Table 5.

Mortality HR by dosage in digoxin users

Parameter	N	Unadjusted 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 increase	4407	0.96 (0.90 to 1.02)	1.05 (0.99 to 1.12)
no documented digoxin dosage	142	1.18 (0.93 to 1.51)	1.05 (0.80 to 1.38)
<55.0 μg/d	1466	1.00 (reference)	1.00 (reference)
55.0 to 62.5 μg/d	273	0.99 (0.89 to 1.10)	0.96 (0.85 to 1.07)
62.6 to 120.0 μg/d	1238	0.97 (0.81 to 1.16)	1.00 (0.83 to 1.21)
>120.0 μg/d	1450	0.93 (0.84 to 1.03)	1.02 (0.91 to 1.14)
P for trend		0.13	0.42
Mortality risk by baseline serum digoxin level
per 1-ng/ml increase	1985	1.22 (1.10 to 1.35)	1.19 (1.05 to 1.35)
no digoxin level monitoring	2564	1.12 (0.96 to 1.31)	1.05 (0.89 to 1.24)
<0.6 ng/ml	381	1.00 (reference)	1.00 (reference)
0.6 to 0.9 ng/ml	552	1.05 (0.87 to 1.26)	1.01 (0.83 to 1.23)
1.0 to 2.2 ng/ml	973	1.19 (1.01 to 1.41)	1.13 (0.95 to 1.35)
>2.2 ng/ml	79	1.59 (1.15 to 2.19)	1.76 (1.26 to 2.47)
P for trend		0.001	0.004

^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.