Does increased use of private health care reduce the demand for NHS care? A prospective survey of general practice referrals

Background The use of the private sector for health care is increasing, but it is unclear whether this will reduce demand on the NHS. The aim of this study was to examine the relationship between private and NHS outpatient referral rates accounting for their association with deprivation. Methods This is a prospective survey of general practitioner referrals to private and NHS consultant-led services between 1 January and 31 December 2001 from 10 general practices in the Trent Focus Collaborative Research Network, United Kingdom. Patient referrals were aggregated to give private and NHS referral rates for each electoral ward in each practice. Results Of 17 137 referrals, 90.4 per cent (15 495) were to the NHS and 9.6 per cent (1642) to the private sector. Private referral rates were lower in patients from the most deprived fifth of wards compared with the least deprived fifth (rate ratio 0.25, 95 per cent CI 0.15 to 0.41, p < 0.001), whereas NHS referral rates were slightly higher in patients in the most deprived fifth of wards (rate ratio 1.18, 95 per cent CI 0.98 to 1.42, p = 0.08) both after age standardisation and adjustment for practice. The NHS referral rate was significantly higher (rate ratio 1.40, 95 per cent CI 1.15 to 1.71, p = 0.001) in wards with private referral rates in the top fifth compared with the bottom fifth after adjustment for deprivation and practice. Conclusions Increased private health care activity does not reduce the demand for NHS care: NHS and private referral rates were positively associated with each other after adjusting for age, deprivation and practice.