Table 4.
Full marginal structural models to assess of the association of metabolic acidosis and severe metabolic acidosis with allograft dysfunction, adjusted for baseline and time-varying risk factors for allograft dysfunction
| Marginal structural model (adjusted) | HCO3− < 22 mmol/l |
HCO3− ≤ 18 mmol/l |
||||
|---|---|---|---|---|---|---|
| HR | 95% CI | P value | HR | 95% CI | P value | |
| Metabolic acidosis (exposure) | 1.75 | 1.32–2.31 | <0.001 | 2.09 | 1.23–3.55 | 0.006 |
| Acute rejection (time-varying) | 8.71 | 6.17–12.31 | <0.001 | 9.99 | 7.15–13.98 | <0.001 |
| Systolic BP Z-score Q1 (time-varying) | 0.98 | 0.63–1.52 | 0.918 | 1.16 | 0.77–1.77 | 0.478 |
| Systolic BP Z-score Q4 (time-varying) | 1.50 | 1.11–2.04 | 0.008 | 1.50 | 1.10–2.05 | 0.01 |
| Sex (female) | 0.83 | 0.62–1.11 | 0.210 | 0.87 | 0.66–1.16 | 0.346 |
| Age at KTx | 0.98 | 0.95–1.01 | 0.139 | 0.98 | 0.95–1.01 | 0.111 |
| Body mass index Z-score at KTx | 0.85 | 0.76–0.95 | 0.005 | 0.87 | 0.78–0.98 | 0.017 |
| Donor source (living) | 1.09 | 0.82–1.46 | 0.550 | 1.12 | 0.84–1.50 | 0.433 |
| Transplant sequence | 1.06 | 0.66–1.71 | 0.811 | 1.00 | 0.61–1.64 | 0.998 |
| Year of KTx (beyond 2010) | 0.90 | 0.65–1.25 | 0.523 | 0.83 | 0.59–1.16 | 0.277 |
| Primary kidney disease: glomerular | 0.82 | 0.58–1.16 | 0.264 | 0.91 | 0.65–1.29 | 0.606 |
| Primary kidney disease: tubulointerstitial | 1.02 | 0.71–1.46 | 0.911 | 1.05 | 0.74–1.50 | 0.769 |
| Primary kidney disease: HUS | 0.85 | 0.45–1.61 | 0.618 | 0.87 | 0.45–1.67 | 0.671 |
| Primary kidney disease: vascular complications | 1.48 | 0.70–3.11 | 0.303 | 1.57 | 0.81–3.07 | 0.184 |
| Primary kidney disease: other/unknown | 0.66 | 0.37–1.21 | 0.181 | 0.67 | 0.35–1.26 | 0.208 |
| Number of HLA-MM | 0.99 | 0.90–1.11 | 0.931 | 0.98 | 0.89–1.10 | 0.809 |
| Dialysis vintage (mo) | 1.00 | 0.99–1.01 | 0.877 | 1.00 | 0.99–1.01 | 0.737 |
| Delayed graft function (association with allograft dysfunction within the first year posttransplant) | 1.12 | 0.48–2.62 | 0.794 | 1.1 | 0.49–2.49 | 0.819 |
| Delayed graft function (association with allograft dysfunction beyond 1 year posttransplant) | 1.29 | 0.81–2.06 | 0.298 | 1.34 | 0.82–2.19 | 0.240 |
BP, blood pressure; CI, confidence interval; HLA-MM, human leukocyte antigen mismatch; HR, hazard ratio; HUS, hemolytic uremic syndrome; KTx, kidney transplantation; Q1, first quartile (lowest BP); Q4, fourth quartile (highest BP).