Association between blood alcohol concentration and mortality in critical illness.

OBJECTIVE

In animal models of renal, intestinal, liver, cardiac, and cerebral ischemia, alcohol exposure is shown to reduce ischemia-reperfusion injury. Inpatient mortality of trauma patients is shown to be decreased in a dose-dependent fashion relative to blood alcohol concentration (BAC) at hospital admission. In this study, we examined the association between BAC at hospital admission and risk of 30-day mortality in critically ill patients.

DESIGN

We performed a 2-center observational study of patients treated in medical and surgical intensive care units in Boston, Massachusetts.

SETTING

Medical and surgical intensive care units in 2 teaching hospitals in Boston, Massachusetts.

PATIENTS

We studied 11850 patients, 18 years or older, who received critical care between 1997 and 2007. The exposure of interest was the BAC determined in the first 24 hours of hospital admission and categorized a priori as BAC less than 10 mg/dL (below level of detection), 10 to 80 mg/dL, 80 to 160 mg/dL, and greater than 160 mg/dL. The primary outcome was all-cause mortality in the 30 days after critical care initiation. Secondary outcomes included 90- and 365-day mortality after critical care initiation. Mortality was determined using the US Social Security Administration Death Master File, and 365-day follow-up was present in all cohort patients. Adjusted odds ratios (ORs) were estimated by multivariable logistic regression models with inclusion of covariate terms thought to plausibly interact with both BAC and mortality. Adjustment included age, sex, race (white or nonwhite), type (surgical vs medical), Deyo-Charlson index, sepsis, acute organ failure, trauma, and chronic liver disease.

RESULTS

Thirty-day mortality of the cohort was 13.7%. Compared to patients with BAC levels less than 10 mg/dL, patients with levels greater than or equal to 10 mg/dL had lower odds of 30-day mortality; for BAC levels 10 to 79.9 mg/dL, the OR was 0.53 (95% confidence interval [CI], 0.40-0.70); for BAC levels 80 to 159.9 mg/dL, it was 0.36 (95% CI, 0.26-0.49); and for BAC levels greater than or equal to 160 mg/dL, it was 0.35 (95% CI, 0.27-0.44). After multivariable adjustment, the OR of 30-day mortality was 0.97 (0.72-1.31), 0.79 (0.57-1.10), and 0.69 (0.54-0.90), respectively. When the cohort was analyzed with sepsis as the outcome of interest, the multivariable adjusted odds of sepsis in patients with BAC 80 to 160 mg/dL or greater than 160 mg/dL were 0.72 (0.50-1.04) or 0.68 (0.51-0.90), respectively, compared to those with BAC less than 10 mg/dL. In a subset of patients with blood cultures drawn (n=4065), the multivariable adjusted odds of bloodstream infection in patients with BAC 80 to 160 mg/dL or greater than 160 mg/dL were 0.53 (0.27-1.01) or 0.49 (0.29-0.83), respectively, compared to those with BAC less than 10 mg/dL.

CONCLUSIONS

Analysis of 11850 adult patients showed that having a detectable BAC at hospitalization was associated with significantly decreased odds of 30-day mortality after critical care. Furthermore, BAC greater than 160 mg/dL is associated with significantly decreased odds of developing sepsis and bloodstream infection.