Abstract
Background
Incision and drainage (I&D) is the most common treatment for skin abscesses. A recent randomized clinical trial (RCT) of outpatients with limited (≤5 cm) skin abscesses demonstrated antibiotic therapy with clindamycin or trimethoprim-sulfamethoxazole (TMP-SMX) was superior to I&D alone. We performed a subgroup analysis to measure the effect of antibiotic duration and abscess size on clinical cure at 7–10 days after antibiotic completion.
Methods
Participants with complete data regarding adherence to the 10-day treatment were included. Demographic and baseline clinical features were compared using t-test, Pearson’s chi-square or Fisher’s exact test, or a non-parametric equivalent where appropriate. Largest abscess dimension (cm) was dichotomized by median size. The effect of antibiotic duration, abscess size (≤ median vs. >median) and covariates on clinical cure were measured using logistic regression. Breslow-Day Test for Homogeneity was used to assess the interaction between treatment and abscess size.
Results
Of 786 participants in the intention-to-treat analysis, complete adherence data were available for 680 (87%) participants. Of these, 463 (68%) received either antibiotic: 421 (91%) completed 10 days of therapy, 29 (6.3%) ≤7 days and 20 (4.3%) ≤5 days. Only antibiotic treatment duration was associated with clinical cure (table). Odds of clinical cure were 1.7 (95% CI: 1.5, 2.0) times higher for each additional day of treatment. Median abscess size was 2.5 cm (range: 0.2–5); 364 participants had abscesses ≤ median vs. 316 >median. Assessed continuously, abscess size was not associated with cure within antibiotic groups (table) or between placebo and treatment groups (OR 0.94, 95% CI: 0.58–1.5). Stratifying on size, no significant interaction was observed with antibiotic treatment (Breslow-Day P = 0.13).
Conclusion
Adherence to the treatment protocol was high. These data suggest that longer courses of antibiotic therapy in conjunction with I&D are associated with successful treatment of limited skin abscesses. Size was not associated with clinical cure. Prospective RCTs to determine the optimal length of treatment are needed.
Disclosures
All authors: No reported disclosures.
Session: 51. Soft Tissue and Skin Infections
Thursday, October 3, 2019: 12:15 PM