Outpatient internal medicine preoperative evaluation: a randomized clinical trial

The purpose of this study was to evaluate the effect on resource use of a program outpatient internal medicine preoperative evaluation in a two arm parallel design randomized clinical trial. In a tertiary care teaching Veterans Affairs hospital, 355 patients (179 inpatient arm, 176 outpatient arm)(mean age 65.5 years) were referred for internal medicine preoperative evaluation before elective surgery. Outpatient internist preoperative evaluation was performed 2 to 3 weeks before admission for surgery in the experimental arm with preoperative laboratory and radiology testing performed during the visit. The control arm was admitted for surgery without outpatient evaluation. The main outcome measure was the length of stay. Preoperative length of stay was significantly reduced from 2.9 days in the inpatient arm to 1.6 days in the outpatient arm (P < 0.001, 95% confidence interval of the difference, -0.8 to -1.8 days). Postoperative length of stay in the outpatient arm (3.6 days) was slightly but not significantly longer than the inpatient arm (3.0 days) (95% confidence interval of the increase, -0.6 to 1.8 days). Total length of stay showed no significant difference between the outpatient (5.5 days) and inpatient (6.0 days) arms (95% confidence interval of the difference, -2.0 to 1.1 days). Unnecessary admissions, defined as patients admitted who were admitted but did not undergo surgery, were decreased significantly comparing the inpatient arm (12.3%) to the outpatient arm (5.7%) (95% confidence interval of the difference, 0.5% to 12.7%). Measures of resource use showed no difference between arms including laboratory tests (95% C.I. of the difference, -3.0 to 6.8 tests), imaging tests (95% C.I. of the difference, -0.5 to 0.8 tests) were administered. A significant increase in the use of consultants between the outpatient arm (1.3 consultations) and inpatient arm (0.9 consultations) was discovered (95% C.I. of the difference, 0.2 to 0.6). Patients health status after discharge and satisfaction with care were not different between the two arms of the investigation. A program of outpatient internal medicine preoperative evaluation significantly reduced preoperative length of stay with a lesser effect on total length of stay. Unnecessary admission of patients for elective surgery were reduced by this program.