DISCUSSION

In our study, we found a significantly worse quality of life (RHINASTHMA total and subdomain scores) and symptoms control (CARAT total and subdomain scores) in AR patients with comorbid asthma than in patients with AR alone. Such associations were not influenced by any physiological variables. However, we found that the association was significantly higher among non-obese participants compared to obese ones, when assessed through RHINASTHMA-upper symptoms score but not with CARAT. We also observed country-specific variations in the RHINASTHMA and CARAT total scores. Although one previous study compared the individual/social burden of disease between asthmatics and asthmatics with concomitant AR, unlike ours, that study did not compare the difference of disease control and HRQoL between the two groups of patients24.
It is well-known that several triggers such as seasonal meteorological changes, pollen season, air pollution, or even occupational exposures may lead to poor quality of life of asthmatic patients with or without AR 8,25-27. It has also been observed that AR patients are often reported to have poor control over their symptoms if persistent comorbid asthma is present28-31. Although no direct comparative study on the control and HRQoL of AR and AR with asthma has been reported yet, our findings well reciprocate the previous results. Asthma and AR share eight common genes (CLC, EMR4P, IL5RA, FRRS1, HRH4, SLC29A1, SIGLEC8, IL1RL1 ) that are presumed to describe the link for multimorbidity32. They also share common risk factors such as atopic genetic background (for the allergic endotypes), environmental exposures (allergens, moulds, indoor and outdoor air pollution, some respiratory viruses, etc.), type of occupation, and active tobacco smoking.
Our findings add important clinical knowledge to the existing strategies for the management of AR with concomitant asthma. Although AR and asthma are two different diseases with distinct clinical features, when AR persists with asthma, either condition is often overlooked31,33 due to the lack of a combined tool for monitoring control and HRQoL of both diseases at the same time. Despite the well-established guidelines of ARIA and GARD for a new management protocol for AR and asthma together10,12,34-37, reports adopting these guidelines in the management of AR with persistent asthma are still lacking. Our findings would help guide practitioners to use the appropriate assessment tools while treating such patients. Our findings underline the impact of respiratory hypersensitivity conditions in the quality of life of patients and call for prevention and public health strategies to diminish the burden of these conditions. Currently there are effective treatments for AR and asthma, several risk factors are known (e.g., allergies, rhinitis, tobacco smoke) and tools to control the disease have been developed. However, we are still uncertain how to prevent AR patients from developing asthma, allergen immunotherapy being the current only attempt. Preventive measures should be able to change the natural history of the disorder, avoiding asthma development in patients with AR and/or evolution through providing its control38.
Our study has some limitations. Firstly, considering that subjective symptom-rating scales may not be entirely accurate, the risk for potential bias could not be completely avoided. However, we used standardized instruments, and therefore the possibility of such bias was marginal. Secondly, the considered period might be insufficient to evaluate the quality of life and the control appropriately. Thirdly, other comorbidities might have modified the patients’ responses. Despite these limitations, our findings are derived from incident patients drawn from the general population of three European countries in which AR and asthma diagnoses were made by a doctor. However, due to the small sample size, it is not possible to indicate whether these results may be generalized. Further studies, after controlling for potential confounders and biases in larger populations, are therefore warranted.