  The decay of the K+K- hadronic atom kaonium is investigated
non-perturbatively using meson-meson interaction amplitudes taken from leading
order chiral perturbation theory in an approach adapted from that proposed by
Oller and Oset [18]. The Kudryavtsev-Popov eigenvalue equation is solved
numerically for the energy shift and decay width due to strong interactions in
the 1s state. These calculations introduce a cutoff ~ 1.4 GeV in O(4) momentum
space that is necessary to regulate divergent loop contributions to the
meson-meson scattering amplitudes in the strong-interaction sector. One finds
lifetimes of 2.2 \pm 0.9 x 10-18s for the ground state of kaonium.
