This study found that male VA patients who screened positive on the AUDIT-C with scores of 5 or more up to a year before major surgery were at increased risk for postoperative complications compared to low risk drinkers. There was a dose-response relationship between AUDIT-C scores and postoperative complications, with complications increasing from 5.6% among low risk drinkers to 14.0% among those with the highest AUDIT-C scores, in analyses adjusted for age, smoking, and time from screening to surgery. Three types of complications known to be associated with alcohol misuse increased as AUDIT-C scores increased: surgical field, infectious, and cardiopulmonary complications. After adjustment for preoperative comorbidity and surgical complexity, patients with AUDIT-C scores of 5 or more had a 40-50% increased risk of postoperative complications.
Findings of this study are consistent with extensive prior research demonstrating a strong association between alcohol misuse and postoperative complications.3
Both heavy daily drinking (> 2-4 drinks/day) and alcohol use disorders are known to be associated with increased surgical complications.3–8, 31
This study extends prior research in several important ways. Clinicians and researchers need a practical, yet sensitive test to identify patients at risk for alcohol-related postoperative complications, and this study suggests that the AUDIT-C could meet that need. Directly asking patients if they drink over 2 or 4 drinks/day misses many patients with alcohol misuse who might benefit from preoperative alcohol abstinence.3,7,8
Therefore, studies of alcohol misuse and surgical complications have often used complex assessment protocols that are impractical for general medical settings.31,42–44
The 10-item Alcohol Use Disorders Identification Test (AUDIT) is a sensitive alcohol screen that can identify patients at increased risk for postoperative complications,45,46
but is too long for routine use in many clinical settings.47
This study showed that the AUDIT-C, which is as effective an alcohol screen as the full AUDIT 17,18,48
but brief enough for integration into routine care,23,49
could be used to identify patients at risk for alcohol-related postoperative complications. Further, the AUDIT-C identified almost twice as many patients (16.3%) compared to report of typical drinking over 2 drinks daily (8.3%). Moreover, patients who screened positive on the AUDIT-C were at increased surgical risk even though the screen was administered up to a year prior to surgery, suggesting that annual AUDIT-C screening results could be used for early preoperative identification of patients at risk for alcohol-related surgical complications.
The finding that episodic heavy drinking was not associated with increased risk of surgical complications was unexpected and has important implications. Validated single-item alcohol screening questions that ask about heavy episodic drinking are increasingly recommended for alcohol screening.24–26
This study suggests that these screens are not effective for identifying patients at risk for alcohol-related surgical complications.24
This study has several limitations. The AUDIT-C was administered on confidential mailed surveys which may yield higher scores than screening in clinical settings.50
Although the fully-adjusted model controlled for extensive covariates, residual confounding is possible. For example, if patients with alcohol misuse were more likely to have high risk surgical procedures, after adjustment for RVUs, study findings could be confounded by the type of procedure. Furthermore, the main outcome measure combined complications of varying clinical importance. In addition, 9% of patients were excluded due to non-response, potentially decreasing generalizability since surgical risks may differ for non-respondents, who tend to be younger. Similarly, the study included predominantly older men, and thus is not necessarily generalizable to women or younger men. Additional research is needed to verify AUDIT-C surgical risk groups when screening is conducted in clinical settings, and to evaluate associations between the AUDIT-C and postoperative complications in more demographically diverse samples with higher response rates, and in patients undergoing the same surgical procedure.
Despite these limitations, this study has several important strengths. The AUDIT-C was administered in a standard fashion and was available for a large, national sample of men who completed alcohol screening in the year prior to surgery. Additionally, assessment of outcomes was standardized and abstractors were blinded to AUDIT-C results and unaware of this study.
This study has several implications for general medicine practice. Health care systems are increasingly implementing alcohol screening so that patients with alcohol misuse can be offered brief alcohol interventions.23, 49, 51
Routine AUDIT-C screening could also be used for early identification of patients at risk for alcohol-related surgical complications. Health systems using the AUDIT-C could incorporate review of alcohol screening results into surgical referrals or nursing assessments when surgery is scheduled. Patients with scores ≥ 5 whose drinking has not changed at the time of referral to surgery could be counseled that their drinking puts them at increased risk for serious complications and encouraged to abstain preoperatively. Available evidence from a single trial suggests that abstaining for a month preoperatively significantly reduces postoperative complications.2
The high participation rate in that trial2
suggested that many patients are willing to abstain temporarily in an attempt to decrease surgical risks.
To summarize, the AUDIT-C provides a sensitive and practical way to identify preoperative patients at risk for alcohol-related surgical complications. Alcohol screening with the AUDIT-C up to a year prior to surgery, as in routine annual alcohol screening, identified over 16% of men undergoing major surgery who were at increased risk for alcohol-related surgical morbidity. Preoperative strategies to reduce alcohol-related surgical complications should now be further tested in this high-risk group. In the meantime, patients with AUDIT-C scores ≥ 5 should be encouraged to abstain for the month preoperatively, and those requiring urgent or emergent surgeries should be managed expectantly with regard to postoperative complications.