Association of Preoperative Medical Consultation With Reduction in Adverse Postoperative Outcomes and Use of Processes of Care Among Residents of Ontario, Canada

Abstract

ImportanceIt is uncertain whether preoperative medical consultation reduces adverse postoperative clinical outcomes.ObjectiveTo investigate the association of preoperative medical consultation with reduction in adverse postoperative outcomes and use of processes of care.Design, Setting, and ParticipantsThis was a retrospective cohort study using linked administrative databases from an independent research institute housing routinely collected health data for Ontario’s 14 million residents, including sociodemographic features, physician characteristics and services, and receipt of inpatient and outpatient care. The study sample included Ontario residents aged 40 years or older who underwent their first qualifying intermediate- to high-risk noncardiac operation. Propensity score matching was used to adjust for differences between patients who did and did not undergo preoperative medical consultation with discharge dates between April 1, 2005, and March 31, 2018. The data were analyzed from December 20, 2021, to May 15, 2022.ExposuresReceipt of preoperative medical consultation in the 4 months preceding the index surgery.Main Outcomes and MeasuresThe primary outcome was 30-day all-cause postoperative mortality. Secondary outcomes included 1-year mortality, inpatient myocardial infarction and stroke, in-hospital mechanical ventilation, length of stay, and 30-day health system costs.ResultsOf the total 530 473 individuals (mean [SD] age, 67.1 [10.6] years; 278 903 [52.6%] female) included in the study, 186 299 (35.1%) received preoperative medical consultation. Propensity score matching resulted in 179 809 well-matched pairs (67.8% of the full cohort). The 30-day mortality rate was 0.9% (n = 1534) in the consultation group and 0.7% (n = 1299) in the control group (odds ratio [OR], 1.19; 95% CI, 1.11-1.29). The ORs for 1 year mortality (OR, 1.15; 95% CI, 1.11-1.19), inpatient stroke (OR, 1.21; 95% CI, 1.06-1.37), in-hospital mechanical ventilation (OR, 1.38; 95% CI, 1.31-1.45), and 30-day emergency department visits (OR, 1.07; 95% CI, 1.05-1.09) were higher in the consultation group; however, the rates of inpatient myocardial infarction did not differ. The lengths of stay in acute care were a mean (SD) 6.0 (9.3) days in the consultation group and 5.6 (10.0) days in the control group (difference, 0.4 [95% CI, 0.3-0.5] days), and the median (IQR) total 30-day health system cost was CAD $317 ($229-$959) (US $235 [$170-$711]) higher in the consultation group. Preoperative medical consultation was associated with increased use of preoperative echocardiography (OR, 2.64; 95% CI, 2.59-2.69) and cardiac stress tests (OR, 2.50; 95% CI, 2.43-2.56) and higher odds of receiving a new prescription for β-blockers (OR, 2.96; 95% CI, 2.82-3.12).Conclusions and RelevanceIn this cohort study, preoperative medical consultation was not associated with a reduction but rather with an increase in adverse postoperative outcomes, suggesting a need for further refinement of target populations, processes, and interventions related to preoperative medical consultation. These findings highlight the need for further research and suggest that referral for preoperative medical consultation and subsequent testing should be carefully guided by individual-level consideration of risks and benefits.

Preoperative Medical Consultation—Questioning a Long-Standing Practice

“…To the Editor We congratulate Dr Beckerleg and colleagues on their exploration of this topic and their findings that raise questions regarding the relevance of perioperative medical consultation and its association with patient outcomes. The goal of perioperative consultation has been to reduce surgical morbidity and adverse events; however, its effects have been challenging to study in an organized manner.…”

“…Although this article highlights the importance of studying the role and benefit of preoperative medical optimization, the conclusion that “preoperative medical consultation was not associated with a reduction but rather with an increase in adverse postoperative outcomes” is perhaps too definitive. A causal link is difficult to identify within the constraints of this study.…”

“…The authors conclude that ongoing support for preoperative medical consultation should hinge on the production of credible evidence of benefit . Although the general practice of perioperative consultation has not demonstrated benefit in randomized clinical trials, specific perioperative interventions have shown improvement in perioperative patient outcomes.…”

Preoperative Medical Consultation—Questioning a Long-Standing Practice

“…To the Editor Dr Beckerleg and colleagues observed that preoperative medical consultations were not associated with a reduction but rather with an increase in adverse postoperative outcomes . Unfortunately, from the article we learn little regarding the indications, quality, or results of these preoperative medical consultations.…”

Preoperative Medical Consultation—Questioning a Long-Standing Practice—In Reply

“…Regarding comments about patient selection and confounding, we agree and acknowledged in our study limitations that our conclusions do not apply to patients who may have had their surgical procedures canceled after preoperative medical consultations, and that the issue of potential residual confounding is inherent in observational designs. Whether through propensity score methods or regression-based adjustment, residual confounding is likely to remain.…”