Interaction Effects of Acute Kidney Injury, Acute Respiratory Failure, and Sepsis on 30-Day Postoperative Mortality in Patients Undergoing High-Risk Intraabdominal General Surgical Procedures.
BACKGROUND
Acute kidney injury (AKI), acute respiratory failure, and sepsis are distinct but related pathophysiologic processes. We hypothesized that these 3 processes may interact to synergistically increase the risk of short-term perioperative mortality in patients undergoing high-risk intraabdominal general surgery procedures.


METHODS
We performed a retrospective, observational cohort study of data (2005-2011) from the American College of Surgeons-National Surgical Quality Improvement Program, a high-quality surgical outcomes data set. High-risk procedures were those with a risk of AKI, acute respiratory failure, or sepsis greater than the average risk in all intraabdominal general surgery procedures. The effects of AKI, acute respiratory failure, and sepsis on 30-day mortality were assessed using a Cox proportional hazards model. Additive interactions were assessed with the relative excess risk due to interaction.


RESULTS
Of 217,994 patients, AKI, acute respiratory failure, and sepsis developed in 1.3%, 3.7%, and 6.8%, respectively. The 30-day mortality risk with sepsis, acute respiratory failure, and AKI were 11.4%, 24.1%, and 25.1%, respectively, compared with 0.85% without these complications. The adjusted hazard ratios and 95% confidence intervals for a single complication (versus no complication) on mortality were 7.24 (6.46-8.11), 10.8 (8.56-13.6), and 14.2 (12.8-15.7) for sepsis, AKI, and acute respiratory failure, respectively. For 2 complications, the adjusted hazard ratios were 30.8 (28.0-33.9), 42.6 (34.3-52.9), and 65.2 (53.9-78.8) for acute respiratory failure/sepsis, AKI/sepsis, and acute respiratory failure/AKI, respectively. Finally, the adjusted hazard ratio for all 3 complications was 105 (92.8-118). Positive additive interactions, indicating synergism, were found for each combination of 2 complications. The relative excess risk due to interaction for all 3 complications was not statistically significant.


CONCLUSIONS
In high-risk general surgery patients, the development of AKI, acute respiratory failure, or sepsis is independently associated with an increase in 30-day mortality. In addition, the development of 2 complications shows significant positive additive interactions to further increase the risk of mortality. Our findings suggest that interactions between these 3 perioperative complications increase the risk of mortality more than would be expected by the independent effects of each complication alone.
From the *Department of Anesthesiology, Columbia University Medical Center, New York, New York; and †Department of Epidemiology, Columbia Mailman School of Public Health, New York, New York.
Minjae
M
Kim
Joanne E
JE
Brady
Guohua
G
Li
D000208:Acute Disease; D058186:Acute Kidney Injury / Q000401:mortality* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality / Q000639:trends; D011183:Postoperative Complications / Q000209:etiology / Q000401:mortality*; D012131:Respiratory Insufficiency / Q000401:mortality* / Q000601:surgery; D012189:Retrospective Studies; D012307:Risk Factors; D018805:Sepsis / Q000401:mortality* / Q000601:surgery; D013514:Surgical Procedures, Operative / Q000009:adverse effects*