Table 1

Baseline characteristics of the entire cohort, according to the presence of ID, and of the healthy volunteers

Variables, unitsPatients with severe aortic stenosisHealthy volunteers (n=50)
All patients (n=464)Severe AS and ID* (n=246)Severe AS and no ID* (n=218)P value for difference
Demography
 Age, years75 (11)76 (10)74 (11)0.01167 (8)‡
 Female sex, n (%)202 (44)133 (54)69 (32)<0.00118 (36)
 Body mass index, kg/m226 (5)26 (5)26 (4)0.88925 (3)
 Current smoker, n (%)59 (13)33 (13)26 (12)0.631
Medical history, n (%)
 Hypertension208 (45)108 (44)100 (46)0.670
 Heart failure34 (7)21 (9)13 (6)0.288
 Atrial fibrillation/flutter, all types106 (23)58 (24)48 (22)0.690
 Diabetes mellitus type I and II57 (12)37 (15)20 (9)0.055
 Pulmonary disease87 (19)48 (20)39 (18)0.672
 Kidney disease, eGFR <60 mL/min/1.73 m231 (7)17 (7)14 (6)0.833
 Coronary artery disease150 (32)86 (35)64 (29)0.198
 Malignancy (previous/active)58 (13)37 (15)21 (10)0.079
Medication, n (%)
 Beta blocker223 (48)122 (50)101 (46)0.483
 ACEi/ARB186 (40)87 (35)99 (45)0.028
 Calcium antagonist92 (20)47 (19)45 (21)0.679
 Statin249 (54)127 (52)122 (56)0.350
 Diuretic176 (38)90 (37)86 (39)0.526
 Anticoagulants/antiplatelets336 (72)174 (71)162 (74)0.389
 Antacids/PPI46 (14)45 (18)19 (9)0.003
Clinical findings
 Systolic blood pressure, mm Hg143 (23)144 (23)142 (23)0.327
 Diastolic blood pressure, mm Hg77 (12)77 (13)77 (11)0.325
 Heart rate, beats/min73 (13)73 (14)72 (12)0.979
Surgical risk score
 EuroSCORE II3 (1–5)3 (2–5)2 (1–4)0.003
Six-minute walk test, meters436 (136)413 (133)467 (135)0.002
Health-related quality of life
 Summary PCS (sf36-v2)38 (11)37 (11)40 (10)0.008
 Summary MCS (sf36-v2)50 (12)49 (12)50 (12)0.904
 EQ-5D UK index score, median (IQR)0.70 (0.63–0.77)0.71 (0.66–0.77)0.70 (0.60–0.77)0.160
 EQ-VAS score58 (22)57 (22)60 (21)0.061
Cognitive ability
 MMSE, median (IQR)29 (28–30)29 (27–30)29 (28–29)0.926
Charlson comorbidity index, n (%)0.131
 0177 (38)85 (35)92 (42)
 1–2226 (49)123 (50)103 (47)
 ≥361 (13)38 (15)23 (11)
NYHA classification, n (%)0.636
 Class I51 (11)24 (10)27 (12)
 Class II200 (43)106 (43)94 (43)
 Class III/IV213 (46)116 (47)97 (45)
CCS, angina grade, n (%)0.166
 Score 0263 (57)140 (57)123 (57)
 Score 1–2172 (37)86 (35)86 (39)
 Score 3–429 (6)20 (8)9 (4)
Echocardiographic measures
 BSA1.88 (0.22)1.85 (0.22)1.92 (0.22)<0.001
 LVEF, %56 (9)56 (9)57 (9)0.301
 Aortic peak velocity, m/s4.7 (07)4.7 (0.7)4.7 (0.7)0.766
 Aortic mean gradient, mm Hg55 (18)55 (18)55 (18)0.876
 Aortic valve area, cm20.67 (0.20)0.63 (0.17)0.72 (0.23)<0.001
Biochemistry
 Haemoglobin, g/dL13.6 (1.6)13.2 (1.6)14.0 (1.5)<0.00114.3 (0.9)‡
 NT-pro-BNP, pmol/L, median (IQR)102 (36–252)115 (44–258)72 (29–241)0.0118 (8–28)‡
 hs-TnT, ng/mL, median (IQR)14 (10–25)14 (10–27)12 (10–25)0.188
 Creatinine, µmol/L, median (IQR)81 (68–99)82 (67–101)81 (69–95)0.600
 CRP, mg/L, median (IQR)2.1 (0.8–5.4)2.4 (0.8–6.3)1.8 (0.7–4.9)0.093
 Ferritin, µg/L, median (IQR)117 (66–197)69 (41–93)187 (136–280)<0.001
 Transferrin, g/L2.6 (0.7)2.7 (0.9)2.4 (0.4)<0.001
 Iron, µmol/L, median (IQR)14 (11–19)11 (9–15)17 (14–20)<0.001
 Total iron binding capacity (TIBC)64 (11)67 (11)50 (9)<0.001
 Transferrin saturation (TSAT) (%) median (IQR)23 (17–30)18 (13–23)28 (24–34)<0.001
 Hepcidin, ng/mL, median (IQR)36.2 (16.4–59.3)22.3 (11.2–44.9)51.4 (29.0–71.4)<0.00116.0 (6.4–41.5) ‡
 Transferrin receptor, ng/mL, median (IQR)777 (620–1005883 (689–1158703 (573–848)<0.001744 (619–950)
Presence of anaemia, n (%)94 (20)59 (24)35 (16)0.029
Presence of ferritin <30 µg/L, n (%)31 (7)31 (13)0 (0)<0.001
Presence of ID, n (%)*246 (53)246 (100)0 (0)<0.001
 Absolute (ferritin <100 µg/L), n (%)195 (42)195 (79)0 (0)<0.001
 Functional (ferritin 100–300 µg/L and low TSAT (<20%)), n (%)51 (11)51 (21)0 (0)<0.001
  • Selected characteristics of the study sample (n=464). The numbers are mean (SD), frequency (%) or medians (IQR). Complete data of ferritin, transferrin, iron, total iron binding capacity (TIBC), transferrin saturation (TSAT) and hepcidin. Other numbers may vary due to missing values. P-values for comparison of results of patients with ID and those without ID.

  • *ID was defined as ferritin level <100 µg/L or ferritin 100–299 µg/L with a transferrin saturation <20%.

  • †Anaemia was defined as haemoglobin level <12 g/dL in women and <13 g/dL in men.

  • ‡P<0.001, patients with severe AS (all patients) compared with healthy subjects.

  • ACEi, ACE inhibitor; ARB, angiotensin receptor blocker; AS, Aortic stenosis; BSA, body surface area; CCS, Canadian Cardiovascular Society; CRP, C-reactive protein; EQ-5D UK, EuroQol 5-dimension United Kingdom; EQ-VAS, EuroQol Visual Analogue Scale; ID, Iron deficiency; LVEF, left ventricular ejection fraction; MCS, Mental Component Summary; MMSE, Mini-Mental State Examination; NT-proBNP, N-terminal pro-B-type natriuretic peptide; NYHA, New York Heart Association; PCS, Physical Component Summary; PPI, proton-pump inhibitor; eGFR, estimated glomerular filtration rate; hsTNT, high-sensitive troponin T; sf36-v2, Short Form Health Survey version 2.0.