Level 1: Likely reliable evidence
A randomized trial evaluated 133 women with mild pelvic inflammatory disease (PID). They were treated with ceftriaxone 250 mg IM and then randomized to azithromycin 1 g orally once weekly for two weeks vs. doxycycline 200 mg once daily for 14 days (test dose 200 mg once given on days 1 and 8, then 100 mg twice daily on days 2-7 and 9-14) (Obstet Gynecol. 2007;110:53-60). Thirteen patients were excluded due to diagnosis other than PID; 11 patients lost to follow-up were counted as treatment failures.
Comparing azithromycin vs. doxycycline, the doxycycline group had more patients lost to follow-up (6.5% vs. 12.1%). The cure rates were 90.3% vs. 72.4% in intention-to-treat analysis (P=.01, NNT 6), 98.2% vs. 85.7% in per-protocol analysis with 106 patients (P=.02, NNT 8), and 66.6% vs. 53.1% in a subgroup of 74 women with endometritis confirmed on initial biopsy (NNT 8).