Pylypchuk R, et al. - Researchers compared of the performance of two cardiovascular disease risk prediction equations: one newly-developed equation based on a nationally representative cohort of patients in contemporary primary care in New Zealand vs older 2013 American College of Cardiology/American Heart Association Pooled Cohort Equations (PCEs) currently recommended in the US. Most subjects seemed to be at low risk of cardiovascular disease, which clarifies why the PCEs, based mainly on old cohorts, significantly overestimated risk. Though the PCEs and many other equations warranted recalibration to mitigate overtreatment of the healthy majority, new predictors were required that included measures of socioeconomic deprivation and multiple ethnicities for the detection of vulnerable high-risk subpopulations that could otherwise be undertreated.

Methods

• The PREDICT study enrolls subjects in routine primary care when general practitioners in New Zealand use PREDICT software for determining their patients' risk profiles for cardiovascular disease, which are prospectively linked to national ICD-coded hospitalization and mortality databases.
• Male and female patients in primary care who had no prior cardiovascular disease, renal disease, or congestive heart failure were used for the study population.
• Using Cox regression models which included clinical predictors, an area-based deprivation index, and self-identified ethnicity, new equations forecasting total cardiovascular disease risk were developed.
• The equations were evaluated for calibration and discrimination performance and compared with PCEs.
• The additional predictors included in the new PREDICT equations were also added to the PCEs see if they were independent predictors in the US equations.

Results

• For this study, outcome events were calculated for 401,752 people aged 30-74 years at the time of their first PREDICT risk assessment between Aug 27, 2002, and Oct 12, 2015, which was about 90% of the eligible cohort.
• Mean follow-up was 4.2 years and a third of the participants were followed for 5 years or more.
• As per the data, 15,386 (4%) people had cardiovascular disease events during 1,685,521 person-years follow-up. Of these, 1,507 (10%) were fatal, and 8,549 (56%) met the PCEs definition of hard atherosclerotic cardiovascular disease.
• The median 5-year risk of total cardiovascular disease events predicted by the new equations was 2.3% in women and 3.2% in men.
• A rise was noted in the multivariable adjusted risk by approximately 10% per quintile of socioeconomic deprivation.
• Findings illustrated that Maori, Pacific, and Indian patients appeared to be at 13-48% higher risk of cardiovascular disease vs Europeans, and Chinese or other Asians were at 25-33% lower risk of cardiovascular disease than Europeans.
• Furthermore, PCEs overestimated hard atherosclerotic cardiovascular disease by about 40% in men and by 60% in women.
• The additional predictors in the new equations served as independent predictors in the PCEs.
• With regard to all performance metrics, new equations were found to be notably better compared to PCEs.