UC Berkeley

Background

The State Innovation Models (SIM) Initiative invested $254 million in 6 states in Round 1 to accelerate delivery system and payment reforms.

Objective

The objective of this study was to examine the association of early SIM implementation and diagnosed diabetes prevalence among adults and hospitalization rates among diagnosed adults.

Research design

Quasi-experimental design compares diagnosed diabetes prevalence and hospitalization rates before SIM (2010-2013) and during early implementation (2014) in 6 SIM states versus 6 comparison states. County-level, difference-in-differences regression models were estimated.

Subjects

The annual average of 4.5 million adults aged 20+ diagnosed with diabetes with 1.4 million hospitalizations in 583 counties across 12 states.

Measures

Diagnosed diabetes prevalence among adults and hospitalization rates per 1000 diagnosed adults.

Results

Compared with the pre-SIM period, diagnosed diabetes prevalence increased in SIM counties by 0.65 percentage points (from 10.22% to 10.87%) versus only 0.10 percentage points (from 9.64% to 9.74%) in comparison counties, a difference-in-differences of 0.55 percentage points. The difference-in-differences regression estimates ranged from 0.49 to 0.53 percentage points (P<0.01). Regression results for ambulatory care-sensitive condition and all-cause hospitalization rates were inconsistent across models with difference-in-differences estimates ranging from -5.34 to -0.37 and from -13.16 to 0.92, respectively.

Conclusions

SIM Round 1 was associated with higher diagnosed diabetes prevalence among adults after a year of implementation, likely because of SIM's emphasis on detection and care management. SIM was not associated with lower hospitalization rates among adults diagnosed with diabetes, but the SIM's long-term impact on hospitalizations should be assessed.