Table 5.

Mortality HR by dosage in digoxin users

ParameterNUnadjusted Model (HR [95% CI])Covariate- and Propensity Score–Adjusted Model (HR [95% CI])a
Mortality risk by prescribed daily digoxin dosage
    per 62.5-μg/d increase44070.96 (0.90 to 1.02)1.05 (0.99 to 1.12)
    no documented digoxin dosage1421.18 (0.93 to 1.51)1.05 (0.80 to 1.38)
    <55.0 μg/d14661.00 (reference)1.00 (reference)
    55.0 to 62.5 μg/d2730.99 (0.89 to 1.10)0.96 (0.85 to 1.07)
    62.6 to 120.0 μg/d12380.97 (0.81 to 1.16)1.00 (0.83 to 1.21)
    >120.0 μg/d14500.93 (0.84 to 1.03)1.02 (0.91 to 1.14)
    P for trend0.130.42
Mortality risk by baseline serum digoxin level
    per 1-ng/ml increase19851.22 (1.10 to 1.35)1.19 (1.05 to 1.35)
    no digoxin level monitoring25641.12 (0.96 to 1.31)1.05 (0.89 to 1.24)
    <0.6 ng/ml3811.00 (reference)1.00 (reference)
    0.6 to 0.9 ng/ml5521.05 (0.87 to 1.26)1.01 (0.83 to 1.23)
    1.0 to 2.2 ng/ml9731.19 (1.01 to 1.41)1.13 (0.95 to 1.35)
    >2.2 ng/ml791.59 (1.15 to 2.19)1.76 (1.26 to 2.47)
    P for trend0.0010.004
  • aParameters used as baseline covariates in the Cox models and in the propensity score: Age, gender, race (white, black, other), cause of ESRD (diabetes, hypertension, glomerulonephritis, other), systolic and diastolic BP (pre- and postdialysis readings), weight, interdialytic weight gain, access (fistula, graft, catheter, unknown), dialysis adequacy (eKt/V with Kru), Charleson comorbidity index, diabetes status, coronary heart disease, laboratory values (calcium, phosphorus, albumin, hemoglobin, bicarbonate, white blood cell count, creatinine, parathyroid hormone), dialysate K, dialysate calcium, vitamin D use, EPO dosage, study entry date, facility-standardized mortality ratio, oral medication use (angiotensin receptor blocker, angiotensin-converting enzyme inhibitor, nitroglycerine, clopidogrel, aspirin, warfarin, statin, β blocker), ultrafiltration rate, actual dialysis time, and residual renal function.