The National Veterans Administration Surgical Risk Study: risk adjustment for the comparative assessment of the...

The use of surgical outcome in the comparative assessment of the quality of surgical care is predicted on the development of proper models that adjust for the severity of the preoperative risk factors of the patient. The National Veterans Administration Surgical Risk Study was designed to collect reliable, valid data about patient risk and outcome for major surgery in the Veterans Health Administration (VHA) and to report comparative risk-adjusted surgical morbidity and mortality rates for surgical services in VHA. This study describes the rationale and methods used in the Risk Study and reports on the frequency distribution of the data elements that will be used in the development of risk-adjusted reporting of surgical outcome.

This study was a prospective observational study in which dedicated nurses collected preoperative, intraoperative, and outcome data on patients undergoing noncardiac operations using general, spinal, and epidural anesthesia in 44 Veterans Administration Medical Centers. Outcome measures included all cause mortality within the 30 days after the index procedure and 21 major morbidities.

Eighty-three thousand nine hundred fifty-eight cases meeting inclusion criteria were entered in the study between October 1, 1991 and December 31, 1993. Ninety-seven percent of patients were men, with a mean age of 60.1 +/- 13.6 (standard deviation) years. The most common preoperative risk factors were smoking (40.7 percent) and hypertension (36.1 percent). Of the patients, 84.6 percent had one or more risk factors. The most common procedures were transurethral resection of the prostate gland (6.7 percent), total knee replacement (3.1 percent), thromboendarterectomy (2.4 percent), partial colectomy (2.2 percent), and total hip replacement (2 percent). The unadjusted mortality rate was 3.1 percent at 30 days. The most common postoperative morbidities were pneumonia (3.6 percent), urinary tract infection (3.5 percent), and failure to wean from the ventilator at 48 hours postoperatively (3.2 percent). Seventeen percent of the patients have one or more major complications.

The Veterans Health Administration has successfully implemented an outcome reporting system for major surgery that prospectively collects patient risk and outcome information reliably and validly. Risk adjustment models and comparative hospital-specific rates of risk-adjusted outcomes are currently being developed.