Table 2. Incidences and hazard ratios of CKD in TBI patients and non-TBI cohort, compared by demographic characteristics and comorbidities.
| Variables | Subjects without TBI | Subjects with TBI | TBI cohort vs. Non-TBI cohort | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Events | Person-years | Incidencea | Events | Person-years | Incidencea | cHR (95% CI) | P value | aHRb (95% CI) | P value | |
| Overall for CKD | 6448 | 871163 | 7.4 (7.22–7.58) | 1966 | 218708 | 8.99 (8.59–9.39) | 1.21 (1.15–1.27) | <0.001 | 1.14 (1.08–1.20) | <0.001 |
| Sex | ||||||||||
| Female | 2586 | 398999 | 6.48 (6.23–6.73) | 776 | 101268 | 7.66 (7.12–8.2) | 1.18 (1.09–1.28) | <0.001 | 1.09 (1.00–1.18) | 0.048 |
| Male | 3862 | 472163.98 | 8.18 (7.92–8.44) | 1190 | 117439.78 | 10.13 (9.56–10.71) | 1.23 (1.15–1.31) | <0.001 | 1.12 (1.05–1.20) | 0.001 |
| Stratify age, years | ||||||||||
| <50 | 1318 | 574236 | 2.3 (2.17–2.42) | 503 | 142850 | 3.52 (3.21–3.83) | 1.53 (1.38–1.70) | <0.001 | 1.23 (1.11–1.37) | <0.001 |
| 50–64 | 1681 | 167057 | 10.06 (9.58–10.54) | 535 | 43157 | 12.4 (11.35–13.45) | 1.23 (1.11–1.35) | <0.001 | 1.12 (1.02–1.24) | 0.024 |
| ≥65 | 3449 | 129870.71 | 26.56 (25.67–27.44) | 928 | 32701 | 28.38 (26.55–30.2) | 1.06 (0.99–1.14) | 0.102 | 1.01 (0.93–1.08) | 0.885 |
| Baseline Comorbidity | ||||||||||
| 0 | 2195 | 666663 | 3.29 (3.15–3.43) | 742 | 165796 | 4.48 (4.15–4.8) | 1.36 (1.25–1.47) | <0.001 | 1.21 (1.11–1.32) | <0.001 |
| 1–2 | 2904 | 164589 | 17.64 (17–18.29) | 874 | 43657 | 20.02 (18.69–21.35) | 1.13 (1.05–1.22) | 0.002 | 1.05 (0.97–1.13) | 0.255 |
| ≥3 | 1349 | 39910.98 | 33.8 (32–35.6) | 350 | 9255 | 37.82 (33.85–41.78) | 1.11 (0.99–1.25) | 0.072 | 1.04 (0.92–1.17) | 0.541 |
| Outpatient visit frequencyc (times per year) | ||||||||||
| ≤12 | 1183 | 445371.98 | 2.66 (2.50–2.81) | 267 | 87698.11 | 3.04 (2.68–3.41) | 1.14 (1.00–1.30) | 0.052 | 1.15 (1.01–1.32) | 0.040 |
| >12 | 5265 | 425791.1 | 12.37 (12.03–12.7) | 1699 | 131010 | 12.97 (12.35–13.59) | 1.05 (0.99–1.11) | 0.089 | 1.11 (1.05–1.17) | <0.001 |
| Monthly income (NTD) | ||||||||||
| <15840 | 3796 | 403923 | 9.4 (9.1–9.7) | 1120 | 114890 | 9.75 (9.18–10.32) | 1.04 (0.97–1.11) | 0.305 | 1.08 (1.01–1.16) | 0.022 |
| 15840–25000 | 1986 | 278773 | 7.12 (6.81–7.44) | 709 | 76497 | 9.27 (8.59–9.95) | 1.3 (1.19–1.41) | <0.001 | 1.16 (1.07–1.27) | <0.001 |
| ≥25000 | 666 | 188467 | 3.53 (3.27–3.8) | 137 | 27322 | 5.01 (4.17–5.85) | 1.42 (1.18–1.7) | <0.001 | 1.18 (0.98–1.42) | 0.085 |
Abbreviations: ACEI, Angiotensin-converting-enzyme inhibitor; aHR, adjusted hazard ratio; ARB, Angiotensin II receptor blocker; CAD, coronary artery disease; cHR, crude hazard ratio; CI, confidence interval; CKD, chronic kidney disease; cHR, crude hazard ratio; NSAIDs, Non-steroidal anti-inflammatory drugs; NTD, new Taiwan dollars; PAOD, peripheral artery occlusive disease; TBI, traumatic brain injury.
aIncidence rate per 1000 person-years.
bResults of multivariate analysis including age, gender, outpatient visit frequency, monthly income, comorbidities (hypertension, diabetes mellitus, hyperlipidemia, CAD, PAOD, arrhythmia, stroke, anemia and gout) and medications (ACEIs/ARBs, anti-gout agents and NSAIDs). Time-dependent covariates were the comorbidities and medications. Competing risks were CKD and death.
cAfter the onset of TBI or index date.