4.2 Study limitations
The findings of this study have to be seen in light of some limitations.
The first is the variable length of treatment for each patient.
Depending on the referral pathway, patients may have presented at a
various stage of the clinical course of disease. In addition, each case
received a different treatment regimen before referral. The diversity of
interventions used in general practices has been previously reflected in
data provided by the General Practice Research Database (GPRD) (4) and
it has been demonstrated in our data (Chart 1).
The second limitation concerns recording of possible side effects of
fluticasone propionate. Although we did not systematically ask for side
effects in our follow ups, none of our patients raised any concerns. The
systemic bioavailability at 2400μg daily dose is estimated to be very
low (0.06%). (11) Given the fact that fluticasone propionate was
prescribed topically to the skin, not mucosa, the systemic
bioavailability is likely to be lower than the figure cited above.
Hence, it can be concluded that fluticasone propionate is likely to
produce very small systemic exposures to steroids, and have a low
potential for systemic side effects when administered topically to ears
at 200μg daily dose. The last limitation is the restricted number of
patients and those lost to follow up. It may be argued that the small
sample size may over-estimate the magnitude of the association observed.
While recognising the limitations to our project, we believe that
fluticasone propionate offers promise within a domain notoriously
difficult to treat. There is no specific advice in guidelines regarding
the choice of corticosteroids in chronic cases of otitis externa. (1,9)
Also, the literature review reveals no previous study that has assessed
the effectiveness of fluticasone propionate, or any other
corticosteroid, for treatment of COE. In any future study, a larger
sample size will be required, along with a recording of detailed
clinical features including any concurrent disease modalities, side
effects and social factors. Considering the size of the problem (7,8),
we believe the clinical practice in the field of otolaryngology will
benefit from a prospective study that allows randomized head-to-head
comparison for efficacy and safety of fluticasone propionate, in chronic
cases of otitis externa.
Conclusion
Chronic otitis externa is often a recalcitrant problem and a challenge
for the attending doctor. In the absence of guideline recommendations
regarding the choice of corticosteroids for chronic otitis externa, we
present a case-series demonstrating the potential benefit of fluticasone
propionate. All patients (20/20) who returned to the follow up showed
resolution of symptoms, having previously failed with a multitude of
conventional management options. We did have some limitations which we
hope could be analysed further with a more robustly designed study,
however the use of Flixonase® is an exciting and
potentially important tool in the arsenal of the otolaryngologist.