‘Cocaine use is extremely common’: Data suggest testing for drug prior to GPA diagnosis
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Key takeaways:
- Patients with destructive nasal lesions should complete a urine toxicology test for cocaine before they are diagnosed with granulomatosis with polyangiitis.
- Patients using cocaine will not see full benefits of GPA therapy, researchers said.
Physicians should screen patients for cocaine use before making a diagnosis of granulomatosis with polyangiitis, according to data published in Rheumatology Advances in Practice.
Study co-author Alan D. Salama, MBBS, MA, PhD, FRCP, a nephrologist with the University College London department of renal medicine and the Royal Free Hospital, in London, added that patients suspected of having GPA should be screened via urine analysis for the use of cocaine before beginning any kind of immunosuppression therapy.
“To minimize the side effect of the drugs we use and maximize the potential of them responding, we need them to stop using cocaine,” he said.
Healio sat down with Salama to discuss the impact of cocaine use on rheumatology patients presenting with potentially unidentified vasculitis, or otherwise unknown nasal and sinus inflammation.
Healio: Why was this study performed?
Salama: We are getting more and more referrals with patients who are suspected of having vasculitis, some of whom have had a history of cocaine use. We really wanted to have a look at what the outcomes were in people who developed problems with their sinuses and nose as a result of cocaine, and what it looked like compared with what has previously been published, as well as how they did with some current treatments that we use at the moment.
The main aim is really to understand, compared with the previous publications that have said there is a very particular pattern with patients who take cocaine in terms of what they get and their antibody profiles. We were not really seeing that, and so we wanted to have an experience of what we have seen at two large vasculitis centers. We did a retrospective analysis to try to understand how they presented, what happened to them, where they got treated, what they were treated with and what the outcomes were.
Healio: What is the main takeaway for rheumatologists?
Salama: There are two main messages. First, cocaine use is extremely common. I think in the United Kingdom, it is one of the most commonly abused drugs. It is relatively cheap and a lot of people are using it. The demographics have changed. It is very often associated with relatively limited sino-nasal inflammation, which looks, for all intents and purposes, like vasculitis. You might even have some vasculitis when you get the biopsies.
However, what we found was that treatment with an anti-inflammatory, steroids or immunosuppressants, without stopping the use of cocaine, really does very little to stop the process in its tracks. The main conclusion that I think rheumatologists should come away with is, if patients have limited sino-nasal disease, with or without a positive antineutrophilic cytoplasmic antibody (ANCA) presence, and physicians suspect a limited form of vasculitis, they should screen for vasculitis, like we would generally, to see if other organs are involved. However, they should also consider screening for cocaine use. The main reason for that is if you can stop people from using cocaine, many of their symptoms will likely improve.
The other main message was that, in a significant portion of patients, despite the fact that they told us they were no longer using cocaine, when we tested them they were positive.
Healio: Should these findings change the way rheumatologists practice? In what ways?
Salama: Similar to how people underestimate how much alcohol they use, there is a disconnect between people who think they are really not using much cocaine, when in fact, when you test them, they are positive for cocaine, which means they have been using it within the last 3 days. As a result of that, we have started a help strategy where we get them in touch with addiction psychologists to see if we can get them off the cocaine. There is a real disconnect between what they think they are doing and what they are actually doing.
The other sort of important thing is that, when we are treating them with immunosuppressants, we are subjecting them to drugs that can have significant side effects and we think that the potential benefit is much lower if they are still using cocaine.
Healio: Does this study indicate that there should be changes in the way GPA is diagnosed?
Salama: No. Many of the diagnostic tools that we have available to us, such as biopsies of the nose and ANCA-testing were all very similar in the patients using cocaine compared with idiopathic GPA. The difference is that they typically had fewer systemic symptoms and organ involvements apart from the nose and the sinuses.
Healio: What kind of dangers exist for patients who are misdiagnosed with GPA?
Salama: In terms of diagnosing somebody with GPA when what they have got is not a primary autoimmune disease, but rather a secondary problem related to a substance that they are taking, we think the risk/benefit of treatment with immunosuppressants and steroids can lead to more problems and rather than the benefit that we would normally see in patients who have autoimmune GPA. It has become our policy to test urine in patients who have sino-nasal disease, and we have been extremely surprised at how often they are positive for cocaine when you look at the correct population and you apply the test.
Healio: What kind of clinical changes should physicians make in order to reduce the frequency of misdiagnoses?
Salama: It is sort of similar to GPA. You cannot tell on clinical examination, on histology, or often with the ANCA tests. You can, though, tell if they have been using cocaine within the last few days. One of the other conclusions we came to was that the previous descriptions of ANCA patterns that were associated with cocaine use do not hold true for our population. One reason for that may be that cocaine is less adulterated now than it was before. Cocaine used to be mixed with another drug that had a tendency to stimulate autoantibody production.
Healio: Should urine testing for these types of drugs be more common when investigating potentially related diseases such as GPA?
Salama: The answer, unfortunately, is yes. I think a screening test like we would do for other forms of vasculitis should include a urine test for cocaine, because it changes what you would do next. You might not start treatment straightaway but consider talking with the patients about stopping use of cocaine, helping them stop using it. If there is still inflammation, there is a much greater chance the drugs will work at that stage.
Healio: Do patients ever get defensive when it is suggested that this might be a cause of their illness?
Salama: It is a very difficult conversation to have. Patients do not like admitting that they take it. Part of that is because there is a stigma associated with it and part of that is because they are in a clinic, and they might not like to admit they are behaving in a way that might be contributing to their disease. They do not like to think that they are making the problem worse. They feel there might be a sense of blame, or a perceived blame, that will be associated.
We try not to be judgmental about it, in the same way you would discuss alcohol or smoking with a patient. Some patients, when you confront them and tell them what you think the main driver is, do not come back. Some do come back and try very hard to stop.
Healio: Do you have anything else to add?
Salama: I think we are probably underestimating the size of the problem in that we have not had a policy, prior to this study, of testing everyone when they present. So, we relied on talking to the patients, and maybe there was a bit of physician bias as to who might be taking cocaine and who might not be. When we have looked more systematically, we find that it is much more common than we thought before.
Reference:
Gill C, et al. Rheum Adv Prac. 2023;doi:10.1093/rap/rkad027.
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