[Analysis of mortality and relative prognostic factors in general surgery: use of the multiple logistic regression model].

Surgical risk is defined as the occurrence of complications arising in the individual as a result of surgical stress. The ability to forecast these consequences is an important factor in determining decision taken by surgeon. Several attempts have been made to quantify postsurgical prospects but up till now no overall solution has been found. This paper attempts to define a multifactorial risk index for adults subjected to surgery, with respect to immediate and early per- and post-surgical complications. 1182 adult patients, 14 yrs or more, surgically treated not for urgency during 1985 in six Italian centres, were prospectively studied in order to derive a multivariate prognostic index of after surgery mortality. Stepwise logistic regression model was applied to a set of preoperative and operative factors, five of which were found significantly correlate with death: nutritional status, renal failure, reintervention, bacterial contamination during surgery, age greater than 70 years. Thus, from regression coefficients, scores were derived for modalities of significant variables, allowing to build four classes of risk patients: low (less than 1%), medium (between 1% and 10%), high (between 10% and 50%), extremely high risk (greater than 50%).