Variation in preoperative stress testing by patient, physician and surgical type: a cohort study

OBJECTIVES: To describe variation in and drivers of contemporary preoperative cardiac stress testing. SETTING: A dedicated preoperative risk assessment and optimisation clinic at a large integrated medical centre from 2008 through 2018. PARTICIPANTS: A cohort of 118 552 adult patients seen by 104 physicians across 159 795 visits to a preoperative risk assessment and optimisation clinic. MAIN OUTCOME: Referral for stress testing before major surgery, including nuclear, echocardiographic or electrocardiographic-only stress testing, within 30 days after a clinic visit. RESULTS: A total of 8303 visits (5.2%) resulted in referral for preoperative stress testing. Key patient factors associated with preoperative stress testing included predicted surgical risk, patient functional status, a previous diagnosis of ischaemic heart disease, tobacco use and body mass index. Patients living in either the most-deprived or least-deprived census block groups were more likely to be tested. Patients were tested more frequently before aortic, peripheral vascular or urologic interventions than before other surgical subcategories. Even after fully adjusting for patient and surgical factors, provider effects remained important: marginal testing rates differed by a factor-of-three in relative terms and around 2.5% in absolute terms between the 5th and 95th percentile physicians. Stress testing frequency decreased over the time period; controlling for patient and physician predictors, a visit in 2008 would have resulted in stress testing approximately 3.5% of the time, while a visit in 2018 would have resulted in stress testing approximately 1.3% of the time. CONCLUSIONS: In this large cohort of patients seen for preoperative risk assessment at a single health system, decisions to refer patients for preoperative stress testing are influenced by various factors other than estimated perioperative risk and functional status, the key considerations in current guidelines. The frequency of preoperative stress testing has decreased over time, but remains highly provider-dependent.