R is a popular environment for clinical data analysis. It does not directly support big data workloads.
Both, the Message Passing Interface (MPI) and SparkR allow to parallelize computational demanding workloads on clusters.
SparkR offers elastic resources even on non-dedicated hardware and tight integration with Hadoop distributed services.
SparkR requires minimal changes to original code in R in order to utilize parallel execution.
Computation in SparkR scales better than with the Message Passing Interface (MPI) due to optimized data communication.