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Are antibiotics beneficial for patients with sinusitis complaints?

Background: Sinusitis is a common diagnosis for which antibiotics are prescribed in the outpatient setting. Although, there is a lack of epidemiological evidence as to which patients should receive antibiotics and which patients have a viral infection.

Objective: The purpose of the study was to determine the type of patient who should receive antibiotics for treatment of sinusitis.

Methods: This was a randomized, double-blind, placebo controlled study. All patients were recruited from a primary care office in a suburb of Washington D.C. Two physicians and one nurse practitioner enrolled and treated all patients over an 18 month period from Oct 2001 to March 2003. Inclusion criteria included; 18 years or older, at least one cardinal feature described by the clinical prediction rule (1. purulent nasal discharge predominating on one side 2. local facial pain predominating on one side 3. purulent nasal discharge on both sides 4. pus in the nasal cavity and had symptoms for at least 7 days.) Exclusion criteria included: antibiotic use in the past month, allergy to penicillin, sinus surgery, compromised immunity, pneumonia or streptococcal pharyngitis. A total number of 135 patients underwent randomization: 67 were assigned to receive amoxicillin 1000mg twice daily and 68 to receive matching placebo for 10 days. Trained personnel, masked to treatment assignment, conducted follow-up telephone interviews on study days 3, 7, and 14 to assess clinical improvement. Twelve follow-up questions were asked. The primary outcome measure was “improved” versus “not improved”. Secondary outcome measures included: time to improvement, patient’s self-rating of sickness at the end of 2 weeks, and to evaluate the clinical prediction rule previously described. A power of 80% was reported for the primary outcome measure but was not reported for the secondary analyses. All primary analyses were conducted on an intention-to-treat basis. Investigators used the chi-square test, Kaplan-Meier method, Wilcoxin test, Cox Proportional Hazards regression, a univariate repeated measures ANOVA and analysis of covariance to evaluate outcome measures.

Results: Analyses showed that 32 (48%) patients in the amoxicillin group compared to 25 (37%) in the placebo group (p=0.26) showed complete improvement by the end of the two week follow-up period (RR=1.3 95%CI, 0.87-1.94). Compared to the placebo group, the amoxicillin group improved earlier in the course of treatment, a median of 8 vs 12 days (p=0.039). The mean Likert scores with 1 being best condition and 10 being worst condition, when patients were asked “how sick do you feel today?” decreased from 6.1(day 0) to 2.3(day 14) and 6.3(day 0) to 2.8(day 14) in the amoxicillin and placebo groups, respectively. The results in this study were unable to validate the clinical prediction rule to determine which patients should receive antibiotic therapy for sinusitis. No patients dropped out due to adverse effects. The majority of adverse effects were related to gastrointestinal problems. The authors concluded that with respect to the patient-oriented outcome of clinical improvement, amoxicillin provided no significant benefit over placebo. The author’s also stated that the data suggested that there is a subgroup of patients who were given antibiotics and showed clinical improvement at a much quicker rate.

Strengths: This was a prospective, randomized, placebo-controlled study in a peer-reviewed journal. The subjects, practitioners and evaluators were blinded to treatment assignment.

Weaknesses: The patients were followed via telephone to assess clinical improvement and this may not have been reflective of objective results. The authors did not address the issue of compliance with treatment regimen. Nineteen patients were lost to follow-up and counted as “not improved” in the analyses, although it is not known if these patients were truly not improved. Amoxicillin may not have been appropriate for all patients, depending on prior antibiotic exposure and frequency of sinusitis, which was not addressed. The clinical prediction rule used by the authors was faulty (two signs/symptoms were not mutually exclusive). Secondary analyses contained two few people to determine actual significance of results. The authors stated non significance for some analyses but did not report p values. The patients were followed for 14 days, however this may not have been a long enough time period. Patients that had not improved by the end of 14 days were counted as “not improved” in the analyses. There was a gap of one week between the last two time frames of which patients were contacted for follow-up analyses, which may lead to unreliable self-reported outcomes. The first page of the article contained a misleading practice recommendation of “A” meaning recommendation based on consistent, good quality, patient-oriented evidence, which is not the case with this study. The outcome measure of “improved” versus “not improved” can be unreliable because it is based on subjective evaluation.

Conclusion: The authors reported no significant differences between amoxicillin and placebo when evaluating complete improvement, but in the patients who did show improvement, patients improved significantly earlier when given amoxicillin. Due to weakness in the study, it would be difficult to generalize these results to the general patient population with sinusitis. I agree with the authors in stating that additional clinically oriented studies need to be conducted to address the issue of clarifying which patients would benefit from antibiotic therapy in sinusitis.

Merenstein D, Whittaker C, Chadwell T, Wegner B and D’Amico F. Are antibiotics beneficial for patients with sinusitis complaints? J Fam Pratc;54(2):144-151.

Kolleen Koast, Pharm D. Candidate