Importance: The treatment of moderate to severe meibomian gland dysfunction (MGD) with oral doxycycline requires a 6-week course of treatment and has frequent adverse effects (AEs), which may be associated with poor compliance.
Objective: To determine if the AEs of a 3-week course of oral azithromycin were equivalent to the AEs of a 6-week course of oral doxycycline.
Design, setting, and participants: This double-masked randomized clinical trial was conducted at a referral center in Thailand from September 2018 to May 2022. Participants with moderate to severe MGD judged unresponsive to conservative management were included.
Interventions: Patients were randomized 1:1 to receive oral azithromycin (1 g once per week for 3 weeks) or oral doxycycline (200 mg daily for 6 weeks).
Main outcomes and measures: After initiating therapy, the study team assessed the total MGD score and Ocular Surface Disease Index (OSDI) score at the initial visit, at 6 weeks, and at 8 weeks, and assessed AEs at 6 weeks and 8 weeks. The prespecified equivalence margins for MGD score and OSDI score were set at ±2 and ±9, respectively.
Results: A total of 137 eyes from 137 patients were randomized into groups, 68 eyes in the azithromycin group and 69 eyes in the doxycycline group (female, 66.4%; mean age, 62.0 [SD, 15.1] years). The adjusted mean difference of total MGD scores between groups at week 6 and week 8 were -0.33 (95% CI, -1.70 to 1.03; P for equivalence = .01) and 0.13 (95% CI, -1.59 to 1.84; P for equivalence = .02), respectively. The adjusted mean difference of OSDI between groups score at week 6 and week 8 was -1.20 (95% CI, -5.31 to 2.91; P for equivalence < .001) and -1.59 (95% CI, -5.73 to 2.55; P for equivalence < .001), respectively. In addition, patients treated with azithromycin had fewer gastrointestinal AEs (4.4% vs 15.9%; risk difference, 11.5%; 95% CI 1.6%-21.4%; P = .03).
Conclusions and relevance: These data support an equivalency of effects of azithromycin as compared with doxycycline for MGD score and OSDI score at both follow-up times. The study did not show more gastrointestinal AEs in the azithromycin group. The reduced dosing and potentially fewer gastrointestinal AEs associated with azithromycin support its use as an alternative to doxycycline for at least 6 weeks.
Trial registration: ThaiClinicalTrials.org Identifier: TCTR20180810001.