Discussion
In sore throat patients, adjuvant dexamethasone resulted in a high proportion of patients reporting sufficient response. Additionally, of all the symptoms, cough was significantly negatively associated with treatment response. Patients presenting with less cough tended to experience higher sore throat resolution. There was no incidence of infection complications in patients. This new treatment strategy seems to be effective and safe.
The criteria for treatment outcome evaluation in the present study was different from those of other studies, as previous studies usually established clinical outcomes as complete resolution at 24 or 48 hours [17]. A recent randomized trial for elucidating the efficacy of dexamethasone without immediate antibiotic use showed that 22.6% and 35.4% of patients in the dexamethasone group experienced complete resolution at 24 and 48 hours, respectively, with a risk ratio (RR) of 1.28 at 24 hours and 1.31 at 48 hours [15]. A meta-analysis including both adults and children reported a RR of complete pain resolution of 3.2 at 24 hours and 14 % pain reduction by corticosteroids at 24 hours [14]. However, the criteria of clinical outcomes in this study was divided into three groups: non-responder, partial responder, and responder, because the study never aimed to compare the effects with or without steroid, but to describe the response according to the adjuvant steroid. Additionally, although only 2 (5%) of the patients in this study experienced complete resolution at 24 hours, 30 (75.0%) reported with an NRS of 2, 3, or 4 at 24 hours. Since a less than 4 NRS score generally indicates mild symptoms, the response in this study was enough to prove the efficacy of dexamethasone [18].
In the present study, cough was negatively associated with the response to corticosteroid treatment. After reviewing the symptoms in the medical record, patients with cough were stratified into two categories: those with intermittent cough, especially during sleep at night, and those with persistent cough, regardless of the specific condition. When we analyzed the treatment response according to the degree of cough, there was a significant difference in sore throat resolution between cough type. Although this result has not been evaluated in detail by other studies, we had a few hypotheses for the reason of the association between cough and treatment response. Several mechanisms are responsible for cough reflexes in the course of pharyngitis [19-21]. Corticosteroids suppress pro-inflammatory mediators, which could have decreased cough induced by these mediators [22]. However, steroid use might have been insufficient for the inhibition of persistent cough resulting from inflammation-induced nerve injury [23]. We believe that further studies can help elucidate this mechanism.
Because this study was retrospective, antibiotic use was decided by the clinician. Although several studies showed that most adults with sore throat do not need antibiotics, they are usually offered to adult sore throat patients [7]. Antibiotic use can reduce the incidence of suppurative complications and provide additional benefits to some patients with bacterial infections [24]. However, a recent study demonstrated that steroid use without immediate antibiotic use could improve sore throat symptom recovery [15]. Also, several studies have reported viruses as the cause of purulent or large tonsils in most patients [24,25]. The rapid streptococcal antigen test was unavailable at the primary clinics in which the present study was conducted and most of the included patients had a modified Centor score of 2 or 3. Therefore, almost all patients in this study were treated with immediate or delayed antibiotics due to the fear of bacterial tonsillitis. To reduce antibiotic use for sore throat, the evidence for adjuvant steroids should be collected continually and made widely known.
This study had several limitations. First, the small sample size could make its results less significant and might have prevented adverse event detection. However, we had 100% of the sore throat score data and collected information on variable symptoms, treatment options, and signs upon physical examination, to aid our search for prognostic factors by applying these variables to the multivariate model. Secondly, the included patients were all young men without comorbidity. There have been no studies that recruited patients with comorbidities [14,17]. Since corticosteroid-induced infection complications may be more common in patients with comorbidities, uncertainty remains about the prescribing of steroids to those presenting in primary clinics. Thus, future studies in patients with comorbidities are needed. Despite these limitations, the study has many strengths. To the best of our knowledge, this is the first study to evaluate the benefits of oral corticosteroids for Korean sore throat patients. We also analyzed the prognostic factor associated with treatment response, which could help in the selection of a target group of patients who would benefit from this treatment strategy, reducing unnecessary corticosteroid use.