Research Article

Prognostic Value of Blood Urea Nitrogen/Creatinine Ratio for Septic Shock: An Analysis of the MIMIC-III Clinical Database

Table 3

Subgroup analysis of the associations between the BCR and 28-day all-cause mortality.

CharacteristicsNo. of patientsBCR for interaction
<14.4≥14.4, <20.0≥20.0, <27.3≥27.3
HR (95% CI)HR (95% CI)HR (95% CI)HR (95% CI)

Age (year)0.104
 <6912281.0 (ref)0.824 (0.590-1.152)0.930 (0.652-1.326)1.165 (0.709-1.914)
 ≥6912561.0 (ref)1.130 (0.828-1.544)0.900 (0.656-1.236)1.275 (0.858-1.896)
Gender0.867
 Male13361.0 (ref)0.831 (0.616-1.121)0.853 (0.630-1.156)0.936 (0.611-1.433)
 Female11481.0 (ref)1.033 (0.733-1.454)0.849 (0.591-1.220)1.206 (0.770-1.889)
Ethnicity0.666
 White18571.0 (ref)0.974 (0.753-1.261)0.886 (0.679-1.155)0.886 (0.679-1.155)
 Black2621.0 (ref)0.843 (0.341-2.041)0.482 (0.191-1.214)0.846 (0.236-3.037)
 Other3651.0 (ref)0.695 (0.381-1.266)0.945 (0.498-1.791)0.631 (0.249-1.600)
Marital status0.980
 Married17741.0 (ref)0.907 (0.700-1.175)0.846 (0.629-1.102)1.144 (0.810-1.616)
 Unmarried6901.0 (ref)0.907 (0.566-1.454)0.866 (0.527-1.423)1.160 (0.594-2.264)
 Other201.0 (ref)
RRT0.065
 Yes2311.0 (ref)0.829 (0.398-1.726)0.585 (0.130-2.263)0.714 (0.147-3.465)
 No22531.0 (ref)1.050 (0.822-1.341)0.982 (0.769-1.255)1.255 (0.913-1.724)
Mech. vent0.484
 Yes14191.0 (ref)0.884 (0.684-1.143)0.812 (0.620-1.064)0.812 (0.620-1.064)
 No10651.0 (ref)1.817 (1.111-2.973)1.732 (1.054-2.847)3.467 (1.833-6.558)
SOFA0.955
 <57461.0 (ref)1.053 (0.578-1.919)0.910 (0.505-1.640)1.240 (0.599-2.564)
 ≥517381.0 (ref)0.946 (0.743-1.204)0.881 (0.685-1.134)1.155 (0.818-1.632)
Elixhauser score0.450
 <1311541.0 (ref)0.665 (0.458-0.964)0.623 (0.422-0.921)0.916 (0.537-1.561)
 ≥1313301.0 (ref)1.150 (0.871-1.518)1.066 (0.800-1.420)1.406 (0.963-2.051)
PT (second)0.007
 <14.912131.0 (ref)0.909 (0.604-1.366)0.943 (0.637-1.397)1.619 (0.995-2.635)
 ≥14.912711.0 (ref)0.992 (0.759-1.298)0.826 (0.642-1.157)0.964 (0.637-1.460)
PTT (second)0.535
 <3212401.0 (ref)1.073 (0.742-1.550)0.965 (0.669-1.391)1.374 (0.866-2.178)
 ≥3212441.0 (ref)0.883 (0.665-1.173)0.813 (0.600-1.101)1.006 (0.662-1.528)
SpO2 (%)0.528
 <9712121.0 (ref)0.894 (0.658-1.214)0.742 (0.532-1.034)1.231 (0.788-1.924)
 ≥9712721.0 (ref)0.976 (0.702-1.357)0.977 (0.704-1.355)1.043 (0.680-1.600)
Temperature (°C)0.118
 <36.711891.0 (ref)1.441 (1.057-1.964)1.087 (0.791-1.495)1.612 (1.070-2.428)
 ≥36.712951.0 (ref)0.657 (0.474-0.910)0.764 (0.546-1.069)0.879 (0.552-1.402)
Heart rate (beats/minute)0.291
 <91.412421.0 (ref)1.008 (0.723-1.407)0.777 (0.547-1.104)1.335 (0.849-2.101)
 ≥91.412421.0 (ref)0.904 (0.671-1.220)0.978 (0.722-1.324)0.985 (0.651-1.489)
