Patient healthcare spending after the No Surprises Act: quasi-experimental difference-in-differences study

To estimate changes in healthcare spending in the US after implementation of the No Surprises Act (NSA) in 2022 among adults with direct purchase private insurance.

Quasi-experimental difference-in-differences study.

24 US states.

Adults aged 19-64 years with direct purchase private insurance who participated in the Annual Social and Economic Supplement of the Current Population Survey 2019-24 and resided in states that gained NSA surprise billing protections (intervention states) or in states with comprehensive protections already in place (control states).

Inflation adjusted out-of-pocket spending, insurance premium spending, and high burden medical spending (defined as spending >10% of total family income on both out-of-pocket and premium costs).

The study population included 17 351 privately insured adults, with 8204 residing in the 18 intervention states and 9147 in the six control states. After implementation of the NSA, out-of-pocket spending showed a decline among privately insured adults in intervention states (from $3674 (£2776; €3214) to $2922, relative percentage change -16.5%, 95% confidence interval (CI) -27.9% to -3.2%), but not among privately insured adults in control states ($2704 to $2550, 1.9%, -11.6% to 17.4%). A significant differential reduction was observed in out-of-pocket spending among privately insured adults in intervention states compared with control states after the NSA (relative percentage change -18.0%, -30.2% to -3.7%; absolute change -$567, 95% CI -$1031 to -$102; P=0.02). In contrast, no differential changes were observed in premium spending (relative percentage change 1.9%, -13.9% to 20.7%; absolute change $93, -$737 to $924; P=0.82) and in high burden medical spending (absolute percentage point change -1.0%, 95% CI -5.2% to 3.1%, P=0.62) between the two groups. These findings were consistent across sociodemographic characteristics, including sex, race/ethnicity, poverty status, education level, and employment status.

Substantial declines occurred in out-of-pocket spending among direct purchase privately insured adults who gained NSA surprise billing protections. In contrast, premium spending and high burden medical spending did not change. Additional policy efforts are needed to reduce healthcare related financial strain in the US.