Table 5.
Clinical studies assessing the association between hemoglobin concentrations, anemia, or transfusion and subsequent outcomes among patients with aneurysmal subarachnoid hemorrhage
| Study | Patients | Design and setting | Exposure | Mean pre-transfusion Hb/Hct | Analysis (variables) | Main result |
| ‡Kramer and colleagues [28] | 245 | Retrospective Single-center |
- Anemia (nadir Hb <10 g/dl) - RBC transfusion (35%) |
9.5 g/dl No transfusion protocol |
Logistic regression (WFNS score, age, vasospasm, modified Fisher score) | - Anemia and transfusion associated with poor 6 week outcome (association stronger for transfusion) - RBCs associated with nosocomial infection - Age of blood not associated with complications |
| ‡Kramer and colleagues [154] | 245 | Retrospective Single-center |
Daily nadir Hb over 2 weeks | 9.5 g/dl No transfusion protocol |
GEE to account for correlated data (WFNS score, age, vasospasm, modified Fisher score) | - Hb and decline in Hb over time predict poor outcome - Association between Hb and outcome stronger among high grade patients |
| †Naidech and colleagues [155] | 611 | Retrospective (prospective database) Single-center |
- Mean and nadir Hb over 2 weeks - 35% transfused |
Not reported No transfusion protocol |
Multinomial regression (Hunt-Hess, age, cerebral infarction) | Higher nadir (but not mean) Hb associated with better outcome after 3 months (OR = 0.83 per 10 g/dl increase; P = 0.04) |
| Naidech and colleagues [156] | 103 | Retrospective (prospective database) Single-center |
- Mean Hb over 2 weeks - 47% transfused |
9.2 g/dl No transfusion protocol |
Logistic regression (Hunt-Hess, age, angiographic vasospasm) | Higher 2 week mean Hb associated with better outcome at discharge (OR = 0.57 per 10 g/dl increase; P = 0.04) |
| Tseng and colleagues [157] | 160 |
Post hoc analysis 2 RCTs) Single-center |
RBC transfusion (19%) | Not reported | Logistic regression (age, WFNS, IVH, postoperative deficits, sepsis, DIDs) | - Transfusion associated with poor outcome at discharge (OR = 4.5, P = 0.04) but not 6 months - More colloid use predicted lower hct and need for transfusion |
| †Wartenberg and colleagues [158] | 576 | Retrospective (prospective database) Single-center |
Anemia (Hb <9 g/dl treated with transfusion; 36% of cohort) | Not reported No transfusion protocol |
Logistic regression (Hunt-Hess, age, cerebral infarction, re-bleeding, aneurysm size >10 mm) | Anemia associated with worse 3 month outcome (OR = 1.8; P = 0.02) |
| * DeGeorgia and colleagues [159] | 166 | Retrospective Single-center |
RBC Transfusion (49%) | Not reported No transfusion protocol |
Logistic regression (Hunt-Hess, APACHE II) | Transfusion associated with worse outcome at discharge among patients with vasospasm, not without (OR = 2.9, CI = 1.1 to 7.8) |
| Smith and colleagues [160] | 441 | Retrospective (prospective database) Single-center |
RBC transfusion (61%) | Intra-operative: 39.6% Post-operative: 32.0% No transfusion protocol |
Logistic regression (Hunt-Hess, Fisher, smoking, intra-operative rupture, delay to surgery) | - Intraoperative transfusion associated with poor 6 month outcome (OR = 2.4, CI = 1.3 to 4.5) - Postoperative transfusion associated with angiographic vasospasm (OR = 1.7, CI = 1.0 to 2.8)) |
‡ & †: studies used same datasets; *: published only as abstract
APACHE = Acute Physiology and Chronic Health Evaluation; CI = 95% confidence intervals; DID = delayed ischemic deficit; GEE = generalized estimating equation; Hb = hemoglobin; hct = hematocrit; IVH = intraventricular hemorrhage; OR = odds ratio; RBC = red blood cell; RCT = randomized controlled trial; WFNS = World Federation of Neurological Surgeons score.