Association Between Blood Pressure Control and Risk of Recurrent Intracerebral Hemorrhage

Abstract

Importance: Intracerebral hemorrhage (ICH) is the most severe form of stroke. Survivors are at high risk of recurrence, death, and worsening functional disability.

Objective: To investigate the association between blood pressure (BP) after index ICH and risk of recurrent ICH.

Design, setting, and participants: Single-site, tertiary care referral center observational study of 1145 of 2197 consecutive patients with ICH presenting from July 1994 to December 2013. A total of 1145 patients with ICH survived at least 90 days and were followed up through December 2013 (median follow-up of 36.8 months [minimum, 9.8 months]).

Exposures: Blood pressure measurements at 3, 6, 9, and 12 months, and every 6 months thereafter, obtained from medical personnel (inpatient hospital or outpatient clinic medical or nursing staff) or via patient self-report. Exposure was characterized in 3 ways: (1) recorded systolic and diastolic measurements; (2) classification as adequate or inadequate BP control based on American Heart Association/American Stroke Association recommendations; and (3) stage of hypertension based on Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure 7 criteria.

Main outcomes and measures: Recurrent ICH and its location within the brain (lobar vs nonlobar).

Results: There were 102 recurrent ICH events among 505 survivors of lobar ICH and 44 recurrent ICH events among 640 survivors of nonlobar ICH. During follow-up adequate BP control was achieved on at least 1 measurement by 625 patients (54.6% of total [range, 49.2%-58.7%]) and consistently (ie, at all available time points) by 495 patients (43.2% of total [range, 34.5%-51.0%]). The event rate for lobar ICH was 84 per 1000 person-years among patients with inadequate BP control compared with 49 per 1000 person-years among patients with adequate BP control. For nonlobar ICH the event rate was 52 per 1000 person-years with inadequate BP control compared with 27 per 1000 person-years for patients with adequate BP control. In analyses modeling BP control as a time-varying variable, inadequate BP control was associated with higher risk of recurrence of both lobar ICH (hazard ratio [HR], 3.53 [95% CI, 1.65-7.54]) and nonlobar ICH (HR, 4.23 [95% CI, 1.02-17.52]). Systolic BP during follow-up was associated with increased risk of both lobar ICH recurrence (HR, 1.33 per 10-mm Hg increase [95% CI, 1.02-1.76]) and nonlobar ICH recurrence (HR, 1.54 [95% CI, 1.03-2.30]). Diastolic BP was associated with increased risk of nonlobar ICH recurrence (HR, 1.21 per 10-mm Hg increase [95% CI, 1.01-1.47]) but not with lobar ICH recurrence (HR, 1.36 [95% CI, 0.90-2.10]).

Conclusions and relevance: In this observational single-center cohort study of ICH survivors, reported BP measurements suggesting inadequate BP control during follow-up were associated with higher risk of both lobar and nonlobar ICH recurrence. These data suggest that randomized clinical trials are needed to address the benefits and risks of stricter BP control in ICH survivors.

Figure 1

Participant Enrollment and Sequential Application of Eligibility and Exclusion Criteria Leading to Definition of Final Study Population

Figure 2. Estimated Yearly Risk of Recurrent ICH Based on Mean Blood Pressure Measurements During Follow-up

Box upper and lower margins indicate 25th and 75th percentiles of risk distributions, respectively; heavy horizontal lines in boxes indicate median risk values; error bars indicate maximum and minimum estimated risk values in each distribution. Vertical lines in blue indicate currently recommended blood pressure (BP) control goals among survivors of intracerebral hemorrhage (ICH) without diabetes, based on American Heart Association/American Stroke Association guidelines for post-ICH secondary prevention (lines are added for illustrative purposes only and have no direct impact on risk estimation results). A, Estimated yearly risk of recurrent lobar ICH based on systolic and diastolic BP measurements during follow-up. Estimated risk calculated adjusting for other factors associated with recurrence of lobar ICH (see main text and eMethods in the Supplement). B, Estimated yearly risk of recurrent nonlobar ICH based on systolic and diastolic BP measurements during follow-up. Risk is calculated assuming mean systolic and diastolic BP measurements as indicated on the horizontal axes and is expressed as % recurrent rate/y among survivors of nonlobar ICH. Estimated risk calculated adjusting for other factors associated with recurrence of nonlobar ICH (see main text and eTable 2 in the Supplement).