Subantimicrobial dose doxycycline effects on alveolar bone loss in post-menopausal women

Aim: Determine the efficacy of 2-year continuous subantimicrobial dose doxycycline (SDD; 20 mg bid) on alveolar bone in post-menopausal osteopenic, oestrogen-deficient women undergoing periodontal maintenance in a 2-year double-blind, placebo-controlled, randomized clinical trial. Material and Methods: One-hundred and twenty-eight subjects randomized to SDD or placebo (n=64 each). Posterior vertical bite wings taken at baseline, 1 and 2 years for alveolar bone density (ABD), using radiographic absorptiometry (RA) and computer-assisted densitometric image analysis (CADIA), and alveolar bone height (ABH). Statistical analyses utilized generalized estimating equations; primary analyses were intent to treat (ITT). Results are presented as SDD versus placebo. Results: Under ITT, there was no statistically significant effect of SDD on ABD loss (RA: p=0.8; CADIA: p=0.2) or ABH loss (p=0.2). Most sites (81-95%) were inactive. For subgroup analyses, mean CADIA was higher with SDD for non-smokers (p=0.05) and baseline probing depths >= 5 mm (p=0.003). SDD was associated with 29% lower odds of more progressive ABH loss in women > 5 years post-menopausal (p=0.05) and 36% lower among protocol-adherent subjects (p=0.03). Conclusions: In post-menopausal osteopenic women with periodontitis, SDD did not differ overall from placebo. Based on exploratory subgroup analyses, additional research is needed to determine the usefulness of SDD in non-smokers, subjects > 5 years post-menopausal and in deeper pockets.