Described are coating systems for the controlled delivery of hydrophilic bioactive agents, for example, from implantable medical devices. The coating systems of the invention comprise (a) a polymeric basecoat layer containing one or more hydrophilic bioactive agents; and (b) an elution-controlling topcoat layer that comprises a poly(ethylene-co-vinyl acetate) copolymer. The elution rate of the hydrophilic bioactive agent can be controlled by varying the vinyl acetate concentration in the elution-controlling topcoat layer.