In our systematic review of measures of outcome for patients with sinusitis, we identified 3 HRQL instruments that have acceptable performance characteristics for patients with chronic sinusitis. The responsiveness of these instruments appears adequate in surgically treated patients, but may be inadequate for patients treated medically. For patients with acute sinusitis, no measure of outcome has met even minimal validation requirements. Finally, no performance characteristics have been determined for any measure of outcome for use in nonspecialty, primary care settings.
A lack of validated measures of outcome for acute sinusitis may limit current treatment recommendations. Two recent meta-analyses of antibiotic use for patients with acute sinusitis found a marginal benefit to antibiotics.6,51
The 5 placebo-controlled studies included in these meta-analyses used heterogeneous outcome measures that included a 4-point system combining x-ray evaluation and patient information,52
a 3-point global clinical rating,53
a 5-point patient self-assessment,54
the absence of symptoms at 2 weeks,55
or use of the McGill-Melzack Pain Questionnaire.56
None of the measures reported in these studies have been validated for use in patients with acute sinusitis. Because the measures of outcome are unvalidated, antibiotics for acute sinusitis may actually be more or less effective than previously reported.
Given the subjective nature of outcomes for patients with sinusitis, it is possible that the marginal benefit identified with antibiotics is due to the use of measures with poor responsiveness. Antibiotics for acute sinusitis could be more effective than previously reported if outcome measures that were more responsive to change were available.
Virtually all patients with acute sinusitis would be expected to return to their baseline status within a relatively short period of time, approximately 2 weeks.57
If a measure of outcome cannot detect such rapid changes in clinical status, then important differences between treatment groups could be missed when such differences truly exist. Several of the placebo-controlled trials of antibiotics for acute sinusitis used outcome assessment at a single point in time. Such cross sectional assessment may fail to detect divergence between groups occurring at points between baseline and follow-up, giving false-negative results.
Conversely, antibiotics for acute sinusitis may be less effective than previously reported. For example, the unvalidated sinusitis symptom scores that have been used may be too narrow in scope. If sinusitis-specific symptoms improve, but not to the point where a patient is able to return to work, or if more general symptoms persist (e.g., fatigue), a symptom score would show improvement where a HRQL measure would not. Similarly, if a patient's symptoms resolve, but the patient is unable to return to work for a treatment-related reason (e.g., diarrhea from antibiotics), again, a symptom score would show improvement where a HRQL measure would not. Use of a simple symptom score might bias results in favor of treatment.
This review has several limitations that should be acknowledged. There is no standard instrument to assess the quality of studies that evaluate subjective patient-reported outcome measures. We used a series of 10 questions proposed by Gill and Feinstein to evaluate the rigor with which quality of life was defined and assessed in each study.17
By this metric, we found that studies evaluating sinusitis measures were of generally low quality. These low scores may reflect the original authors' lack of familiarity with quality of life or HRQL as outcome measures. Additionally, most of the articles examined were primarily focused on evaluating a procedure or treatment rather than quality of life itself. Additionally, some authors may have believed that symptoms rather than HRQL are the preeminent outcome in patients with sinusitis. However, Witsell et al.,28
using the Short Form-12, show that patients with acute sinusitis have measurable decrements in HRQL, arguing that even a simple, generic HRQL measure can detect changes in health status for patients with acute sinusitis.
For conditions like acute sinusitis that lack convenient objective clinical measures of outcome, there is a need for patient-reported subjective measures that integrate symptoms and their impact on HRQL. Such a measure of outcome should be valid, reliable, and have excellent responsiveness to change characteristics. The results of such a measure should be interpretable, so that changes observed by researchers and clinicians can be used to inform patients about the expected magnitude of impact of a proposed therapeutic intervention. Studies validating such a measure of outcome for adults with acute sinusitis should be performed in a variety of settings, including primary care, with well-defined patient populations. Only with a validated, interpretable measure of outcome for patients with acute sinusitis can well-founded conclusions be made about the efficacy of specific treatments.