Table 2.
Outcomes of patients with heart failure with reduced ejection fraction treated with vs. without digoxin
| Patients with AF | Patients without AF | |||||||
|---|---|---|---|---|---|---|---|---|
| Model | Overall Population | Matched population | Overall population | Matched population | ||||
| Digoxin no | Digoxin yes | Digoxin no | Digoxin yes | Digoxin no | Digoxin yes | Digoxin no | Digoxin yes | |
| All-cause death/first heart failure hospitalization | ||||||||
| Incidence [n of events, sum py, rate/1000py (95% CI)] | 10 162, 36 835, 276 (271–281) | 4209, 18 673, 225 (219–232) | 4156, 16 901, 246 (238–253) | 4117, 18 056, 228 (221–235) | 11 261, 59 188, 190 (187–194) | 456, 1484, 307 (280–337) | 418, 1708, 245 (222–269) | 452, 1483, 305 (277–334) |
| Crude HR (95% CI), P-value | Ref. | 0.88 (0.85–0.91), <0.001 | Ref. | 1.63(1.49–1.79) <0.001 | ||||
| Adj. (PS) HR (95% CI), P-value | Ref. | 0.98 (0.94–1.01), 0.225 | Ref. | 0.95 (0.91–0.99), 0.011 | Ref. | 1.16 (1.05–1.28), 0.003 | Ref. | 1.24 (1.09–1.43), 0.002 |
| Consistency (digoxin time-dependent) | Ref. | 0.82 (0.76–0.86), <0.001 | Ref. | 1.25 (1.08–1.45), 0.003 | ||||
| All-cause death | ||||||||
| Incidence [n of events, sum py, rate/1000py (95% CI)] | 7948, 52 676, 151 (148–154) | 3372, 25 858, 130 (126-135) | 3171, 24 835, 128 (123–132) | 3298, 24989, 132 (128-137) | 7889, 81 881, 96 (94–98) | 349, 2644, 132 (119–147) | 324, 2618, 124 (111–138) | 346, 2620, 132 (119–147) |
| Crude HR (95% CI), P-value | Ref. | 0.88 (0.84–0.91), <0.001 | Ref. | 1.39 (1.25–1.54), <0.001 | ||||
| Adj. (PS) HR (95% CI), P-value | Ref. | 1.06 (1.02–1.11), 0.007 | Ref. | 1.03 (0.99–1.09), 0.173 | Ref. | 1.08 (0.96–1.21), 0.182 | Ref. | 1.07 (0.92–1.25), 0.382 |
| Consistency (digoxin time dependent) | Ref. | 0.80 (0.76–0.84), <0.001 | Ref. | 1.04 (0.89–1.22), 0.604 | ||||
| First heart failure hospitalization | ||||||||
| Incidence [n of events, sum py, rate/1000py (95% CI)] | 6785, 36 835, 184 (180–189) | 2828, 18 673, 151 (146–157) | 2872, 16 901, 170 (164–176) | 2768, 18 056, 153 (148–159) | 7520, 59 188, 127 (124–130) | 344, 1484, 232 (208–258) | 291, 1708, 170 (151–191) | 340, 1483, 229 (206–255) |
| Crude HR (95% CI), P-value | Ref. | 0.91 (0.87–0.95), <0.001 | Ref. | 1.85 (1.66–2.07), <0.001 | ||||
| Adj. (PS) HR (95% CI), P-value | Ref. | 0.96 (0.92–1.01), 0.089 | Ref. | 0.93 (0.88–0.98), 0.004 | Ref. | 1.24 (1.11–1.39), <0.001 | Ref. | 1.34 (1.14–1.57), <0.001 |
| Consistency (digoxin time dependent) | Ref. | 0.81 (0.77–0.85), <0.001 | Ref. | 1.42 (1.19–1.69), <0.001 | ||||
| Consistency (death as competing event) | Ref. | 0.93 (0.89–0.98), 0.009 | Ref. | 1.28 (1.09–1.49), 0.002 | ||||
AF, atrial fibrillation; CI, confidence interval; HR, hazard ratio; PS, propensity score; py, patient-years; and ref, reference.
aPropensity scores (PSs) for digoxin use were separately calculated in each imputed data set by a logistic regression model including all the variables highlighted in Table 1 as covariates, and then averaged across the 10 imputed data sets, for patients with and without AF. Adjusted Cox regression models were performed partly in the PS-matched cohort and partly in the overall cohort including the PS as a covariate.