Geographic variation in the use of post-acute care

Objective. To assess the extent and consistency of geographic differences in the use of post-acute care (PAC), and the stability of this pattern of variation. Data Sources. The 5 percent Medicare data sample for 1996, 1997, and the first eight months of 1998 were used. Study Design. Patterns of PAC use for various Diagnosis-related Groups (DRGs) across states (33 with enough cases per year) and census divisions were examined. The consistency of relative rankings for overall PAC use and use within defined DRGs was compared. Principal Findings. PAC use varied substantially across regions. For example, the extent of any PAC use for stroke patients varied by 12 percentage points among census regions in 1998. The pattern of PAC use was quite consistent across years; 30 of the 36 possible Spearman rank order correlations were statistically significant with coefficients ranging from 0.35 to 0.95 among the DRGs studied. The correlations among DRGs were generally high. For skilled nursing facility use, all the correlations were above 0.5 and were statistically significant; in general the patterns were highest within medical DRGs (0.65-0.93). Conclusions. The variation in PAC use is not a statistical artifact. It is likely the result of several forces: practice styles, supply of services, and local regulatory practices.