ASCs are more likely to open in counties with stronger healthcare infrastructure and higher socioeconomic advantage, according to a study published in Health Affairs Scholar in October.
The cross-sectional study used 2019 county data and a standard measure of local disadvantage. Researchers then looked at which types of counties were more likely to get a new ASC between 2014 and 2021.
Here are nine trends and stats to know:
1. ASC growth clusters where ASCs already exist. The strongest predictor of a new opening was the presence of an existing ASC in the county. Adjusted opening rates were 44.7% in counties with an ASC compared to 13.8% in counties without one.
2. The total number of ASCs increased over the decade. ASCs in the sample rose from 5,012 in 2011 to 5,293 in 2021, a statistically significant increase.
3. Affluent counties are far more likely to gain ASCs. Counties in the least-deprived (best-off) ADI quartile had an adjusted opening rate of 31.9%, compared to 19.9% in the most-deprived quartile. Odds of opening fell steadily as deprivation increased.
4. Counties with larger Black Medicare populations saw somewhat higher opening rates. Counties in the highest quartile of Black beneficiaries had adjusted opening rates of 28.7% versus 22% in the lowest quartile.
5. Physician-rich counties attract more ASCs. Counties in the highest per-capita physician quartile saw openings 31.4% of the time, compared to 21.8% in the lowest quartile, indicating ASCs tend to follow clinician density and established outpatient ecosystems.
6. Hospital capacity is also linked to ASC entry. Counties in the highest hospital-bed quartile had an adjusted opening rate of 32.6%, compared to 20.4% in the lowest-bed quartile. New ASCs are more likely to open where broader healthcare infrastructure is already robust.
7. Rurality wasn’t a significant factor after adjustment. Adjusted opening rates were 25.4% in urban counties versus 23.8% in rural counties, and the rural odds ratio (0.69) was not statistically significant. In this model, resource and advantage mattered more than a simple rural-urban split.
8. Operating room supply didn’t meaningfully predict openings. Differences by county OR quartile were not statistically significant, suggesting ASC market entry is less about raw OR capacity and more about financial positioning within resource-dense markets.
9. The study authors tie inequities to incentives and regulation. The study argues that strong profitability incentives for low-risk outpatient surgery, combined with a relatively light regulatory environment for ASC entry (including many states without certificate-of-need requirements and CMS expanding ASC-eligible procedures), likely contributes to the uneven growth pattern.