MBP (mmHg)0.037
 <70.112341.0 (ref)1.125 (0.837-1.512)0.854 (0.622-1.172)1.422 (0.932-2.171)
 ≥70.112501.0 (ref)0.816 (0.579-1.151)0.958 (0.684-1.341)0.928 (0.587-1.466)
Respiratory rate (beats/minute)0.428
 <21.413361.0 (ref)0.916 (0.667-1.257)0.832 (0.598-1.159)1.482 (0.966-2.274)
 ≥21.411481.0 (ref)0.989 (0.722-1.355)0.825 (0.595-1.145)0.891 (0.562-1.411)
Glucose (mg/dL)0.624
 133.912421.0 (ref)0.971 (0.710-1.327)1.078 (0.781-1.488)1.497 (0.982-2.281)
 ≥133.912421.0 (ref)0.867 (0.626-1.199)0.686 (0.492-0.957)0.808 (0.514-1.268)
Albumin (g/dL)0.451
 <2.711941.0 (ref)1.171 (0.860-1.595)1.083 (0.781-1.500)1.538 (1.004-2.355)
 ≥2.712901.0 (ref)0.826 (0.594-1.148)0.751 (0.542-1.041)1.008 (0.659-1.541)
Bilirubin (mg/dL)0.555
 <0.712291.0 (ref)0.965 (0.676-1.378)0.866 (0.601-1.246)1.173 (0.734-1.874)
 ≥0.712551.0 (ref)0.935 (0.702-1.245)0.848 (0.625-1.151)1.031 (0.679-1.564)
Bicarbonate (mg/dL)0.312
 <2210721.0 (ref)0.965 (0.699-1.332)1.012 (0.712-1.438)1.032 (0.615-1.731)
 ≥2214121.0 (ref)0.937 (0.612-1.288)0.811 (0.593-1.109)1.256 (0.856-1.841)
Calcium (mmol/L)0.981
 <8.111721.0 (ref)0.971 (0.700-1.346)0.891 (0.618-1.285)1.197 (0.717-1.997)
 ≥8.113121.0 (ref)0.899 (0.663-1.217)0.826 (0.611-1.117)1.116 (0.764-1.630)
Potassium (mmol/L)0.231
 <4.211071.0 (ref)0.860 (0.602-1.228)0.888 (0.614-1.285)1.280 (0.759-2.160)
 ≥4.213771.0 (ref)1.053 (0.789-1.406)0.855 (0.635-1.151)1.097 (0.753-1.600)
Sodium (mmol/L)0.098
 <13.812221.0 (ref)0.877 (0.641-1.200)0.765 (0.555-1.055)1.013 (0.652-1.573)
 ≥13.812621.0 (ref)1.016 (0.737-1.402)0.950 (0.681-1.325)1.306 (0.848-2.011)
Hematocrit (%)0.329
 <33.312341.0 (ref)0.935 (0.679-1.285)0.984 (0.712-1.360)1.337 (0.884-2.023)
 ≥33.312501.0 (ref)0.933 (0.681-1.277)0.769 (0.550-1.074)0.928 (0.592-1.455)
Anion gap0.268
 <1510011.0 (ref)0.935 (0.649-1.349)1.234 (0.856-1.777)1.700 (1.052-2.748)
 ≥1514831.0 (ref)0.981 (0.734-1.311)0.797 (0.588-1.080)1.023 (0.690-1.515)
Lymphocytes (%)0.712
 <7.112421.0 (ref)0.837 (0.607-1.154)0.881 (0.635-1.222)1.095 (0.709-1.693)
 ≥7.112421.0 (ref)1.000 (0.730-1.370)0.855 (0.613-1.193)1.171 (0.770-1.781)
Neutrophils (%)0.308
 <81.912191.0 (ref)0.957 (0.684-1.340)0.902 (0.641-1.270)1.357 (0.874-2.107)
 ≥81.912651.0 (ref)0.939 (0.697-1.265)0.914 (0.666-1.254)1.113 (0.719-1.723)
Hours of vasopressor0.013
 <3412231.0 (ref)0.989 (0.693-1.413)0.739 (0.506-1.081)1.268 (0.760-2.117)
 ≥3412611.0 (ref)1.057 (0.872-1.554)1.164 (0.872-1.554)1.306 (0.894-1.910)
Platelet (109/L)0.008
 <21412411.0 (ref)0.782 (0.567-1.079)0.824 (0.595-1.142)1.312 (0.853-2.017)
 ≥21412431.0 (ref)1.062 (0.774-1.457)0.888 (0.641-1.233)0.962 (0.617-1.501)
