Determinants of geographic variations in pacemakers and implantable cardioverter defibrillators implantation rates.

Despite the established therapeutic efficacy of pacemakers (PMs) and implantable cardioverter defibrillators (ICDs), marked geographic and national variations in their implant rates have been documented. Tabulation of implant rates and identification of variation patterns are of only modest significance as many factors influence geographic variations. This study examined statistical data regarding implant rates and analyzed the determinants behind these variations. The results showed: (1) the implantation rate of PMs and ICDs depends heavily on national economic status and demographics. (2) Economic factors are an important determinant of implant rates, though high rates were observed in countries with modest economic resources and highly educated physicians and populations. (3) Evaluation of PM and ICD implant rates per million of an overall population, unless based on demography, can lead to significant inaccuracy when comparing different regions and countries. Adjustment of implant rates consistent with demographic parameters is required. (4) Evaluation of the implant rate as appropriate, greater or less than expected in a given country can be achieved by calculation of a "reference" implant rate, and then by its comparison with the actual implant rate. Questions remaining after this analysis are: (1) How do variations in PM and ICD implant rate relate to quality of life, morbidity, and survival? (2) Will overall patient outcomes benefit from a greater implant rate, and is a higher implant rate cost-effective? (3) Should each country attempt to reach a "reference" implant rate, independent of its approach to medicine and level of economic development? These questions can only be answered by prospective randomized trials that allow the development of recommendations based on national needs and resources.