It seems that no ancient treatment is daft enough for some researchers of so-called alternative medicine (SCAM) to not pick it up. Even bloodletting is back, it seems!
The aim of this study was to investigate the effects of therapeutic phlebotomy on ambulatory blood pressure in patients with grade 1 hypertension. In this randomized-controlled intervention study, patients with unmedicated hypertension grade 1 were randomized into an intervention group (phlebotomy group; 500 mL bloodletting at baseline and after 6 weeks) and a control group (waiting list) and followed up for 8 weeks. The primary endpoint was the 24-h ambulatory mean arterial pressure between the intervention and control groups after 8 weeks. Secondary outcome parameters included ambulatory/resting systolic/diastolic blood pressure, heart rate, and selected laboratory parameters (e.g., hemoglobin, hematocrit, erythrocytes, and ferritin). Resting systolic/diastolic blood pressure/heart rate and blood count were also assessed at 6 weeks before the second phlebotomy to ensure safety. A per-protocol analysis was performed.
Fifty-three hypertension participants (56.7 ± 10.5 years) were included in the analysis (n = 25 intervention group, n = 28 control group). The ambulatory measured mean arterial pressure decreased by -1.12 ± 5.16 mmHg in the intervention group and increased by 0.43 ± 3.82 mmHg in the control group (between-group difference: -1.55 ± 4.46, p = 0.22). Hemoglobin, hematocrit, erythrocytes, and ferritin showed more pronounced reductions in the intervention group in comparison with the control group, with significant between-group differences. Subgroup analysis showed trends regarding the effects on different groups classified by serum ferritin concentration, body mass index, age, and sex. Two adverse events (AEs) (anemia and dizziness) occurred in association with the phlebotomy, but no serious AEs.
The authors concluded that therapeutic phlebotomy resulted in only minimal reductions of 24-h ambulatory blood pressure measurement values in patients with unmedicated grade 1 hypertension. Further high-quality clinical studies are warranted, as this finding contradicts the results of other studies.
This paper requires a few short comments:
- The effect on blood pressure was not ‘minimal’, as the authors pretend, it was non-existent (i.e. not significant and due to chance only).
- This lack of effect had to be expected considering human physiology.
- The fact that hemoglobin, hematocrit, erythrocytes, and ferritin all change after bloodletting is equally expected.
- Mild adverse effects are also no surprise.
- What is a surprise, however, that such a trial was ever conducted and passed by an ethics committee. Any medic who has not slept through his/her cardiovascular physiology lectures could have predicted the results quite accurately. And running a trial where the result is well-known before the study has started can hardly be called ethical.