Background: Rates of implantation of implantable cardioverter defibrillators (ICD) have increased continuously ever since they were first introduced. Notwithstanding guidelines endorsed by international scientific organizations, their use varies greatly across industrialized countries. The aim of this study was to assess whether variations in temporal trends and geographical distribution in the use of ICD devices across Piedmont, Northern Italy, are related to variations in need.
Methods: We calculated ICD implantation rates in the 19 local health units of Piedmont from 1999 to 2006, and correlated their temporal trend with four proxy indicators of need: coronary heart disease (CHD) mortality, CHD hospital discharge rates, cardiac heart failure discharge rates and bisoprolol or carvedilol prescription rates.
Results: The ICD implantation rate increased five-fold between 1999-2000 and 2005-2006, mainly among the elderly. Implantation rates were five-fold higher in men compared to women for the entire duration of the study. There were significant differences between local health units, which increased over time. Among men there was only a statistically significant correlation with coronary heart disease mortality (r = 0.66) in the period from 2005 to 2006, and with the use of bisoprolol and carvedilol starting from 2001 to 2002. No significant correlation with need indicators was found in women.
Conclusion: The use of ICD devices increased in apparent response to new research evidence, and, at least in part, in response to need. However, this process only involved men; ICD devices are largely underused in women and without apparent relation to need.