Clinical and cost-effectiveness of spironolactone in treating persistent facial acne in women: SAFA double-blinded RCT.

Background

Acne is common, can cause significant impact on quality of life and is a frequent reason for long-term antibiotic use. Spironolactone has been prescribed for acne in women for many years, but robust evidence is lacking.

Objective

To evaluate whether spironolactone is clinically effective and cost-effective in treating acne in women.

Design

Pragmatic, parallel, double-blind, randomised superiority trial.

Setting

Primary and secondary healthcare and community settings (community and social media advertising).

Participants

Women aged 18 years and older with facial acne persisting for at least 6 months, judged to potentially warrant oral antibiotic treatment.

Interventions

Participants were randomised 1 : 1, using an independent web-based procedure, to either 50 mg/day spironolactone or matched placebo until week 6, increasing to 100 mg/day spironolactone or matched placebo until week 24. Participants continued usual topical treatment.

Main outcome measures

Primary outcome was the adjusted mean difference in Acne-Specific Quality of Life symptom subscale score at 12 weeks. Secondary outcomes included Acne-Specific Quality of Life total and subscales; participant self-assessed improvement; Investigator's Global Assessment; Participant's Global Assessment; satisfaction; adverse effects and cost-effectiveness.

Results

Of 1267 women assessed for eligibility, 410 were randomised (201 intervention, 209 control), 342 in the primary analysis (176 intervention, 166 control). Mean age was 29.2 years (standard deviation 7.2) and 7.9% (28/356) were from non-white backgrounds. At baseline, Investigator's Global Assessment classified acne as mild in 46%, moderate in 40% and severe in 13%. At baseline, 82.9% were using topical treatments. Over 95% of participants in both groups tolerated the treatment and increased their dose. Mean baseline Acne-Specific Quality of Life symptom subscale was 13.0 (standard deviation 4.7) across both groups. Mean scores at week 12 were 19.2 (standard deviation 6.1) for spironolactone and 17.8 (standard deviation 5.6) for placebo [difference favouring spironolactone 1.27 (95% confidence interval 0.07 to 2.46) adjusting for baseline variables]. Mean scores at week 24 were 21.2 (standard deviation 5.9) in spironolactone group and 17.4 (standard deviation 5.8) in placebo group [adjusted difference 3.77 (95% confidence interval 2.50 to 5.03) adjusted]. Secondary outcomes also favoured spironolactone at 12 weeks with greater differences at 24 weeks. Participants taking spironolactone were more likely than those taking placebo to report overall acne improvement at 12 weeks {72.2% vs. 67.9% [adjusted odds ratio 1.16 (95% confidence interval 0.70 to 1.91)]} and at 24 weeks {81.9% vs. 63.3% [adjusted odds ratio 2.72 (95% confidence interval 1.50 to 4.93)]}. Investigator's Global Assessment was judged successful at week 12 for 31/201 (18.5%) taking spironolactone and 9/209 (5.6%) taking placebo [adjusted odds ratio 5.18 (95% confidence interval 2.18 to 12.28)]. Satisfaction with treatment improved in 70.6% of participants taking spironolactone compared with 43.1% taking placebo [adjusted odds ratio 3.12 (95% confidence interval 1.80 to 5.41)]. Adverse reactions were similar between groups, but headaches were reported more commonly on spironolactone (20.4% vs. 12.0%). No serious adverse reactions were reported. Taking account for missing data through multiple imputation gave an incremental cost per quality-adjusted life-year of £27,879 (adjusted) compared to placebo or £2683 per quality-adjusted life-year compared to oral antibiotics.

Conclusions

Spironolactone resulted in better participant-reported and investigator-reported outcomes than placebo, with greater differences at week 24 than week 12.

Trial registration

This trial is registered as ISRCTN12892056 and EudraCT (2018-003630-33).

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 16/13/02) and is published in full in

Acne (or spots) is common and often persists into adulthood. Many people take long courses of antibiotic tablets, but concerns about antibiotic resistance mean alternatives are needed. Spironolactone is a medicine that is sometimes used for acne in women. However, we do not know whether it works. This trial aimed to answer this question. We invited women aged over 18 who had acne on their face for at least 6 months to take part via their general practitioner surgery, hospital or advertising. Women were randomly assigned to two groups: one group was given spironolactone and the other group was given identical-looking placebo (‘dummy pill’) daily for 24 weeks. Women in both groups could continue using acne treatments applied to the skin (gels/creams/lotions). We asked participants to rate their acne using a questionnaire called Acne-Specific Quality of Life, asked whether they felt their skin had improved and asked skin specialists to assess their skin. Four hundred and ten women took part, many of whom had had acne for a long time. Acne-Specific Quality of Life scores improved in both groups by 12 weeks but improved more in the spironolactone group at 12 and 24 weeks. When asked directly whether their skin had improved, 71% of participants in the spironolactone group said it had, compared with 43% on placebo. Skin specialists were also more likely to report that the acne had improved in the spironolactone group. Side effects were mild and similar in both groups but there were slightly more headaches on spironolactone (20% compared with 12%). Spironolactone is likely to represent value for money for the National Health Service, though this depends on a number of factors including what it is compared to. This trial suggests that spironolactone is a useful additional treatment for women with persistent acne.