Disparity in clinical outcomes after cardiac surgery between private and public (NHS) payers in England

Background: There is little known about how payer status impacts clinical outcomes in a universal single-payer system such as the UK National Health Service (NHS). The aim of this study was to evaluate the relationship between payer status (private or public) and clinical outcomes following cardiac surgery from NHS providers in England.

Methods: The National Adult Cardiac Surgery Audit (NACSA) registry was interrogated for patients who underwent adult cardiac surgery in England from 2009 to 2018. Information on socioeconomic status were provided by linkage with the Iteration of the English Indices of Deprivation (IoD). The primary outcome was in-hospital mortality. Secondary outcomes included incidence of in-hospital postoperative cerebrovascular accident (CVA), renal dialysis, sternal wound infection, and re-exploration. To assess whether payer status was an independent predictor of in-hospital mortality, binomial generalized linear mixed models (GLMM) were fitted along with 17 items forming the EuroSCORE and the IoD domains.

Findings: The final sample consisted of 280,209 patients who underwent surgery in 31 NHS hospitals in England from 2009 to 2018. Of them, 5,967 (2‧1%) and 274,242 (97‧9%) were private and NHS payers respectively. Private payer status was associated with a lower risk of in-hospital mortality (OR 0‧79; 95%CI 0‧65 – 0‧97;P=0‧026), CVA (OR 0‧77; 95%CI 0‧60 – 0‧99; P=0‧039), need for re-exploration (OR 0‧84; 95%CI 0‧72 – 0‧97; P=0‧017) and with non-significant lower risk of dialysis (OR 0‧84; 95%CI 0‧69 – 1‧02; P=0‧074). Private payer status was found to be independently associated with lower risk of in-hospital mortality in the elective subgroup (OR 0‧76; 95%CI 0‧61 – 0‧96; P=0‧020) but not in the non-elective subgroup (OR 1‧01; 95%CI 0‧64 – 1‧58; P=0‧976).

Interpretation: In conclusion, using a national database, we have found evidence of significant beneficial effect of payer status on hospital outcomes following cardiac surgery in favour of private payers regardless their socioeconomic factors.