Table 3.
Hazard ratios (95% CI) of all-cause mortality associated with time-averaged 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 | 1.45 (1.17, 1.80) | 1.33 (1.07, 1.66) |
| 9.1 to 9.4 mg/dl (referent) | 1.0 | 1.0 |
| 9.41 to 9.7 mg/dl | 1.12 (0.92, 1.36) | 1.18 (0.96, 1.44) |
| >9.7 mg/dl | 1.31 (1.06, 1.63) | 1.41 (1.13, 1.77) |
| Age, 1 yr older | 1.02 (1.01, 1.03) | |
| Race, black versus white | 0.86 (0.70, 1.05) | |
| CCI, 1 unit higher | 1.09 (1.04, 1.15) | |
| DM, versus no DM | 1.16 (0.98, 1.39) | |
| ASCVD, versus no ASCVD | 1.38 (1.16, 1.64) | |
| SBP | ||
| Linear term, 1 mmHg higher | 0.93 (0.90, 0.96) | |
| Quadratic term, 1 mmHg higher | 1.0002 (1.0001, 1.0003) | |
| DBP, 1 mmHg higher | 0.98 (0.97, 0.99) | |
| Active smoking, versus nonsmoking | 1.41 (1.16, 1.70) | |
| Calcitriol use, versus no use | 0.45 (0.37, 0.54) | |
| Calcium-based binder use, versus no use | 0.79 (0.65, 0.97) | |
| Sevelamer HCl use, versus no use | 0.46 (0.33, 0.63) | |
| Estimated GFR, 1 ml/min per 1.73 m2 higher | 0.989 (0.982, 0.995) | |
| ALP, 1 U/L higher | 1.004 (1.002, 1.005) | |
| Serum phosphorus, 1 mg/dl higher | 1.08 (0.94, 1.24) | |
| Serum bicarbonate | ||
| Linear term, 1 mEq/L higher | 0.53 (0.40, 0.71) | |
| Quadratic term, 1 mEq/L higher | 1.005 (1.001, 1.008) | |
| Blood hemoglobin, 1 g/dl higher | 0.81 (0.76, 0.86) | |
| WBC count, 1000/mm3 higher | 1.06 (1.02, 1.11) | |
| Percent lymphocytes in WBC, 1% higher | 0.984 (0.972, 0.996) | |
| 24 h urine protein, 1 mg higher | 1.05 (0.97, 1.13) | |
| Enrollment period | ||
| 1990 to 1995 | 0.43 (0.32, 0.57) | |
| 1996 to 2000 | 0.78 (0.64, 0.95) | |
| 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.