Table 3.
Prespecified subgroup analysis for coprimary endpoints
| Placebo (n=243) | Intravenous iron (n=244) | Treatment effect (95% CI) | Interaction p value | ||
|---|---|---|---|---|---|
| Blood transfusion or death within 30 days | |||||
| Age (years) | |||||
| <70 | 44/156 (28%) | 41/157 (26%) | 0·93 (0·64–1·33) | .. | |
| ≥70 | 23/81 (28%) | 28/80 (35%) | 1·23 (0·78–1·95) | 0·34 | |
| Central laboratory haemoglobin (g/L) | |||||
| <100 | 23/42 (55%) | 23/41 (56%) | 1·02 (0·70–1·51) | .. | |
| ≥100 | 44/187 (24%) | 45/190 (24%) | 1·01 (0·70–1·45) | 0·95 | |
| Sex | |||||
| Female | 42/139 (30%) | 39/122 (32%) | 1·06 (0·74–1·52) | .. | |
| Male | 25/98 (26%) | 30/115 (26%) | 1·02 (0·65–1·62) | 0·91 | |
| Body-mass index (kg/m2) | |||||
| <30 | 52/178 (29%) | 51/161 (32%) | 1·08 (0·79–1·50) | .. | |
| ≥30 | 15/57 (26%) | 18/75 (24%) | 0·91 (0·50–1·65) | 0·62 | |
| Central laboratory ferritin (ng/mL) | |||||
| <100 | 34/132 (26%) | 34/128 (27%) | 1·03 (0·69–1·55) | .. | |
| ≥100 | 32/98 (33%) | 31/94 (33%) | 1·01 (0·67–1·51) | 0·94 | |
| Central laboratory TSAT (%) | |||||
| <20 | 55/174 (32%) | 49/163 (30%) | 0·95 (0·69–1·31) | .. | |
| ≥20 | 8/50 (16%) | 15/53 (28%) | 1·77 (0·82–3·81) | 0·13 | |
| Type of surgery | |||||
| Complex major | 25/83 (30%) | 20/87 (23%) | 0·76 (0·46–1·26) | .. | |
| Major | 17/86 (20%) | 22/85 (26%) | 1·31 (0·75–2·29) | .. | |
| Major plus | 25/68 (37%) | 27/65 (42%) | 1·13 (0·74–1·73) | 0·32 | |
| Blood transfusion episodes within 30 days | |||||
| Age (years) | |||||
| <70 | 0·5 (1·0) | 0·4 (0·8) | 0·79 (0·50–1·24) | .. | |
| ≥70 | 0·4 (0·7) | 0·6 (1·1) | 1·48 (0·79–2·77) | 0·11 | |
| Central laboratory haemoglobin (g/L) | |||||
| <100 | 0·8 (1·1) | 0·8 (1·2) | 1·07 (0·51–2·24) | .. | |
| ≥100 | 0·4 (0·9) | 0·4 (0·8) | 0·93 (0·61–1·41) | 0·74 | |
| Sex | |||||
| Female | 0·5 (0·9) | 0·4 (0·7) | 0·92 (0·55–1·51) | .. | |
| Male | 0·4 (0·9) | 0·5 (1·1) | 1·07 (0·61–1·86) | 0·69 | |
| Body-mass index (kg/m2) | |||||
| <30 | 0·5 (0·9) | 0·5 (1·0) | 1·12 (0·73–1·72) | .. | |
| ≥30 | 0·5 (1·0) | 0·3 (0·6) | 0·68 (0·32–1·42) | 0·25 | |
| Central laboratory ferritin (ng/mL) | |||||
| <100 | 0·5 (1·0) | 0·4 (0·9) | 0·92 (0·55–1·52) | .. | |
| ≥100 | 0·5 (0·8) | 0·5 (0·9) | 1·07 (0·61–1·88) | 0·70 | |
| Central laboratory TSAT (%) | |||||
| <20 | 0·5 (1·0) | 0·5 (1·0) | 0·92 (0·60–1·41) | .. | |
| ≥20 | 0·3 (0·7) | 0·4 (0·7) | 1·55 (0·64–3·75) | 0·29 | |
| Type of surgery | |||||
| Complex major | 0·6 (1·1) | 0·4 (1·0) | 0·77 (0·43–1·40) | .. | |
| Major | 0·3 (0·7) | 0·3 (0·6) | 1·24 (0·62–2·45) | .. | |
| Major plus | 0·6 (0·9) | 0·6 (1·0) | 1·09 (0·57–2·08) | 0·56 | |
Data are n/N (%), mean (SD), risk or rate ratio (95% CI), or p value. Treatment effect is risk ratio for risk of blood transfusion or death within 30 days (first coprimary endpoint) and rate ratio for blood transfusion episodes. TSAT=transferrin saturation.