Limitations
There are several limitations inherent to this observational study using
administrative data. First, Medicare administrative claims data are a
secondary database used primarily for billing purposes, not for clinical
research purposes; therefore, traditional clinical adjudication is not
conducted. It is possible that reinterventions, complications, or
comorbidities could be missed, improperly coded, or inadequately
documented in administrative claims. However, our prior analyses suggest
that this probability is low,6 and, if anything,
claims-based studies tend to overestimate adverse
events.14 We would also not expect this to have a
differential impact between the two study arms. Second, as with any
observational study, the possibility of residual confounding following
statistical adjustment for measured confounders cannot be completely
eliminated. Third, because our study does not include device
interrogation data, we are unable to assess variables such as programmed
lower rates, pacing thresholds, and battery longevity which may be of
particular interest when assessing the need for device reintervention.
Finally, due to data availability, this analysis is limited to the
Medicare FFS population and does not capture outcomes beyond December
31, 2020.