Table 1.
Baseline Characteristics of Younger and Older Patients With Chronic Heart Failure and Ejection Fraction >45% in the Ancillary Digitalis Investigation Group (DIG) Trial, According to Randomization to Digoxin or Placebo
| Variables, mean (±standard deviation) or n (%) | Age <65 years | Age ≥65 years | ||
|---|---|---|---|---|
|
| ||||
| Placebo (n=176) | Digoxin (n=181) | Placebo (n=320) | Digoxin (n=311) | |
| Age (years)** | 56 (±7) | 56 (±8) | 73 (±6) | 73 (±6) |
| Female** | 64 (36%) | 58 (32%) | 136 (43%) | 149 (48%) |
| Nonwhite** | 30 (17%) | 32 (18%) | 36 (11%) | 39 (13%) |
| Body mass index (kg/m2)** | 30.1 (±7.1) | 30.0 (±7.4) | 27.8 (±5.5) | 27.7 (±5.2) |
| Duration of heart failure (months) | 28 (±33) | 26 (±29) | 29 (±38) | 24 (±30) |
| Left ventricular ejection fraction** | 54 (±8) | 54 (±7) | 56 (±8) | 56 (±9) |
| Cardiothoracic ratio | 0.51 (±0.07) | 0.51 (±0.08) | 0.52 (±0.08) | 0.52 (±0.08) |
| Cardiothoracic ratio >55%** | 41 (23%) | 38 (21%) | 90 (28%) | 94 (30%) |
| New York Heart Association functional class** | ||||
| I | 40 (23%) | 43 (24%) | 62 (19%) | 51 (17%) |
| II | 106 (60%) | 114 (63%) | 176 (55%) | 177 (57%) |
| III | 30 (17%) | 23 (13%) | 74 (23%) | 79 (26%) |
| IV | 0 (0%) | 1 (0.6%) | 8 (3%) | 3 (1%) |
| Signs or symptoms of heart failure | ||||
| Dyspnea at rest | 30 (17%) | 40 (22%) | 71 (22%) | 58 (19%) |
| Dyspnea on exertion | 130 (74%) | 122 (67%) | 242 (76%) | 228 (73%) |
| Jugular venous distension | 11 (6%) | 15 (8%) | 27 (8%) | 28 (9%) |
| Pulmonary râles** | 15 (9%) | 30 (17%)* | 63 (20%) | 47 (15%) |
| Lower extremity edema | 39 (22%) | 48 (27%) | 96 (30%) | 90 (29%) |
| Pulmonary congestion by chest x-ray | 18 (10%) | 18 (10%) | 34 (11%) | 31 (10%) |
| Number of signs or symptoms of heart failure† | ||||
| 0 | 2 (1%) | 2 (1%) | 2 (<1%) | 1 (<1%) |
| 1 | 5 (3%) | 1 (<1%) | 5 (2%) | 5 (2%) |
| 2 | 14 (8%) | 15 (8%) | 18 (6%) | 19 (6%) |
| 3 | 16 (9%) | 12 (7%) | 40 (13%) | 29 (9%) |
| 4 or more | 139 (79%) | 151 (83%) | 255 (80%) | 257 (83%) |
| Prior myocardial infarction | 92 (52%) | 94 (52%) | 153 (48%) | 150 (48%) |
| Current angina pectoris | 44 (25%) | 57 (32%) | 101 (32%) | 92 (30%) |
| Hypertension | 93 (53%) | 111 (61%) | 192 (60%) | 194 (62%) |
| Diabetes mellitus** | 64 (36%) | 54 (30%) | 86 (27%) | 81 (26%) |
| Chronic kidney disease** | 65 (37%) | 55 (30%) | 187 (58%) | 178 (57%) |
| Primary cause of heart failure** | ||||
| Ischemic | 103 (59%) | 104 (58%) | 177 (55%) | 173 (56%) |
| Hypertensive | 27 (15%) | 35 (19%) | 77 (24%) | 83 (27%) |
| Idiopathic | 24 (14%) | 29 (16%) | 29 (9%) | 22 (7%) |
| Others | 22 (13%) | 13 (7%) | 37 (12%) | 33 (11%) |
| Medications | ||||
| Pre–trial digoxin use | 68 (39%) | 60 (33%) | 112 (35%) | 108 (35%) |
| Angiotensin-converting enzyme inhibitors | 160 (91%) | 153 (85%)* | 267 (83%) | 272 (88%) |
| Diuretics** | 131 (74%) | 128 (71%) | 251 (78%) | 241 (78%) |
| Nitrates | 64 (36%) | 66 (37%) | 129 (40%) | 130 (42%) |
| Heart rate (beats per minute)** | 78 (±13) | 76 (±13) | 76 (±12) | 75 (±11) |
| Systolic blood pressure (mm Hg)** | 133 (±22) | 136 (±21) | 138 (±21) | 140 (±21) |
| Diastolic blood pressure (mm Hg)** | 78 (±11) | 79 (±12) | 76 (±11) | 76 (±12) |
| Serum creatinine (mg/dL) | 1.20 (±0.35) | 1.19 (±0.38) | 1.29 (±0.40) | 1.27 (±0.39) |
| Daily dose of study medication, mg** | ||||
| ≤ 0.125 | 16 (9%) | 20 (11%) | 96 (30%) | 90 (29%) |
| 0.25 | 127 (72%) | 119 (66%) | 212 (66%) | 209 (67%) |
| ≥ 0.375 | 33 (19%) | 42 (23%) | 12 (4%) | 12 (4%) |
*
p<0.05 for differences between the two treatment groups.
**
p<0.05 for differences between the two age groups.
†
Clinical signs or symptoms included râles, elevated jugular venous pressure, peripheral edema, dyspnea at rest or on exertion, orthopnea, limitation of activity, S3 gallop, and radiologic evidence of pulmonary congestion present in past or present.