Table 4.
Hazard ratios (95% CI) of all-cause mortality associated with time-varying serum calcium levels and various confounders in unadjusted and multivariable-adjusted Cox models
| Variable | Unadjusted Model | Multivariable-Adjusted Model |
|---|---|---|
| Time-averaged serum calcium | ||
| <9.1 mg/dl | 1.42 (1.15, 1.76) | 1.22 (0.98, 1.53) |
| 9.1 to 9.4 mg/dl (referent) | 1.11 (0.88, 1.40) | 1.08 (0.85, 1.37) |
| 9.41 to 9.7 mg/dl | 1.0 | 1.0 |
| >9.7 mg/dl | 1.25 (0.99, 1.56) | 1.08 (0.86, 1.36) |
| Age, 1 yr older | 1.04 (1.03, 1.05) | |
| Race, black versus white | 0.92 (0.76, 1.13) | |
| CCI, 1 unit higher | 1.06 (1.01, 1.12) | |
| DM, versus no DM | 1.18 (0.99, 1.40) | |
| ASCVD, versus no ASCVD | 1.33 (1.11, 1.58) | |
| SBP | ||
| Linear term, 1 mmHg higher | 0.94 (0.92, 0.97) | |
| Quadratic term, 1 mmHg higher | 1.001 (1.000, 1.002) | |
| DBP, 1 mmHg higher | 1.009 (1.002, 1.016) | |
| Active smoking, versus nonsmoking | 1.39 (1.15, 1.68) | |
| Calcitriol use, versus no use | 0.73 (0.59, 0.91) | |
| Calcium-based binder use, versus no use | 0.79 (0.63, 0.99) | |
| Sevelamer HCl use, versus no use | 0.84 (0.60, 1.18) | |
| Estimated GFR, 1 ml/min per 1.73 m2 higher | 0.989 (0.982, 0.996) | |
| ALP, 1 U/L higher | 1.003 (1.002, 1.004) | |
| Serum phosphorus, 1 mg/dl higher | 1.11 (1.03, 1.20) | |
| Serum bicarbonate | ||
| Linear term, 1 mEq/L higher | 0.78 (0.68, 0.90) | |
| Quadratic term, 1 mEq/L higher | 1.005 (1.002, 1.008) | |
| Blood hemoglobin, 1 g/dl higher | 0.83 (0.79, 0.87) | |
| WBC count, 1000/mm3 higher | 1.08 (1.05, 1.11) | |
| Percent lymphocytes in WBC, 1% higher | 0.97 (0.96, 0.98) | |
| 24 h urine protein, 1 mg higher | 1.04 (0.97, 1.11) | |
| Enrollment period | ||
| 1990 to 1995 | 0.18 (0.09, 0.34) | |
| 1996 to 2000 | 0.84 (0.67, 1.04) | |
| 2001 to 2007 (referent) | 1.0 |
DM, diabetes mellitus; ASCVD, atherosclerotic cardiovascular disease; SBP, systolic blood pressure; DBP, diastolic blood pressure; CCI, Charlson comorbidity index; ALP, alkaline phosphatase.