Table 2:
Association between cystatin C–based eGFR and stroke with Cox proportional hazards models.
| Crude model | Fully adjusted model | |||||
|---|---|---|---|---|---|---|
| eGFRcys | Incidence rate, per 100 000 person-years | Events (%) | HRs (95% CIs) | RDR-adjusted HRs (95% CIs) | HRs (95% CIs) | RDR-adjusted HRs (95% CIs) |
| Total stroke | ||||||
| Continuous, 10 mL/min/1.73 m2 decrement | 103.5 | 4427 (1.03) | 1.39 (1.37–1.41) | 1.43 (1.41–1.47) | 1.09 (1.05–1.12) | 1.10 (1.05–1.14) |
| Binary | ||||||
| ≥60 mL/min/1.73 m2 | 94.4 | 3879 (0.94) | Reference | Reference | Reference | Reference |
| <60 mL/min/1.73 m2 | 327.9 | 548 (3.09) | 3.45 (3.16–3.77) | 3.89 (3.52–4.29) | 1.31 (1.14–1.50) | 1.34 (1.15–1.56) |
| Multicategory | ||||||
| >105 mL/min/1.73 m2 | 41.0 | 298 (0.41) | 0.55 (0.48–0.63) | 0.52 (0.45–0.60) | 0.82 (0.69–0.98) | 0.80 (0.67–0.98) |
| 90–105 mL/min/1.73 m2 | 74.5 | 1054 (0.75) | Reference | Reference | Reference | Reference |
| 75–<90 mL/min/1.73 m2 | 103.9 | 1358 (1.03) | 1.39 (1.29–1.51) | 1.44 (1.32–1.57) | 1.01 (0.91–1.12) | 1.01 (0.90–1.13) |
| 60–<75 mL/min/1.73 m2 | 177.3 | 1169 (1.74) | 2.37 (2.18–2.57) | 2.57 (2.35–2.82) | 1.24 (1.10–1.39) | 1.27 (1.11–1.43) |
| <60 mL/min/1.73 m2 | 327.9 | 548 (3.09) | 4.37 (3.94–4.84) | 5.03 (4.49–5.64) | 1.44 (1.23–1.69) | 1.49 (1.25–1.78) |
| Ischemic stroke | ||||||
| Continuous, 10 mL/min/1.73 m2 decrement | 80.6 | 3447 (0.80) | 1.45 (1.43–1.47) | 1.49 (1.47–1.54) | 1.10 (1.06–1.14) | 1.11 (1.08–1.15) |
| Binary | ||||||
| ≥60 mL/min/1.73 m2 | 72.5 | 2981 (0.72) | Reference | Reference | Reference | Reference |
| <60 mL/min/1.73 m2 | 278.5 | 466 (2.63) | 3.82 (3.46–4.21) | 4.34 (3.90–4.83) | 1.30 (1.12–1.51) | 1.33 (1.13–1.57) |
| Multicategory | ||||||
| >105 mL/min/1.73 m2 | 27.9 | 203 (0.28) | 0.53 (0.45–0.62) | 0.50 (0.42–0.59) | 0.81 (0.66–1.00) | 0.79 (0.63–1.00) |
| 90-105 mL/min/1.73 m2 | 52.8 | 747 (0.53) | Reference | Reference | Reference | Reference |
| 75–<90 mL/min/1.73 m2 | 81.8 | 1070 (0.81) | 1.55 (1.41–1.70) | 1.62 (1.46–1.79) | 1.08 (0.96–1.22) | 1.09 (0.96–1.24) |
| 60–<75 mL/min/1.73 m2 | 145.6 | 961 (1.43) | 2.75 (2.50–3.02) | 3.03 (2.73–3.36) | 1.29 (1.13–1.48) | 1.32 (1.14–1.54) |
| <60 mL/min/1.73 m2 | 278.5 | 466 (2.63) | 5.24 (4.67–5.88) | 6.14 (5.41–6.97) | 1.51 (1.26–1.80) | 1.57 (1.29–1.90) |
| Hemorrhagic stroke | ||||||
| Continuous, 10 mL/min/1.73 m2 decrement | 27.1 | 1163 (0.27) | 1.23 (1.20–1.28) | 1.27 (1.22–1.32) | 1.03 (0.97–1.09) | 1.03 (0.97–1.10) |
| Binary | ||||||
| ≥60 mL/min/1.73 m2 | 25.6 | 1054 (0.26) | Reference | Reference | Reference | Reference |
| <60 mL/min/1.73 m2 | 64.5 | 109 (0.62) | 2.51 (2.06–3.05) | 2.74 (2.20–3.40) | 1.25 (0.93–1.69) | 1.28 (0.92–1.78) |
| Multicategory | ||||||
| >105 mL/min/1.73 m2 | 14.1 | 103 (0.14) | 0.58 (0.46–0.72) | 0.55 (0.43–0.70) | 0.80 (0.60–1.07) | 0.78 (0.57–1.08) |
| 90–105 mL/min/1.73 m2 | 24.5 | 347 (0.25) | Reference | Reference | Reference | Reference |
| 75–<90 mL/min/1.73 m2 | 25.5 | 335 (0.26) | 1.04 (0.90–1.21) | 1.05 (0.89–1.23) | 0.82 (0.67–1.00) | 0.80 (0.64–1.00) |
| 60–<75 mL/min/1.73 m2 | 40.5 | 269 (0.40) | 1.65 (1.41–1.93) | 1.73 (1.45–2.06) | 1.08 (0.86–1.35) | 1.09 (0.85–1.39) |
| <60 mL/min/1.73 m2 | 64.5 | 109 (0.62) | 2.62 (2.11–3.25) | 2.87 (2.27–3.63) | 1.20 (0.86–1.67) | 1.22 (0.85–1.75) |
Covariates in the fully adjusted model included age, sex, ethnicity, education, Townsend deprivation index, smoking status, alcohol consumption, metabolic equivalents, BMI, systolic blood pressure, diastolic blood pressure, glycated hemoglobin A1c, low-density lipoprotein, high-density lipoprotein, triglycerides, C-reactive protein, urine albumin-to-creatinine ratio, hypertension, diabetes, cardiovascular diseases, antihypertensive medications, hypoglycemic agents, lipid-lowering drugs and antiplatelet drugs. The regression dilution ratio was 0.91.
The proportional hazards assumption was checked for all the models using statistical tests and graphical diagnostics based on the scaled Schoenfeld residuals. Time-dependent covariates were constructed in those where the proportional hazards assumption was violated (diastolic blood pressure in the models for total stroke; systolic blood pressure and diastolic blood pressure in the models for ischemic stroke; C-reactive protein in the models for hemorrhagic stroke). Variance inflation factor values were below 5 for all the models presented, indicating a low risk of multicollinearity.
eGFRcys, estimated glomerular filtration rate based on serum cystatin C calculated with the Chronic Kidney Disease Epidemiology Collaboration equation.