Abstract

Background and aim. Anaphylaxis is an allergic reaction of the body, which starts quickly and may become life-threatening. Food, insect bites, or drug(s) are more common triggers. Epipen, a pen injection containing epinephrine, is used for treatment. This study focused on anaphylaxis and the use of its first-line drug in Estonia in 2016–2020. The objectives were (1) to describe, according to age and sex, people newly diagnosed with anaphylaxis in 2016–2020 (2) to estimate the number of people living with anaphylaxis in Estonia as of 31.12.2020, (3) to describe the incidence of anaphylaxis by the year of diagnosis, and (4) to evaluate the proportion of patients who received emergency treatment with epinephrine (adrenaline) in a pre-filled pen among those diagnosed with anaphylaxis in Estonia in 2016–2020.
Methods. The required data for the analysis was obtained from the Estonian Health Insurance Fund’s databases of medical bills’ and from the prescription centre. A frequency table with absolute numbers (n) and relative frequency (%) of absolute values was used to describe grouped characteristics and the median, minimum and maximum to describe continued characteristics. Poisson regression was used to calculate the dence rate (IR) and the incidence rate ratio (IRR), as well as the 95% confidence interval (95% CI) and p-value for both. A p-value less than 0.05 was considered statistically significant. Morbidity rates were calculated to describe incidence and prevalence.
Results. In 2016–2020 the number of firsttime anaphylaxis patients diagnosed was 1,381, of whom 697 were male (50.5%) and 684 female (49.5%). The overall incidence was 20.9 cases per 100,000. Men developed the disease more often than women: it was found that men had 1.24 times higher probability of incidence compared to women (p < 0.05). The highest incidence was recorded among 0–4-year-olds (IR = 6.61; 95% CI 3.85– 11.56 and IR = 49.86; 95% CI 42.88–57.97). Unspecified anaphylactic shock was the most frequently diagnosed condition (ICD10: T78.2), with a primary morbidity rate of 15.49 cases per 100,000, accounting for 71.6% of all diagnoses. Anaphylactic shock due to an adverse food reaction was the second most common diagnosis (ICD-10: T78.0): 317 cases and an incidence rate of
4.8 per 100,000, accounting for 22.2% of all diagnoses. Anaphylactic shock due to drug administrations was diagnosed in 77 cases with an incidence rate of 1.16 per 100,000 cases. The lowest number of diagnosed cases was seen in the case of anaphylactic shock due to serum exposure and anaesthesia, a total of 11 and 1, respectively.
Conclusions. Based on the results of the study, it can be concluded that men are more likely to develop anaphylaxis compared to women, and children aged 0–4 years are most likely to develop the disease. As of 31.12.2020, the prevalence of anaphylaxis in Estonia was 0.2%. Unspecified and food-induced anaphylaxis were diagnosed most commonly, and 47.4% of the newly diagnosed patients used Epipen regularly for emergency treatment of anaphylaxis.