Rethinking Blood Pressure Quality Measurement: Accounting for Seasonal Variation in Value-Based Care

Area of Science:

• Cardiology
• Public Health
• Health Informatics

Background:

• Value-based care (VBC) emphasizes quality metrics like blood pressure (BP) control.
• The Healthcare Effectiveness Data and Information Set (HEDIS) Controlling High Blood Pressure (CBP) measure uses a single year-end BP reading.
• This method overlooks seasonal BP variations, where BP naturally declines in summer and rises in winter.

Purpose of the Study:

• To evaluate the impact of seasonal BP variations on measured performance within a large health system.
• To compare the accuracy of year-end BP readings versus a rolling average for assessing BP control.
• To advocate for improved quality measurement methods that account for seasonal BP fluctuations.

Main Methods:

• Retrospective analysis of monthly BP control rates from July 2019 to December 2025 (78 months) in the Jefferson Health-Lehigh ambulatory network.
• Comparison of summer (June-August) and winter (December-February) BP control rates using paired t-tests and regression analysis.
• Assessment of year-end performance using both the HEDIS December-only rate and a rolling Q4 (October-December) average.

Main Results:

• BP control rates were significantly higher in summer (75.2%) than in winter (73.1%), a 2.1-percentage-point difference.
• This seasonal pattern was consistent across all 7 years of the study.
• The rolling Q4 average consistently exceeded the December-only rate, reclassifying 60-520 additional patients as controlled annually.

Conclusions:

• Seasonal BP variation is a robust phenomenon that is inadequately addressed by current quality measures like HEDIS CBP.
• Multi-reading or seasonally adjusted BP measurement methods would enhance accuracy and fairness in VBC quality assessment.
• Redesigning quality measures to incorporate seasonal adjustments is recommended, with engagement sought from NCQA and CMS for piloting.