Abstract
The Implanted Cardioverter Defibrillator (ICD) has emerged as one of the strongest therapeutic options for patients at high risk of SCD [65-67]. Despite this its high cost, in relation to other therapies, has made its use controversial in many patient groups. The repercussions are particularly visible in smaller countries like New Zealand where limited resources and doubts on cost effectiveness have resulted in lower implantation rates.
The aims of this Thesis were to provide an estimation of ICD cost effectiveness in a New Zealand context and label the strongest and weakest influencers of cost effectiveness. ICD costs and efficacy data, for Secondary prevention patients and Primary prevention patient with LV dysfunction, were collected through a review of international literature and analysis of New Zealand data collected from 2000-2007. These were then entered into a computer model and run over a twenty year lifetime. Model inputs included the efficacy of an ICD in secondary and primary prevention, measured through Life Years Gained, implant mortality, the cost of an ICD, costs of adverse events, lead/battery replacement costs and cost of annual follow up.
Results showed the average cost effectiveness of an ICD was NZ $107,191/ LYG, when used in secondary prevention and $178,291/ LYG in primary prevention. The overall range of cost effectiveness across all model inputs was $85,799/ LYG to $207,301/LYG. The strongest factors influencing cost effectiveness were efficacy of the device in both groups, the cost of battery replacements, longevity of ICD leads, mortality rate of primary prevention patients and the annual cost of follow up. The weakest influencers of cost effectiveness included the costs of initial ICD and implant procedure and the cost of adverse events occurring from ICDs. These findings correlated well with previous studies conducted overseas.
New Zealand showed a similar range of cost effectiveness, when compared to international trials. Our estimate remained outside the range of cost effectiveness thresholds considered economically attractive however when assessed alongside other therapies was comparative to renal dialysis for end stage disease. The results of this thesis encourage an increase in implantation rates to match other Westernised countries and detail areas that need to be addressed to further improve cost effectiveness.