A randomised controlled trial of the use of aciclovir and/or prednisolone for the early treatment of Bell's palsy: the BELLS study

F. M. Sullivan*, I. R. C. Swan, P. T. Donnan, J. M. Morrison, B. H. Smith, B. McKinstry, R. J. Davenport, L. D. Vale, J. E. Clarkson, R. Hernandez, K. Stewart, V. Hammersley, S. Hayavi, A. McAteer, D. Gray, F. Daly

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


Objective: To determine whether oral prednisolone or aciclovir, used separately or in combination, early in the course of Bell's palsy, improves the chances of recovery at 3 and 9 months.

Design: A 2 x 2 factorial randomised double-blind trial. Patients were randomly assigned to treatment by an automated telephone service using a permuted block randomisation technique with block sizes of four or eight, and no stratification.

Setting: Mainland Scotland, with referrals mainly from general practice to 17 hospital trial sites.

Participants: Adults (aged 16 years or older) with unilateral facial nerve weakness of no identifiable cause presenting to primary care, the emergency department or NHS24 within 72 hours of symptom onset.

Interventions: Patients were randomised to receive active preparations or placebo for 10 days: (I) prednisolone (50 mg per day, 2 x 25-mg capsules) and aciclovir (2000 mg per day, 5 x 400-mg capsules); (2) prednisolone and placebo (lactose, indistinguishable); (3) aciclovir and placebo; and (4) placebo and placebo.

Outcome measures: The primary outcome was recovery of facial function assessed by the House-Brackmann scale. Secondary outcomes included health status, pain, self-perceived appearance and cost-effectiveness.

Results: Final outcomes were available for 496 patients, balanced for gender; mean age 44 years; initial facial paralysis moderate to severe. One half of patients initiated treatment within 24 hours of onset of symptoms, one-third within 24-48 hours and the remainder within 48-72 hours. Of the completed patients, 357 had recovered by 3 months and 80 at 9 months, leaving 59 with a residual deficit. There were significant differences in complete recovery at 3 months between the prednisolone comparison groups (83.0% for prednisolone, 63.6% for no prednisolone, a difference of + 19.4%; 95% confidence interval (CI): + 11.7% to + 27.1%, p <0.001). The number needed to treat (NNT) in order to achieve one additional complete recovery was 6 (95% Cl: 4 to 9). There was no significant difference between the aciclovir comparison groups (71.2% for aciclovir and 75.7% for no aciclovir). Nine-month assessments of patients recovered were 94.4% for prednisolone compared with 81.6% for no prednisolone, a difference of + 12.8% (95% CI: + 7.2% to + 18.4%, p <0.001); the NNT was 8 (95% CI: 6 to 14). Proportions recovered at 9 months were 85.4% for aciclovir and 90.8% for no aciclovir, a difference of -5.3%. There was no significant prednisolone-aciclovir interaction at 3 months or at 9 months. Outcome differences by individual treatment (the four-arm model) showed significant differences. At 3 months the recovery rate was 86.3% in the prednisolone treatment group, 79.7% in the aciclovir-prednisolone group, 64.7% in the placebo group and 62.5% in the aciclovir group. At 9 months the recovery rates were respectively 96.1%, 92.7%, 85.3% and 78.1%. The increase in recovery rate conferred by the addition of prednisolone (both for prednisolone over placebo and for aciclovir-prednisolone over aciclovir) is highly statistically significant (p <0.001). There were no significant differences in secondary measures apart from Health Utilities Index Mark 3 (HUI3) at 9 months in those treated with prednisolone.

Conclusions: This study provided robust evidence to support the early use of oral prednisolone in Bell's palsy as an effective treatment which may be considered cost-effective. Treatment with aciclovir, either alone or with steroids, had no effect on outcome.

Original languageEnglish
Pages (from-to)1-154
Number of pages154
JournalHealth Technology Assessment
Issue number47
Publication statusPublished - Oct 2009


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