Variation over time in preventable hospitalization rates across counties.

Background: The Agency for Health Care Research and Quality developed 14 prevention quality indicators (PQIs), including four PQIs related to preventable hospitalizations for diabetes and one to asthma. Quality indicators vary across counties, but variation over time has not been described.

Methods: The Kentucky Cabinet for Health and Family Services published PQI data for each county in Kentucky in each of the 3 years from 2006 to 2008. Variation and correlations among PQI measures were calculated.

Results: PQI rates often varied 10-fold between counties. Repeated measures of four PQIs were highly correlated, suggesting local health care processes that are stable over time. Some PQIs, such as PQI01--emergent complications of blood glucose control--correlated poorly with other measures. Other PQIs are correlated over geography and time, including PQI03 (long-term complications of diabetes); PQI14 (poorly controlled diabetes); and PQI15 (asthma).

Conclusions: These county PQI measures were stable over time. Stability implies that PQI measures were not the result of random processes and did not rapidly shift. However, some health improvement needs varied between counties. Although tailoring health promotion interventions to each county's needs may be complex, stable needs afford time to undertake targeted quality improvement efforts.