Effects of provider incentives on dental X-raying in NHS Scotland: what happens if patients switch providers?

BACKGROUND: In many market settings individuals are encouraged to switch health care providers as a means of ensuring more competition. Switching may have a potentially undesirable side effect of increasing unnecessary treatment. Focusing on the most common source of medical radiation (dental X-rays), the purpose of this study was to assess whether, upon switching dentist, X-ray exposure increases depending on the type of provider payment. METHODS: The analysis used longitudinal data from 2005 to 2016 covering a 5% random sample of the Scottish adult population covered by the National Health Service (NHS). Multiple fixed-effects panel regression analyses were employed to determine the correlation of provider remuneration with patients’ likelihood of receiving an X-ray upon switching to a new dentist other things equal. A broad set of covariates including a patient’s copayment status was controlled for. RESULTS: Upon switching to a dentist who was paid fee-for-service, patients had a by 9.6%-points (95% CI 7.4–11.8%) higher probability of receiving an X-ray, compared to switching to a salaried dentist. Results were robust when accounting for patient exemption status, as well as unobserved patient and dentist characteristics. CONCLUSIONS: In comparison to staying with the same dentist, patients may be exposed to substantially more X-rays upon switching to a dentist who is paid fee-for-service. There may need to be better guidance and regulation to protect the health of those who have to switch provider due to moving and greater caution in advocating voluntary switching. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10198-021-01348-3.