Table 2.
Results of risk factors for mortality by multiple regression adjusted for age, gender and race (Model 1) and all risk factors (Model 2) in CKD stages 1–4 with systolic blood pressure (SBP) as a categorical variable.
| CKD Stage 1 | CKD Stage 2 | CKD Stage 3 | CKD Stage 4 | |||||
|---|---|---|---|---|---|---|---|---|
| Model 1 (N = 1428) | Model 2 (N = 1402)* | Model 1 (N = 9306) | Model 2 (N= 9149)* | Model 1 (N = 2471) | Model 2 (N= 2367)* | Model 1 (N = 209) | Model 2 (N = 192)* | |
| Hazard Ratio (P) | Hazard Ratio (P) | Hazard Ratio (P) | Hazard Ratio (P) | Hazard Ratio (P) | Hazard Ratio (P) | Hazard Ratio (P) | Hazard Ratio (P) | |
| SBP<100 (N=491) | 2.04 (0.26) | 1.94 (0.29) | 1.57 (0.03) | 1.48 (0.07) | 1.80 (0.01) | 1.38 (0.21) | 4.03 (0.003) | 3.22 (0.06) |
| SBP 100–120 (N=4027) | Reference | |||||||
| SBP 120–140 (N=4973) | 1.35 (0.32) | 1.33 (0.35) | 0.91 (0.32) | 1.01 (0.92) | 1.11 (0.35) | 1.12 (0.35) | 1.37 (0.34) | 1.49 (0.3) |
| SBP 140–160 (N=2530) | 1.53 (0.18) | 1.42 (0.29) | 0.97 (0.77) | 1.13 (0.24) | 0.94 (0.63) | 0.99 (0.93) | 1.82 (0.07) | 1.96 (0.08) |
| SBP 160–180 (N=943) | 0.95 (0.98) | 0.93 (0.85) | 1.25 (0.05) | 1.44 (0.002) | 1.14 (0.35) | 1.13 (0.43) | 1.94 (0.09) | 1.63 (0.29) |
| SBP>180 (N=450) | 2.75 (0.007) | 2.46 (0.02) | 1.39 (0.02) | 1.50 (0.01) | 1.21 (0.21) | 1.36 (0.06) | 1.40 (0.38) | 1.25 (0.63) |
| Age (per year) | 1.07 (<0.0001) | 1.07 (<0.0001) | 1.10 (<0.001) | 1.09 (<0.0001) | 1.08 (<0.001) | 1.08 (<0.0001) | 1.05 (<0.0001) | 1.05 (<0.001) |
| Sex (Female) | 0.46 (<0.0001) | 0.46 (0.0002) | 0.61 (<0.001) | 0.68 (<0.0001) | 0.68 (<0.001) | 0.71 (<0.0001) | 0.94 (0.74) | 1.25 (0.37) |
| Race (Black) | 0.61 (0.08) | 0.57 (0.06) | 1.42 (0.0001) | 1.27 (0.01) | 1.04 (0.69) | 0.99 (0.89) | 1.16 (0.53) | 1.24 (0.42) |
| Anti-hypertensive medication | 1.42 (0.09) | 1.05 (0.47) | 0.99 (0.92) | 1.34 (0.31) | ||||
| eGFR (per 1 ml/min /1.73m2) | 1.01 (0.68) | 0.99 (<0.05) | 0.98 (<0.001) | 0.95 (0.06) | ||||
| Smoking | 1.76 (0.005) | 2.12 (<0.0001) | 1.71 (0.0014) | 1.24 (0.57) | ||||
| Diabetes | 1.16 (0.49) | 1.33 (<0.001) | 1.34 (0.0004) | 0.95 (0.84) | ||||
| Hyper-lipidemia | 1.25 (0.28) | 0.80 (<0.001) | 0.87 (0.09) | 0.76 (0.26) | ||||
| BMI (per 1 Kg/m2) | 0.96 (0.01) | 0.99 (0.04) | 0.997 (0.71) | 0.96 (0.09) | ||||
| Comorbidities (number) 1 | 1.47 (0.06) | 1.41 (<0.0001) | 1.20 (0.08) | 1.13 (0.78) | ||||
| Comorbidities 2 | 1.55 (0.14) | 1.94 (<0.0001) | 1.43 (0.002) | 0.96 (0.92) | ||||
| Comorbidities 3 | 2.35 (0.04) | 2.16 (<0.0001) | 1.77 (<0.0001) | 1.76 (0.23) | ||||
| Comorbidities 4 | 4.17 (0.06) | 3.99 (<0.0001) | 2.89 (<0.0001) | 1.22 (0.73) | ||||
| Comorbidities 5 | 0.000** (<0.0001) | 3.54 (<0.0001) | 3.05 (<0.0001) | 1.94 (0.24) | ||||
*
The total number of subjects for Model 2 is slightly lower than Model 1 because of subjects that were missing data for adjustment variables.
**
This apparent ‘paradox’ of decreased mortality with 5 comorbidities is likely because there was only one subject with 5 comorbidities in Stage 1 CKD.