Hemoglobin (g/dL)0.537
 <10.812041.0 (ref)0.665 (0.462-0.958)0.638 (0.437-0.931)0.931 (0.555-1.560)
 ≥10.812801.0 (ref)1.174 (0.886-1.556)1.014 (0.776-1.396)1.369 (0.932-2.012)
Lactate (mmol/L)0.499
 <1.34091.0 (ref)0.913 (0.510-1.635)0.725 (0.403-1.303)0.766 (0.394-1.486)
 ≥1.320751.0 (ref)1.042 (0.818-1.327)0.942 (0.742-1.195)1.238 (0.968-1.583)
INR0.110
 <1.28981.0 (ref)0.782 (0.529-1.157)0.796 (0.533-1.189)1.108 (0.667-1.841)
 ≥1.215861.0 (ref)1.052 (0.802-1.379)0.874 (0.661-1.157)1.120 (0.768-1.634)
RDW0.552
 <15.412061.0 (ref)0.896 (0.657-1.220)0.735 (0.529-1.022)0.741 (0.472-1.162)
 ≥15.412781.0 (ref)1.014 (0.729-1.409)1.028 (0.735-1.438)1.678 (1.089-2.585)
WBC (109/L)0.091
 <11.912001.0 (ref)0.825 (0.594-1.145)0.802 (0.570-1.128)1.116 (0.720-1.730)
 ≥11.912841.0 (ref)1.149 (0.850-1.553)0.917 (0.673-1.248)1.245 (0.818-1.894)
Chronic pulmonary0.906
 Yes18891.0 (ref)0.954 (0.585-1.554)0.963 (0.580-1.598)1.283 (0.674-2.442)
 No5951.0 (ref)0.922 (0.717-1.185)0.840 (0.647-1.090)1.084 (0.767-1.531)
Cardiac arrhythmias0.095
 Yes10661.0 (ref)0.735 (0.520-1.038)0.754 (0.529-1.076)1.251 (0.789-1.983)
 No14181.0 (ref)1.176 (0.879-1.573)0.988 (0.731-1.335)1.162 (0.776-1.739)
Coagulopathy0.628
 Yes17101.0 (ref)0.783 (0.521-1.177)0.805 (0.534-1.213)1.109 (0.639-1.922)
 No7741.0 (ref)1.098 (0.839-1.438)0.971 (0.733-1.286)1.300 (0.892-1.894)
Congestive heart failure0.352
 Yes9511.0 (ref)0.791 (0.541-1.156)0.876 (0.596-1.287)1.261 (0.739-2.154)
 No15331.0 (ref)0.968 (0.735-1.276)0.856 (0.643-1.141)1.069 (0.744-1.538)
Diabetes0.748
 Yes6011.0 (ref)0.845 (0.487-1.474)1.243 (0.726-2.127)1.368 (0.686-2.727)
 No18831.0 (ref)0.987 (0.773-1.260)0.862 (0.667-1.113)1.100 (0.781-1.549)
Fluid electrolyte0.621
 Yes10341.0 (ref)0.846 (0.628-1.147)0.785 (0.578-1.066)1.006 (0.672-1.507)
 No14501.0 (ref)1.142 (0.820-1.591)1.060 (0.750-1.496)1.462 (0.925-2.312)
Hypertension0.812
 Yes13131.0 (ref)1.085 (0.795-1.481)1.017 (0.737-1.404)1.528 (0.995-2.348)
 No11711.0 (ref)0.922 (0.666-1.275)0.904 (0.644-1.268)1.038 (0.660-1.632)
Liver disease0.792
 Yes5421.0 (ref)0.924 (0.582-1.468)0.999 (0.619-1.611)1.093 (0.596-2.006)
 No19421.0 (ref)0.992 (0.766-1.284)0.891 (0.682-1.164)1.239 (0.862-1.783)
Renal failure0.299
 Yes6161.0 (ref)0.906 (0.624-1.315)0.785 (0.521-1.182)1.049 (0.599-1.835)
 No18681.0 (ref)0.963 (0.727-1.275)1.036 (0.781-1.374)1.402 (0.967-2.034)

BCR: blood urea nitrogen/creatinine ratio; RRT: renal replacement therapy; CHF: congestive heart failure; RDW: red blood cell distribution width; INR: international normal ratio; WBC: white blood cell count; SOFA: Sequential Organ Failure Assessment score.