Does health insurance status influence surgical complications? An analysis of abdominal, thoracic and vascular interventions in a Swiss tertiary referral centre.

STUDY AIMS: In Switzerland, basic health insurance is compulsory. Supplementary or private health insurance may be arranged, providing advantages such as hospital comfort and a free choice of doctors. Since there is limited data on whether insurance status influences the outcome of surgery, this study aimed to investigate the influence of supplementary insurance status on the overall complication occurrence in a group of abdominal, thoracic and vascular surgeries.

METHODS: This study is based on surgical patient data prospectively collected between September 2016 and March 2018 from one participating Swiss tertiary referral hospital of the StOP?-trial (NCT02428179), which investigated the effect of structured intraoperative briefings on patient outcomes. First, additional data, including insurance status, demographic and surgical parameters within 30 days was collected. Second, due to endogeneity concerns in the sample driven by selective access to a supplementary insurance, propensity-score matching (PSM) was used to balance samples for the treatment variable (insurance status) by demographic parameters and surgical complexity. The primary outcome was the estimated treatment effect of a supplementary insurance on the occurrence of surgical complications, categorised by the Clavien-Dindo classification (CDC). Finally, multiple logistic regression was used to detect further conditional associations of demographic and surgical variables with the occurrence of complications.

RESULTS: Of all 3173 procedures, 64.3% were elective, 48.2% had a higher surgical complexity (excluding appendectomies, cholecystectomies, hernia surgery and lymph node excision) and 18.6% of all patients had supplementary insurance. The occurrence of complications, including surgical site infection and postoperative complications, was 30.4%. After matching 591 patients with basic insurance to 591 patients with a supplementary insurance, no significant association between insurance status and complications could be found (crude odds ratio [OR] [95% CI]: 0.97 [0.77-1.23]). In contrast to insurance status, multiple logistic regression identified that variables such as surgical complexity (adjusted OR [95% CI]: 1.80 [1.27-2.56]), contamination (adjusted OR [95% CI]: 1.90 [1.41-2.56]) and duration of surgery (adjusted OR [95% CI]: 1.008 [1.006-1.009]) were associated with the occurrence of complications.

CONCLUSION: Despite the different cost-liable insurance levels, there were no significant differences and, therefore, no disadvantages for basic insured patients regarding the complication rate in this Swiss cohort undergoing abdominal, thoracic or vascular surgery.