Predictors, Risk Factors and Outcome Following Major Surgery (PROFS)

This is a multicenter, prospective, observational study. Length of patient recruitment is 12 weeks, the length of observation is 360 postoperative days. The expected number of patients is 1000.

Patients will be selected from the operation planning software on each study site. It is done by daily screening of the operation list and will be enrolled by applying the inclusion criteria. The criteria of surgical severity will be assessed by the UK surgical severity grading system ( AXA PPP/ Specialist Procedure Codes, United Kingdom). For that purpose a scroll list will be used, which is available on the website of the Surgical Outcome Risk Tool calculator.

Patient characteristics will be prospectively collected from medical records: age, gender, co-morbidities, medical history, physical activity, blood pressure, heart rate, oxygen saturation and neurological function; routine laboratory findings; type, complexity, urgency of surgery, incision localization and malignancy; lowest intraoperative systolic blood pressure, heart rate. The outcomes are the postoperative morbidity (assessed by the Postoperative Morbidity Survey) classified by the Clavien-Dindo classification tool (during hospital stay), and mortality, use of medications, hospital re-admissions (0-360 days) and new occurrence in different disease related national quality registries.Relationships between postoperative morbidity (POMS) the severity of morbidity (Clavien Dindo) and mortality will be analyzed. For illustration, Kaplan Meyer plots will be used, and for analyses Cox proportional hazard model will be used with adjustment for sex and age.

Additional changes:

1. The length of observation for survival was extended to 3 years. The mortality at 3 years will be analyzed addressing the relationship between the postoperative morbidity (POMS) and mortality. Cox regression model will be used with adjustment of age, comorbidity and malignancy.
2. Validation of Surgical Outcome Risk Tool is planned in two populations related to the PROFS study: eligible and background population. As the PROFS cohort was manually selected, we presumed that the eligible population is larger than the enrolled population.To enable electronic selection of the eligible population, we have developed a script, which translates the Swedish surgical codes into the UK severity codes. Using the same script we will classify the surgical severity in the background population of the PROFS cohort. Variables included in the Surgical Outcome Risk Tool will be extracted from the operation databases of each study site. The date of death will be extracted from the Swedish National Adress Registry and the malignancy from the registry of National Swedish Cancer Registry.