Extensive research and clinical emphasis has been placed on evaluation of the impact of severe asthma on patients and healthcare systems, with new biologic treatments in development specifically to address the unmet needs of these patients [3, 25]. Patients with mild asthma defined by GINA Steps 1 or 2 are generally expected to have good or complete control of symptoms and have a low risk for exacerbations.
Our results indicate similarities between physician and patient evaluations of asthma control. Only 2.9% of patients overall considered themselves poorly controlled, while 3.5% of Step 1 patients and 7.1% of Step 2 patients were considered poorly controlled by their physicians. However, a relatively large proportion of patients were not well controlled according to the ACT, a validated, objective assessment of asthma control.
Other assessments of asthma symptoms and exacerbations included overall patient-reported occurrence of nocturnal symptoms (40.6%), one or more significant worsening of symptoms in the last 4 weeks (10.5%), and rescue inhaler usage more than twice per week (9.7%). Further, assessment of asthma control revealed that approximately 25% of patients fell below the threshold of 20 on the ACT, which is considered an indication of poorly-controlled asthma. Other research incorporating objective assessments of asthma control and risk for exacerbations reveals that a significant proportion of patients with mild asthma are symptomatic, experience exacerbations, and are not well controlled [9, 11, 13].
For example, an observational, cross-sectional, community-based study evaluated the level of control in 950 adult patients with mild asthma who were regularly treated by general practitioners, with more than 80% prescribed ICS . Of these, only 13.7% were considered totally controlled (ACT score of 25), 51.0% well controlled (ACT score of 20–24), and 35.3% were classified as not well controlled or poorly controlled (ACT score ≤19) . Patients with poorly-controlled asthma were at significantly greater risk for asthma-related unscheduled visits to specialists, ED, and hospital admissions .
Research suggests many patients perceive their asthma as controlled and not serious despite the occurrence of symptoms and exacerbations [26–28]. It has been suggested that patients with mild disease may accept their symptoms and have lower adherence to preventive therapy, possibly due to a lack of understanding that therapy will control current symptoms and reduce the risk of future disease progression [13, 28].
Frequency of rescue inhaler usage, although subject to variability, can be a useful proxy for asthma control. Patients may use as-needed relievers frequently but consider themselves well controlled because rescue therapy prevents their symptom escalation. However, clinicians perceive the use of rescue therapy as an indicator of poor asthma control. Our results show less frequent use of rescue inhalers was associated with better control characterized by higher ACT scores. This suggests that accurate information about the frequency of rescue inhaler usage can be a useful proxy to assess control in the absence of reported symptoms. One or more exacerbations in the preceding 12 months was reported by 19% of mild asthma patients overall experienced. This suggests that approximately one in five patients with mild asthma might benefit from treatment intensification . These results are consistent with those reported from an earlier Respiratory DSP survey  and highlight the persistence of unmet needs for a significant proportion of mild asthma patients.
Approximately half of patients were employed full-time and about 20% were full-time students. While the mean level of absenteeism was low, the mean impact of asthma on productivity, overall work impairment, and activity impairment ranged from 12% to 16%. This provides an indication of the indirect economic costs and restrictions on patient’s ability to perform normal daily activities due to mild asthma. GINA Step 1 patients reported less work-related impairments compared to those classified as GINA Step 2, suggesting higher indirect costs and greater disease burden for Step 2 patients.
Low adherence was evident for approximately a third of patients in this survey. Further, a substantial proportion of patients were considered by their physician to underestimate the seriousness of their condition (data not shown). This is consistent with findings from an international survey of more than 10,000 asthma patients, which found that self-reported classification of symptom control was not aligned with guideline-based classification of control . These findings may reflect low patient concern about their condition, placing them at increased risk for future worsening of their disease.
It is conceivable that patients are unaware of the distinction between poor and good asthma control and may not understand how their symptoms could be better controlled with appropriate medical therapy. 64.4% of GINA Step 2 patients were classified as of medium or high adherence. This is slightly higher than adherence rates reported in other studies, which estimate that 50% of patients diagnosed with mild, moderate, and severe asthma adhered to their treatment regimen,  but is dependent on the measurement of adherence. Improved adherence may be achieved through implementation and ongoing review of asthma action plans and ongoing patient education regarding the importance of adherence and is recommended by treatment guidelines for patients with asthma of all degrees of severity [2, 32].
Written personalized asthma action plans are considered an essential component of a self-management program for people with asthma [32, 33]. An evidence-based review found that individualized written plans were associated with decreases in hospital admissions, ED visits, unscheduled outpatient appointments and improvements in markers of asthma control and patient quality of life [32, 34]. While we did not collect information about asthma action plans in this survey, patients with action plans were not excluded from participation. Future surveys will include questions to assess whether patients have asthma action plans and any associations between such plans, treatment modifications, and the management of mild asthma.
Patients included in the Respiratory DSP sample were not a true random sample, since study methods specified inclusion of five consecutive patients who consulted their physician and met study eligibility criteria. However, prospective consecutive sampling does limit bias that might be attributable to pre-selection of patients by the physician.
Our findings are representative of patients consulting a primary care physician or specialist for routine care, which may limit generalizability to the general population of mild asthmatics. There is the possibility of differences between patients who agreed to complete the survey and those who declined.
The diagnosis of asthma was confirmed by physicians and dependent on their diagnostic skills. However, this is a common and well-accepted method for the identification and recruitment of samples in real-world research. More than one-half of patients overall did not have results for pre-bronchodilation FEV1% and 66.3% of all patients had missing results for post-bronchodilation FEV1% data, with similar proportions of missing data for Step 1 and 2 patients. This is consistent with general clinical practice where it has been reported that spirometry is infrequently used to assess asthma control and treatment effectiveness in community-dwelling patients with asthma [35–37].
Data on asthma symptoms were not collected at a universally-recognized allergy season, which was not possible given the number of countries and variations between countries in the timing of the allergy season. Therefore, the burden related to asthma symptoms described here could be an underestimation compared with the asthma burden associated with allergy season.
The quality of the data depended on accurate reporting by physicians and patients. Physicians were permitted to refer to patient records, which was intended to reduce errors in reporting treatment, clinical events and comorbidities. The majority of patient questions focused on current or recent circumstances, which helped reduce recall bias.
Physician inclusion in our study was potentially influenced by their willingness to participate. We imposed minimal eligibility criteria associated with the number of asthma patients seen and active involvement in the management of asthma patients. Thus, physicians were likely to be representative of the general population of clinicians caring for patients with asthma.