This is a question beloved, for not entirely bad reasons, by AIDS funders who we trick into supporting overdose programs. There’s some anecdotal evidence that new overdose services are exciting and draw more people into other kinds of health services, especially in environments where harm reduction programs aren’t well developed beyond basic syringe exchange. I’ve heard LOTS of stories from outreachers at this point about waves of new participants running through the door once naloxone was being offered – and subsequently getting hooked up with clean injecting gear, VCT, primary healthcare, etc. We need more than nice stories though, and we can start by designing a simple way to identify and quantify new clients when overdose services are started.

(8) Which gear to pack?: This is a smaller issue than the things described above, but it’s been bugging me: Do people really and truly need to use intramuscular needles to inject naloxone?  I hear about lots of people using insulin needles, and basically no cases of that not being effective. I think there are a few studies that are starting to better incorporate questions about what needles/syringes were used in OD response, but I’m not sure I’ve seen anything published, and definitely not anything that’s looked specifically at the efficacy of short vs. long needles in naloxone administration.

Every time I ask educated types about this they say something to the effect of, oh yeah, definitely go with an IM needle, and if you must use an insulin or tuberculin needle, inject into the tongue. Fine advice in the absence of definitive evidence, but it’s a major practical problem in a lot of places where I work, where people absolutely refuse to carry one extra potentially unnecessary piece of drug gear because on a day to day basis they are very likely to have a cop greedily searching their pockets and looking for any excuse to make their day very bad. My question is do we really need to be doing the work to ensure that people are able to carry extra IM syringes because they really are a better delivery device for naloxone, or can we drop it and tell people it’s OK to use the syringes they’re already carrying for their drugs?