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A recent first-of-its-kind study conducted by the LKS Faculty of Medicine of the University of Hong Kong (HKUMed) found that mislabelled NSAID (Non-Steroidal Anti-Inflammatory Drug) allergies for stroke patients hinders the use of effective medications for them, leading to poorer treatment outcomes. It also revealed that when stroke survivors with NSAID allergy labels underwent testing, 80% were found to be mislabelled. The research highlights the significant impact of mislabelling on patient care and outcomes, emphasising the urgent need for thorough evaluation and management of drug allergies. The findings were published in the international journal Stroke [link to publication].

Background
Stroke remains the second most common cause of death and the third-leading cause of disability globally. Medical treatment after stroke is important for preventing a recurrence and other cardiovascular complications. Aspirin is an NSAID, known for its efficacy in both the treatment and prevention of various cardiovascular diseases, such as coronary heart disease. Its early use after stroke is recommended to reduce the risk of another potentially disabling and fatal stroke by up to 60%. However, a previous HKUMed study showed that 6-7% of the Hong Kong population have suspected drug allergies in their medical records, one in five of which is linked to NSAIDs, like aspirin. With NSAID allergy labels, patients are prohibited from receiving aspirin, which may result in an adverse impact on stroke or cardiovascular outcomes.

Research findings and significance
Under the supervision of Dr Philip Li Hei, Clinical Assistant Professor from the Department of Medicine under the School of Clinical Medicine at HKUMed, an undergraduate medical student Cheryl Tsui Cheuk-wun conducted the world’s first study to identify the association between NSAID allergy labels and poorer cardiovascular outcomes among 1,003 patients with ischaemic stroke when she undertook research attachment during her Year 3 Enrichment Year (EY). EY is a compulsory credit-bearing component for HKUMed’s MBBS III students, allowing them to take charge of their learning and tailor activities to their interests. Students can enhance their total learning experience through service/ humanitarian work, research attachment, or intercalation.

In collaboration with the HKU Immunology & Allergy and HKU Stroke teams, the study, which analysed electronic health care records in Hong Kong between 2008 and 2014, compared the prevalence of allergy labels among the general population (7,337,778) and stroke patients (1,003). The findings revealed that NSAID allergy labels were significantly more common among patients with stroke and that those labelled with NSAID allergies were less likely to receive aspirin following a stroke, thus facing a 7.44-times greater risk of death and a 6.1-times greater risk of major adverse cardiovascular events. Alarmingly, when stroke survivors with NSAID allergy labels underwent testing, 80% were found to be inaccurately labelled.

Dr Gary Lau Kui-kai, Director of HKU Stroke and Clinical Associate Professor in Neurology in the Department of Medicine at HKUMed, emphasised the detrimental effects on stroke patients who are unable to take aspirin. ‘It is important for patients with unverified drug allergies to undergo evaluation to see if they can safely use NSAIDs again,’ he stated.

‘Patients were often astonished to learn that the allergy labels they had for years were incorrect, and that they could have safely used aspirin all along,’ said Cheryl. ‘As an undergraduate medical student, it is incredibly rewarding to realise that my research during my Enrichment Year can significantly influence clinical practice and patient outcomes.’

‘The research revealed that the majority of drug allergy labels in Hong Kong may be inaccurate, yet most patients have never gone through a proper drug allergy evaluation’, said Dr Philip Li. ‘These mislabelled allergies compel patients to use less-effective medications, which can pose significant health risks, including potentially dangerous or even fatal consequences.’

Dr Li emphasised the urgent need to expand drug allergy testing services in Hong Kong. He advocated innovative strategies, such as empowering community pharmacists to lead drug allergy evaluations in collaboration with HKUMed. He believed that this approach would both address the current gaps in the healthcare system and promote better patient outcomes and overall public health.

About the research team
This interdisciplinary study at HKUMed was led by Cheryl Tsui Cheuk-wun, a Year 4 student in the Bachelor of Medicine and Bachelor of Surgery (MBBS) programme; and Dr Gary Lau Kui-kai, Clinical Associate Professor, and Dr Philip Li Hei, Clinical Assistant Professor, both from the Department of Medicine, School of Clinical Medicine. 

Other members included: Hugo Mak Wai-fung, HKUMed MBBS/ Master of Medical Research student; Dr Valerie Chiang from Queen Mary Hospital; and Wong Yuen-kwun from the Department of Medicine under the School of Clinical Medicine at HKUMed.

Media enquiries 
Please contact LKS Faculty of Medicine of The University of Hong Kong by email (medmedia@hku.hk).