The PRESERVE dataset is comprised of patients diagnosed with Heart Failure (HF) and known left ventricular systolic function between January 1, 2005 and December 31, 2008. Preserved left ventricular (LV) function is typically defined as having a LV ejection fraction of ≥50% or a qualitative assessment of normal or preserved systolic function. Each participating site followed the same data collection steps and transferred their data to Kaiser Permanente Northern California (KPNC), where it is compiled to produce an analytic dataset with a single, common structure. The compiled dataset is hosted at KPNC and may be analyzed as a whole or broken down by site if desired.
30,094 total patients were identified, aged 21 years or older at the time of Heart Failure diagnosis.
Table 1. PRESERVE Dataset Member Counts by Site
Number of Members||
Percent of Dataset|
|Kaiser Permanente Northern California||21,565||71.7%|
|Kaiser Permanente Colorado||3,329||11.1%|
|Kaiser Permanente Northwest||3,591||11.9%|
|Meyers Primary Care Institute Of Fallon Health Plan||1,609||5.3%|
The mean age was 73.7 years old. 46% of the cohort was female. 75.3% of the cohort were white, 8% black, 6% Asian/pacific island, and 10.8% had an unknown or missing race assignment.
Figure 1. Distribution of Age and Gender for Patients in the PRESERVE Study
Figure 2. Distribution of Race for Patients in the PRESERVE Study
All member data was extracted using the Virtual Data Warehouse (VDW). The VDW is a standardized resource comprised of: (1) computerized datasets stored behind separate security firewalls, including variables with identical names, formats, and specifications; (2) informatics tools that facilitate storage, retrieval, processing, and managing the datasets; and (3) detailed data documentation. All data are linked by a unique identifier so that data elements can be rolled up to the individual person-level. Quantitative and qualitative left ventricular ejection fraction assessments were collected both manually and via electronic medical records. Qualitative assessments were considered over quantitative. Qualitative assessments were standardized and placed in three categories (normal, mild, and reduced) at the host site (KPNC). The VDW was used to characterize each sites cohort of patients with regard to relevant exposure and outcome variables.
Gurwitz JH, Magid DJ, Smith DH, Goldberg RJ, McManus DD, Allen LA, Saczynski JS, Thorp ML, Hsu G, Sung SH, Go AS. Contemporary Prevalence and correlates of incident heart failure with preserved ejection fraction. The American Journal of Medicine 2013; 5: 393-400.
McManus DD, Hsu G, Sung SH, Saczynski JS, Smith DH, Magid DJ, Gurwitz JH, Goldberg RJ, Go AS. Atrial fibrillation and outcomes in heart failure with preserved versus reduced left ventricular ejection fraction. Journal of the American Heart Association 2013;1
Saczynski JS, Go AS, Magid DJ, Smith DH, McManus DD, Allen L, Agarek J, Goldberg RJ, Gurwitz JH. Patterns of comorbidity in older patient with heart failure: The Cardiovascular Research Network PRESERVE Study. Journal of the American Geriatrics Society;1: 26-33.