Estimation of the clinical and economic consequences of non-compliance with antimicrobial treatment of canine skin infections.

The goal of this study was to estimate the health and economic consequences of non-compliance with oral antimicrobial treatment in dogs with superficial pyoderma, wounds or abscesses in the US. A mathematical model (Markov model) which simulated treatment with long-term injectable cefovecin versus oral amoxicillin/clavulanic acid was developed and accounted for the effect of non-compliance on clinical outcomes and mean total treatment costs per patient. Efficacy parameters considered in the model were derived from clinical studies. Treatment failure due to oral antimicrobial treatment non-compliance was approximated from published data at 13.6%. US cost data for 2009 were derived from public sources. When non-compliance was considered as a cause of treatment failure with oral medication, the long-term injectable antibiotic was more effective than oral comparator (162 versus 158 days without clinical signs). Mean total treatment costs were lower with cefovecin (USD 376.74) versus amoxicillin/clavulanic acid (USD 382.34) in dogs of 25 kg; and cefovecin remained cost-saving up to a body weight of 31 kg. In large dogs, cefovecin was more costly; however, total therapy costs were less than 6% greater than with amoxicillin/clavulanic acid. Accordingly the higher drug and administration costs of the long-term injectable antibiotic were totally or substantially offset when non-compliance was considered as reason for treatment failure with oral medication. The model also allowed for the estimation of the impact of various non-compliance scenarios.