Acute rhinosinusitis (ARS) is a common disease associated with significant morbidity, lost time from work and treatment costs. Considering the public health threat posed by increasing antibiotic resistance, strong evidence of symptom relief is needed to justify prescribing antibiotics for this usually self-limiting disease. 

Placebo-controlled clinical trials to evaluate antibiotic treatment have had conflicting results, likely due to differences in diagnostic criteria and outcome assessment. Studies requiring confirmatory tests such as sinus radiography have tended to show treatment benefit, but meta-analyses of these studies have generally concluded that clinical benefit with antibiotic treatment was small due to the high rate of spontaneous improvement (approximately 69%). 

Studies using clinical diagnostic criteria tend to show no or minimal treatment benefit and higher spontaneous resolution (approximately 80%). Despite the controversy regarding their clinical benefit and concerns about resistance, antibiotics for sinusitis account for one in five antibiotic prescriptions for adults in the US.

The object of the study¹ was to determine the incremental effect of amoxicillin treatment over symptomatic treatments for adults with clinically diagnosed ARS.

The study was a randomised, placebo-controlled trial of adults with uncomplicated ARS who were recruited from 10 community practices in Missouri, US, between November 1, 2006, and May 1, 2009. 

Patients were given a 10-day course of either amoxicillin (1,500mg/d) or placebo administered in three doses per day. All patients received a five-to-seven day supply of symptomatic treatments for pain, fever, cough and nasal congestion to use as needed. 

The primary outcome was improvement in disease-specific quality of life after three to four days of treatment assessed with the Sinonasal Outcome Test-16 (SNOT) minimally important difference of 0.5 units on a 0-3 scale. Secondary outcomes included the patient’s retrospective assessment of change in sinus symptoms and functional status, recurrence or relapse, and satisfaction with and adverse effects of treatment. Outcomes were assessed by telephone interview at days three, seven, 10 and 28. 

A total of 166 adults (36% male; 78% with white race) were randomised to amoxicillin (n = 85) or placebo (n = 81); 92% concurrently used one or more symptomatic treatments (94% for amoxicillin group versus 90% for control group; p = 0.34). 

The mean change in SNOT scores was not significantly different between groups on:

• Day three – decrease of 0.59 in the amoxicillin group and 0.54 in the control group; mean difference between groups of 0.03 [95% CI, -0.12-0.19]
• And day 10 – mean difference between groups of 0.01 [95% CI, -0.13-0.15]. 
• However, it differed at day seven favouring amoxicillin:
• Mean difference between groups of 0.19 [95% CI, 0.024-0.35]. 
• There was no statistically significant difference in reported symptom improvement at:
• Day three – 37% for amoxicillin group versus 34% for control group; p = 0.67
• Or at day 10 – 78% versus 80%, respectively; p = 0.71.
• Whereas at day seven:
• More participants treated with amoxicillin reported symptom improvement – 74% versus 56%, respectively; p = 0.02. 

No between-group differences were found for any other secondary outcomes. No serious adverse events occurred. 

The authors conclude that a 10-day course of amoxicillin compared with placebo did not reduce symptoms at day three of treatment in ARS.

Reference

1. Garbutt JM, Bannister C, Spitznagel E, Piccirillo JF, JAMA 2012; 307(7): 685-692