This study intended to identify determinants of uncontrolled asthma. Age of patients, age of the patients’ living houses, presence of pets in the houses, having rhinitis, exacerbation in the last 12 months, adherence to treatment, and smoking were found to be determinants of uncontrolled asthma.
In this study, asthmatic patients whose age was 35 or above were nearly three times more likely to have uncontrolled asthma when compared with those whose age was between 18 and 34. This finding is supported by studies done in Spain (32), China (33), and Saudi Arabia (15). Similarly, a study done in Jimma, Ethiopia, also stated that the probability of getting well-controlled asthma was more than three times higher in the age group of 14–34 years than older age groups (21). The possible explanation for this might be due to the worsening of the physiology of lungs parallel to aging lung and variability in how asthma responds to treatment as a result of differences in airway inflammation in aged people (34).
In this study, patients who reported to have lived in old houses were more likely to have uncontrolled asthma compared to those who have lived in houses constructed in the past 20 years. This result is supported by a study done in Poland (35), which demonstrated that there is a statistically significant difference with respect to asthma control between people who live in older houses and those who live in recently constructed houses. This might be because old houses increase dampness and facilitate mold growth that precipitates and worsen asthma symptoms resulting in uncontrolled asthma.
This study also demonstrated that the presence of pets within living houses was another determinant of uncontrolled asthma. Studies done in Congo and Morocco also reported a higher risk of uncontrolled asthma among patients who owned pets (11, 36). This could be due to an increment in asthma symptoms attributed to airway hyperresponsiveness, inflammation, and irritation of airways as a result of an allergy to the animals.
Another finding of this study was a significant association between uncontrolled asthma and comorbidity of rhinitis. This finding is in agreement with studies conducted in Brazil (36) and China (33). The study conducted in Brazil stated that asthmatic patients with symptoms of rhinitis were more than three times more likely to have uncontrolled asthma (36). Similarly, the Chinese study revealed that the risk of uncontrolled asthma was higher among patients with concomitant rhinitis (33). This might be due to the reason that allergic rhinitis is related to the worsening of asthma symptoms by enhancing the lower airway inflammation (37).
Having exacerbation in the last 12 months preceding the study was also found to increase the likelihood of having uncontrolled asthma attacks. The result of a study conducted in Addis Ababa; Ethiopia, was in line with this finding. The study showed that asthmatic patients who had exacerbation were more than two times more likely to develop uncontrolled asthma (22). The possible explanation could be due to the fact that past exacerbation predicts future exacerbation that might increase asthma symptoms (38). It might also be due to the effect of exacerbation on lung function i.e. accelerated loss of lung function as a result of asthma exacerbation (39).
This study also depicted that non-adherence to treatment was another determinant of uncontrolled asthma. This finding is in line with studies conducted in China (33), UK (40), North African and Middle East countries (41), Morocco (35), and Nigeria (18). A previous study conducted at Jimma Medical Center, Ethiopia, also showed that the odds of uncontrolled asthma was about 8.5 times higher among non-adherent patients when compared to the adherent ones (24). The possible explanation for this might be a rapid decline in lung function as a result of non-adherence to medications (42).
Lastly, patients who smoke cigarette were found to have a higher probability of uncontrolled asthma. This is supported by different studies conducted in Saudi Arabia (15), England (43), Hungary (44), and Nigeria (18). This might be because smoking is significantly associated with the decline in lung function (45). Another possible reason might be due to the fact that response to inhaled corticosteroids is attenuated among patients who smoke cigarette, hence, reduces the effectiveness of the drugs (46).
Limitation of the study
Even though the study tried to reduce the effect of the seasonality of asthma on its control through assessing the control over four weeks, it might not depict the distribution of uncontrolled asthma throughout the year. Self-report of some of the variables like behavioral variables (alcohol consumption, chewing khat, and smoking) and housing condition could introduce social desirability bias. Assessment of housing conditions based on self-response rather than expert evaluation might not depict the real standard of the housing.