Higher SBP TTR and Lower Risk for Atrial Fibrillation in Patients With Hypertension

An increased systolic blood pressure (SBP) time in target range (TTR) is associated with a reduced risk of incident atrial fibrillation (AF) in patients with hypertension, according to a study in Hypertension.

The post hoc analysis of the SPRINT (Systolic Blood Pressure Intervention Trial; ClinicalTrials.gov Identifier: NCT01206062) trial sought to estimate the association between SBP TTR with incident AF and determine a more appropriate BP control performance measurement for preventing AF.

The multicenter, open-label, randomized controlled SPRINT trial compared the effects of an intensive SBP target of less than 120 mm Hg with a standard SBP target of less than140 mm Hg in patients with hypertension. The current analysis included SPRINT participants with 2 or more follow-up SBP measurements during the first 3 months of the trial and excluded those with missing or uninterpretable baseline ECG results, those without any follow-up ECG results, and those with AF at baseline.

The primary outcome was incident AF, which was the first occurrence of AF measured by standard 12-lead ECG at year 2, year 4, and at a close-out visit in SPRINT. SBP TTR was considered the proportion of time that SBP remains within target range and was calculated with use of Rosendaal linear interpolation method.

The analysis included 7939 participants, with a mean age of 68±9 years who were 35% women. The SBP TTR and mean SBP achieved in the first 3 months among all participants were 59% (IQR, 32%-84%) and 129±12 mm Hg, respectively.

For patients without baseline AF, 187 incident AF cases occurred during a median follow-up of 3.8 years (28,029 person-years; incident rate, 6.7 per 1000 person-years; 95% CI, 5.8-7.7).

Each 10% increase in SBP TTR had a significant association with a reduced risk for incident AF in the unadjusted model and the model adjusted for demographics. After further adjustment for treatment group, medical history, and baseline SBP, a 10% increase in TTR was significantly associated with a 7% decreased risk for incident AF (hazard ratio [HR], 0.93; 95% CI, 0.88-0.97; P =.003).

The fully adjusted model showed that HRs comparing the reference category of TTR of 0% to less than 32% vs TTR of 32% to less than 59%, 59% to less than 84%, and 84% to 100% were 0.82 (95% CI, 0.56-1.20), 0.55 (95% CI, 0.36–0.84), and 0.58 (95% CI, 0.37-0.90), respectively (P value for trend =.003).

Restricted cubic spline curve analysis revealed a linear and inverse association between SBP TTR and incident AF (P_nonlinearity =.338). The risk for AF had a steady decrease with increasing TTR between 0% and 83%.

In a sensitivity analysis, a consistent trend was observed for use of 110 to 140 mm Hg as the SBP target range for both treatment groups. When assessing the sensitivity using TTR in months 0 to 12 instead of months 0 to 3, increased SBP TTR continued to be significantly associated with a reduced risk for incident AF in the fully adjusted model (HR, 0.93 per 10%; 95% CI, 0.88-0.98; P =.010).

Among several limitations, it is possible that some nonpersistent or asymptomatic AF cases were not detected owing to intermittent screening rather than long-term or continuous monitoring. Also, the study excluded patients with diabetes or previous stroke and did not assess the effects of individual drugs and doses on AF.

“Efforts to attain an SBP range within 110 to 140 mm Hg over time may be an effective BP control strategy from the perspective of AF prevention,” wrote the investigators.

Disclosure: Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.