Clinical implications of the association between fluoroquinolones and tendon rupture: The magnitude of the effect with and without corticosteroids.

Aims: To estimate the relative, absolute and attributable risk of non-traumatic tendon rupture, at various sites, associated with use of fluoroquinolones, with and without concomitant corticosteroids.
Methods: We conducted cohort and nested case-control studies among fluoroquinolone users in the United Kingdom Clinical Practice Research Datalink Gold. We estimated the excess risk (cohort analysis) and odds ratios (ORs) (case control) of tendon rupture by fluoroquinolone (current, recent and past use versus unexposed) and corticosteroid (current versus unexposed) use.
Results: Among 740 926 patients with a fluoroquinolone prescription, 3957 cases of tendon rupture were identified. The excess risk due to current fluoroquinolone use was low: any tendon rupture 3.73 (95% confidence interval, CI, 2.08-5.39) per 10 000 person-years (PY) and Achilles tendon rupture 2.91 (1.71-4.11) per 10 000 PY. The excess risk of any tendon rupture was much higher for current concomitant fluoroquinolone and corticosteroid use versus corticosteroids alone: 21.2 (11.3-31.2) per 10 000 PY. In the case-control, OR (95% CI) among current fluoroquinolone users versus unexposed patients was elevated: any tendon rupture 1.60 (1.22-2.09), Achilles tendon 2.71 (1.76-4.17) and bicep tendon 1.53 (0.85-2.73). The risk of any tendon rupture was higher among women (OR 2.27 [1.54-3.34]), patients aged 60+ (OR 2.42 [1.74-3.37]), and concomitant corticosteroid use (OR 6.64 [3.99-11.1]).
Conclusions: Fluoroquinolones increase the risk of Achilles tendon rupture and, to a lesser extent, bicep tendon rupture, but the attributable risk is low. The risk is materially increased with concomitant use of corticosteroids.
(© 2019 The British Pharmacological Society.)