Efficacy of sub-antimicrobial dose doxycycline in post-menopausal women: clinical outcomes

Aims: To determine the clinical efficacy of a 2-year continuous sub-antimicrobial dose doxycycline (SDD; 20 mg bid) in post-menopausal, osteopenic, oestrogendeficient women on periodontal maintenance. Materials and Methods: One-hundred and twenty-eight subjects were randomized to SDD (n = 64) or placebo (n = 64). Clinical measurements were performed at posterior interproximal sites at baseline and every 6 months during this 2- year randomized, double-blind, placebo-controlled clinical trial with adjunctive, no-cost 3-4-month periodontal maintenance. Statistical analyses of secondary outcomes from this clinical trial used Generalized Estimating Equations in primarily intent-to-treat analyses. Results: For the placebo group, 3.4% of the sites showed improvement in clinical attachment levels (CAL) and 2.7% had progressive loss in CAL; for the SDD group, 5.0% of the sites showed an improvement in CAL and 2.2% had progressive loss in CAL. This difference (2.1% of sites) was more favourable in the SDD group than in the placebo [odds ratio (OR) 50.81%, 95% confidence interval (CI): 0.67-0.97, p = 0.03] in these well-maintained patients, whereas probing depths, bleeding on probing and supragingival plaque did not differ significantly between groups ( p > 0.2). However, in exploratory subgroup analysis of non-smokers, SDD showed reduced bleeding versus placebo (27% versus 33%; p = 0.05). In protocol-adherent subjects, the odds of bleeding were 34% lower for SDD (p = 0.05). Conclusions: Analyses of secondary outcomes of this clinical trial indicated that SDD may be of benefit in reducing progressive attachment loss in post- menopausal females; additional research is needed to confirm these findings.