To assess the association between low serum creatinine value at admission and in-hospital mortality in hospitalized patients.
This was a retrospective single-center cohort study conducted at a tertiary referral hospital. All hospitalized adult patients in 2011 through 2013 who had an admission creatinine value available were identified for inclusion in this study. Admission creatinine value was categorized into 7 groups: ≤0.4, 0.5-0.6, 0.7-0.8, 0.9-1.0, 1.1-1.2, 1.3-1.4, and ≥1.5 mg/dL. The primary outcome was in-hospital mortality. Logistic regression analysis was performed to obtain the odds ratio of in-hospital mortality for the various admission creatinine levels, using creatinine value of 0.7-0.8 mg/dL as the reference group in analysis of all patient and females and of 0.9-1.0 mg/dL in analysis of males because it was associated with lowest in-hospital mortality.
Of 73,994 included patients, 973 (1.3%) died in the hospital. The association between different categories of admission creatinine value and in-hospital mortality assumed a U-shaped distribution, with both low and high creatinine values associated with higher in-hospital mortality. After adjustment for age, sex, ethnicity, principal diagnosis, and comorbid conditions, very low creatinine value (≤0.4 mg/dL) was significantly associated with increased mortality (odds ratio, 3.29; 95% CI, 2.08-5.00), exceeding the risk related to markedly increased creatinine value of ≥1.5 mg/dL (odds ratio, 2.56; 95% CI, 2.07-3.17). The association remained significant in subgroup analysis of male and female patients.
Low creatinine value at admission is independently associated with increased in-hospital mortality in hospitalized patients.