DISCUSSION
This study aimed to assess the impact anaphylaxis has on the QoL and mental health of adults, using validated measures. A new tool developed and validated by our group for measuring anaphylaxis specific QoL for adults12 was employed and scores on scales to measure general QoL and mental health were compared to relevant norm data where available. When comparing scores with norm data, adults with anaphylaxis reported greater stress and poorer general QoL in social and environmental domains. It is unsurprising that adults with this condition report high levels of stress and an impact on social and environmental QoL, given the constant vigilance required to avoid their respective triggers, which involves continually assessing risk in their environment. Those with food allergy also need to assess risk every time they eat and this type of allergy has been consistently related to poorer social lives, impacting on activities such as eating out or going on holiday25. On the other hand, adults with anaphylaxis reported a better general physical QoL than norm values. This may be due to particular characteristics of this cohort that might be different to the norm sample. For example, the majority of the participants in this cohort were educated up to at least high-school level which may indicate a better socio-economic status, an established predictor of better quality of life26 and general health27.
Gender differences were found when exploring differences in anxiety and depression compared to norm data, with only females scoring significantly worse. Almost half of the present sample of female adults also reported moderate to severe anxiety levels. Anxiety due to anaphylaxis has been reported in younger age groups in both males and females5,6. It is unclear why females in this sample reported particularly high levels compared to males. It may be due to females being more likely to report mental health issues28 or they may simply have a greater fear of the consequences of anaphylaxis than men. Exploration of beliefs and understanding of anaphylaxis would be useful, particularly as illness beliefs have been shown to be associated with mental health outcomes and long-term management of allergic conditions such as food allergy29 as well as other conditions such as diabetes30. The findings regarding depression are novel as very little research has measured this in adults with anaphylaxis, although depression is a common co-morbidity with other long-term health conditions31.
Poorer anaphylaxis specific QoL was significantly related to greater stress, anxiety, depression and poorer general QoL across all domains, which highlights the impact anaphylaxis has on day-to-day living of adults with this condition. Important demographic and clinical variables were also related to anaphylaxis specific QoL such as gender (with females reporting a greater impact), younger age, other atopic conditions and number of anaphylactic reactions. Clinicians should take particular note of patients with these characteristics, as they may require further support in managing their condition and/or require psychological support to reduce mental distress.
Direct comparisons across the different causes for anaphylaxis was possible due to the newly validated A-QoL-Adults scale. Those with anaphylaxis to food or with spontaneous anaphylaxis reported a bigger impact on their anaphylaxis specific QoL compared to those with medication or venom as a cause. This may be due to the level of risk assessment and daily effort needed to avoid allergen/s for those with food allergy, or the extra vigilance for those who do not know what causes their anaphylaxis. Significant differences across causes were also seen for those with anaphylaxis to medication, who reported greater depression and poorer overall physical QoL in comparison to those with anaphylaxis to venom. Clinicians should therefore be aware of the different aspects of lives that are affected, depending on the cause of anaphylaxis, in order to ensure appropriate support is in place for optimal allergy management.
In regression models, psychological variables explained a significant amount of variance in QoL after demographic and clinical variables had been controlled for. In the final model, younger age, greater number of anaphylactic reactions experienced and greater anxiety significantly predicted poorer anaphylaxis specific QoL. Reducing the number of reactions people experience is therefore key to improving anaphylaxis related QoL and it is likely that this may also reduce anxiety, which was the strongest predictor of QoL. Those with high levels of anxiety may benefit from psychological support.
Some limitations should be taken into account when assessing the results of this study. First, two thirds of participants who expressed an interest in taking part in the study did not return their study packs and these participants may have potentially responded differently to those who took part. Second, the sample is predominantly White British and as mentioned previously almost 60% were educated to at least a post-high school level (A levels in the UK education system). Third, those with suboptimal or no proficiency in English language were excluded as questionnaires were not available in other languages. This may have had an impact on results although we found no differences across ethnicity. However, group numbers for different ethnic minority groups were relatively low and so we were not able to determine if these results would be the same in different socio-economic strata or ethnic groups where we know rates of anaphylaxis and allergic conditions may vary32. Fourth, data was generated from a single centre, although it is a major regional centre with a wide catchment area outside Birmingham city. Nevertheless, this study reports novel findings in a sample of well characterised adult patients with anaphylaxis which could assist in informing clinical and psychological support for allergy management. Patient education and training for allergen avoidance is needed to improve self-management of anaphylaxis. In addition, help in recognising when anaphylaxis is having an impact on mental wellbeing is key to timely referral to for psychological support.
In conclusion, anaphylaxis has an adverse impact on QoL and mental health of adults across different causes. Anxiety, depression and number of reactions seem to be important in explaining the impact on QoL. Those with anaphylaxis to food or spontaneous anaphylaxis in particular may benefit from support to help improve quality of life. Further multi-centre studies including a larger sample of patients from ethnic minority groups may help gain further insight into the impact of anaphylaxis on QoL and facilitate development of novel supportive interventions.