Table I.
Patient characteristics
| Characteristic | Index group (N = 50) (%) | Control group (N = 50) (%) | P value of the difference |
|---|---|---|---|
| Age (Median, IQR)* | 50 (45–59) | 60 (50–66) | 0.01* |
| - < 65 years | 41 (82) | 37 (74) | |
| - ≥ 65 years | 9 (18) | 13 (26) | |
| Sex | NA | ||
| - Female | 50 | 50 | |
| Race | 0.28 | ||
| - Caucasian | 45 (90) | 45 (90) | |
| - Arabic | 4 (8) | 1 (2) | |
| - African | 1 (2) | 1 (2) | |
| - Latino | – | 3 (6) | |
| Breast cancer localization# | 0.54 | ||
| - Left | 25 (50) | 22 (44) | |
| - Right | 23 (46) | 28 (56) | |
| Trastuzumab pretreatment | 0.20 | ||
| - Yes | 8 (16) | 3 (6) | |
| - No | 42 (84) | 47 (94) | |
| Anthracycline pretreatment | 1.0 | ||
| - Doxorubicin | 21 (42) | 17 (34) | |
| - Epirubicin | 19 (38) | 22 (44) | |
| - No | 10 (20) | 11 (22) | |
| Radiotherapy | 0.69 | ||
| - Yes | 26 (52) | 29 (58) | |
| - no | 24 (48) | 21 (42) | |
| Number of drugs | 2 (0–6) | 2 (0–4) | 0.93 |
| Tamoxifen dose | 0.20 | ||
| 20 mg | 45 (90) | 49 (98) | |
| 40 mg | 5 (10) | 1 (2) | |
| Type of antidepressant | NA | ||
| - Venlafaxine | 15 (30) | ||
| - Paroxetine | 10 (20) | ||
| - Escitalopram | 5 (10) | ||
| - Citalopram | 5 (10) | ||
| - Amitriptyline | 5 (10) | ||
| - Sertraline | 4 (8) | ||
| - Fluoxetine | 3 (6) | ||
| Other | 3 (6) | ||
| Renal dysfunction | 1 | 3 | 0.30 |
| Electrolyte disturbances | |||
| - Hyponatremia | 2 | 0 | 0.50 |
| - Hypopotassemia | 0 | 0 | – |
| - Hypocalcemia | 3 | 2 | 1.0 |
| - Hypomagnesemia | 1 | 2 | 1.0 |
| Hepatic dysfunction | 1 | 1 | 1.0 |
| Antidiabetic use | 4 (8) | 3 (6) | 1.0 |
| Loopdiuretic use | 0 (0) | 1 (2) | 1.0 |
Abbrevations: IQR interquartile range, NA not applicable, Other type of antidepressant were fluvoxamine (n = 1), imipramine (n = 1) and nortriptyline (n = 1). Renal dysfunction was defined as estimated Glomerular Filtration Rate (eGFR) < 60 m/min/1,73m2, Hyponatremia was defined as a sodium value < 136 mmol/l, Hypopotassemia was defined as a potassium value < 3.5 mmol/l, hypocalcemia was defined as a calcium value < 2.2 mmol/l, hypomagnesemia was defined as a magnesium value < 0.7 mmol/l and hepatic dysfunction was defined as increased bilirubin (>16umol/l), increased alanine aminotransferase (ALAT) (>40 U/l) or increased aspartate transaminase (ASAT) (>35 U/l). Missing values: Hepatic function (N = 33), Sodium (N = 31), potassium (N = 27), calcium (N = 60), magnesium (N = 66) and renal function (N = 28); * = P value < 0.05. # For breast cancer localization the equation was made for left or right. There was 1 patient with breast cancer on both sides at primary diagnosis and 1 patient for which data regarding tumor localization was unknown due to lack of information from the referring center. These patients were both excluded from this analysis