"Trachoma is the leading infectious cause of blindness worldwide, and trichiasis, a chronic sequela of trachoma, plays a major role in trachoma-associated vision loss. Better strategies are needed to prevent recurrence of trachomatous trichiasis after surgery because even in the best of circumstances, recurrence affects nearly one in six patients while the rate has been reported to be as high as 80% in some series," Dr. West told Ophthalmology Times.
"Single-dose oral azithromycin is a simple, convenient, safe, and well-tolerated intervention that eliminates compliance as a concern, and in many developing countries, it is provided free through a donation program. Based on those features and the outcome of our study, we believe that in trachoma-endemic areas, a single dose of azithromycin should be provided to patients immediately after trichiasis surgery in order to reduce the risk of recurrence," she said.
Dr. West is the El Maghraby Professor of Preventive Ophthalmology, Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore. The study was conducted by Dr. West and colleagues from Johns Hopkins along with physicians from ORBIS International. It was published in the March issue of Archives of Ophthalmology [2006;124:309-314].
Ethiopia was selected as the site for this study in part because of the high prevalence of trachoma and trichiasis in that country.
"Ethiopia was a logical choice because we expected we would be able to complete enrollment quickly, but also because there is a national trachoma program in place so we knew that recommendations derived from our study could be implemented," she explained.
The trial enrolled 1,452 adult patients who had no previous surgery for trichiasis in the study eye. They underwent surgery performed by integrated eye-care workers (IECWs) trained through the ORBIS International program. The patients were randomly assigned equally into three groups for postoperative treatment. In two arms, the surgical patient only was treated and received either a single 1-g oral dose of azithromycin or topical tetracycline twice daily for 6 weeks. In the third group, a single oral dose of azithromycin was given to both the patient (1 g) and all household members (20 mg/kg up to 1 g).
Recurrence of trichiasis was defined as presence of a lash touching the globe or evidence of epilation. During 1 year of follow-up after surgery, the recurrence rate of trichiasis in the combined azithromycin treatment arms was 6.9 per 100 person-years, which was about one-third lower than the rate of 10.3 per 100 person-years observed in the tetracycline-treated group (p = 0.047). In a multivariate model adjusting for other predictors of recurrence, azithromycin maintained its benefit for significantly reducing the risk of recurrence by about one-third.
The recurrence rate was not statistically different in the group where patients and household members were treated compared with the arm where only the patients received azithromycin, 5.8 versus 8.1 per 100 person-years.
"Re-exposure to the infectious agent has been proposed as a contributing factor to trachomatous trichiasis recurrence. Treatment of household members in addition to the surgical patient was included in this study to evaluate whether it might be a way to reduce re-exposure and recurrence risk. However, in this study we found no added benefit," Dr. West explained.
About 19% of the enrolled patients were found to be infected with Chlamydia trachomatis at the time of surgery. In all treatment groups, the incidence of infection was significantly reduced when assessed at 1.5 months after surgery and again at the end of follow-up. Presence of C trachomatis infection after surgery was not a significant risk factor for recurrent trichiasis, however.
"Those results must be interpreted carefully considering the difficulty of obtaining a good specimen for laboratory assessment from these eyes with their scarred lids. Furthermore, we only obtained a specimen for C trachomatis assessment at two time points after surgery. Therefore, we cannot rule out the possibility that infections occurred sporadically during the interim periods," Dr. West said.