Table 3.
Renal function changes from baseline to last follow-up by quartiles of the distribution of the follow-up-to-baseline blood lead concentration ratio
| Characteristic | <1.91 | 1.91–3.45 | 3.45–5.66 | ≥5.66 | P value |
|---|---|---|---|---|---|
| Number in group | 62 | 63 | 63 | 63 | … |
| SCRT, mg/dl | 0.0624 (0.0275–0.0973) | 0.0833 (0.0505–0.1160) | 0.0335 (0.0072–0.0742) | 0.0643 (0.0382–0.0903) | 0.57 |
| Serum cystatin C, mg/l | 0.0221 (−0.0054 to 0.0496) | 0.0249 (−0.0041 to 0.0539) | 0.0432 (0.0075–0.0789) | 0.0451 (0.0168–0.0734) | 0.21 |
| eGFRcrt, ml/min per 1.73 m2 | −7.38 (−10.4 to −4.32) | −9.33 (−12.6 to −6.04) | −4.91 (−8.68 to −1.14) | −7.68 (−10.3 to −5.10) | 0.63 |
| eGFRcys, ml/min per 1.73 m2 | −3.12 (−6.08 to −0.17) | −3.70 (−7.00 to −0.40) | −5.19 (−9.38 to −1.00) | −6.04 (−9.45 to −2.63) | 0.20 |
| eGFRcc, ml/min per 1.73 m2 | −5.82 (−8.56 to −3.08) | −6.91 (−9.42 to −4.39) | −5.57 (−8.85 to −2.28) | −7.47 (−10.1 to −4.88) | 0.57 |
| Serum osmolality, mOsm/kg | 2.39 (0.84–3.95) | 2.42 (1.09–3.74) | 1.99 (0.81–3.17) | 2.49 (1.38–3.59) | 0.96 |
| Serum sodium, mmol/l | 1.13 (0.33–1.93) | 0.92 (0.28–1.56) | 0.97 (0.39–1.54) | 1.17 (0.64–1.71) | 0.90 |
| Blood glucose, mg/dl | −4.74 (−9.55 to 0.06) | −5.01 (−9.20 to −0.82) | −8.41 (−13.7 to −3.12) | −5.47 (−10.3 to −0.62) | 0.61 |
| Insulin, % | 37.0 (7.84–74.0) | 8.91 (−15.6 to 40.5) | 19.3 (−5.67 to 50.9) | 28.0 (0.84–62.6) | 0.85 |
| BUN, mg/dl | 1.11 (0.27–1.96) | 2.40 (1.36–3.43) | 1.46 (0.70–2.22) | 1.24 (0.24–2.23) | 0.78 |
| BUN-to-SCRT ratio | 0.31 (−0.67 to 1.29) | 0.95 (−0.12 to 2.01) | 0.99 (0.07–1.90) | 0.11 (−0.94 to 1.15) | 0.80 |
| Urinary gravity, | 0.0044 (0.0023–0.0064) | 0.0028 (0.0005–0.0052) | 0.0009 (−0.0014 to 0.0032) | 0.0027 (0.0007–0.0047) | 0.17 |
| ACR, % | −1.54 (−18.0 to 18.3) | 2.00 (−15.6 to 23.2) | 10.6 (−7.03 to 31.7) | 0.85 (−13.9 to 18.1) | 0.71 |
ACR, albumin-to-creatinine ratio; BUN, blood urea nitrogen; eGFR, estimated glomerular filtration rate; eGFRcc, eGFR derived from SCRT and cystatin C; eGFRcrt, eGFR derived from SCRT; eGFRcys, eGFR derived from cystatin C; IQR, interquartile range; SCRT, serum creatinine.
eGFRcrt, eGFRcys, and eGFRcc refer to the glomerular filtration rate estimated from SCRT, serum cystatin C, or both, respectively.18 Within-group changes are arithmetic mean (SD) or geometric mean (IQR). For logarithmically transformed serum insulin and urinary ACR, changes are expressed as percentage. P values denote the significance of the between-group differences. To convert SCRT to μmol/l, multiply by 88.42; to convert cystatin C from mg/l to nmol/l, multiply by 74.9; to convert blood glucose to mmol/l, multiply by 0.0559; to convert blood urea nitrogen to mmol/l, multiply by 0.3571.