Background: To investigate whether anemia is associated with incident
cardiovascular events and all-cause death among participants who received
intensive blood pressure (BP) treatment in the Systolic Blood Pressure
Intervention Trial (SPRINT). Methods: A total of 4394 participants who
received intensive BP control (systolic BP 120 mmHg) in SPRINT were included.
Anemia status was self-reported. Our primary outcome was a composite of
cardiovascular events, and the secondary outcome was all-cause death. Cox
regression was used to compare the incidence of outcomes between participants
with anemia and non-anemia. In order to balance the baseline characteristics
between the 2 groups, inverse probability of treatment weighting (IPTW) was
applied. Hazard ratios (HRs), along with 95% confidence intervals (CIs), were
then calculated. Results: There were 4394 participants who received
intensive BP control (537 participants with anemia). Participants with anemia
were older (mean age 68.86 versus 67.75, p = 0.01) and more likely to be
female (64.8% versus 31.8%, p 0.001). The presence of anemia was
strongly associated with composite cardiovascular events after adjusting for
potential confounders (HR 1.66, 95% CI 1.18–2.34, p = 0.004). The
association remained statistically significant even in the population after IPTW
(HR 1.55, 95% CI 1.06–2.27, p = 0.024). The secondary outcome revealed
that participants with anemia had a higher rate of all-cause death compared to
those without anemia. The HR of all-cause death for participants with anemia was
1.61 (95% CI 1.00–2.57, p = 0.049) in the population after IPTW.
Conclusions: Anemia appears to be an independent risk factor for
composite cardiovascular events and all-cause death among participants who
received intensive BP control in SPRINT. Clinical Trial Registration:
URL: https://www.clinicaltrials.gov;
Unique identifier: NCT01206062. All SPRINT anonymized data can be found at the
National Heart, Lung and Blood Institute (NHLBI) Biologic Specimen and Data
Repository
(https://biolincc.nhlbi.nih.gov/home/).