J Am Coll Radiol. 2020 Aug 19:S1546-1440(20)30788-2. doi: 10.1016/j.jacr.2020.04.035. Online ahead of print.
PURPOSE: The aim of this study was to explore state-level relationships between the incidence and payout amounts for medical malpractice claims and Medicare imaging utilization and spending across the United States.
METHODS: Using claims data from a 5% sample of Medicare beneficiaries for 2004 to 2016, annual state population-adjusted rates of imaging utilization and spending were calculated. Using National Practitioner Data Bank files, all paid physician malpractice claims were identified, and lagged state population-adjusted rolling averages of paid claim frequencies and payout amounts were calculated. Controlling for secular trends and state fixed effects with robust standard errors clustered at the state level to account for serial autocorrelation, associations between imaging utilization and lagged paid malpractice claims were assessed using multivariate regression models. Log-log model specification was used to obtain elasticity measures.
RESULTS: Between 2004 and 2016, national Medicare diagnostic imaging utilization and spending declined by 31.4% and 47.2%, respectively (from 355,057 to 243,517 examinations and from $28,591,146 to $15,099,291 per 100,000 beneficiaries). Overall national paid malpractice claims and payout amounts declined by 46.4% and 39.6%, respectively (from 4.83 to 2.59 claims and from $1,803,565 to $1,089,112 per 100,000 population). After controlling for secular trends and state fixed effects, advanced imaging utilization was positively associated with the lagged number of per capita paid malpractice claims. Each 1% increase in average paid malpractice claims was associated with a subsequent 0.20% increase in advanced imaging utilization (P = .001).
CONCLUSIONS: Positive associations between paid malpractice claims and advanced Medicare imaging utilization support the contention that US physicians use medical imaging as a defensive medicine strategy.