Visual analytics for epidemiologists: understanding the interactions between age, time, and disease with multi-panel graphs

Abstract

Background: Visual analytics, a technique aiding data analysis and decision making, is a novel tool that allows for a better understanding of the context of complex systems. Public health professionals can greatly benefit from this technique since context is integral in disease monitoring and biosurveillance. We propose a graphical tool that can reveal the distribution of an outcome by time and age simultaneously.

Methodology/principal findings: We introduce and demonstrate multi-panel (MP) graphs applied in four different settings: U.S. national influenza-associated and salmonellosis-associated hospitalizations among the older adult population (≥65 years old), 1991-2004; confirmed salmonellosis cases reported to the Massachusetts Department of Public Health for the general population, 2004-2005; and asthma-associated hospital visits for children aged 0-18 at Milwaukee Children's Hospital of Wisconsin, 1997-2006. We illustrate trends and anomalies that otherwise would be obscured by traditional visualization techniques such as case pyramids and time-series plots.

Conclusion/significance: MP graphs can weave together two vital dynamics--temporality and demographics--that play important roles in the distribution and spread of diseases, making these graphs a powerful tool for public health and disease biosurveillance efforts.

Figure 1. Typical patterns observed in image plots used to study the association between age, time, and the disease of interest.

Figure 2. Multi-panel graph of influenza in the United States older adult population (aged 65 and over) 1991–2004.

Lower left: outcome pyramid; upper right: time-series plot; lower right: image plot.

Figure 3. Multi-panel graph of salmonellosis in the United States older adult population (aged 65 and over) 1991–2004.

Lower left: outcome pyramid; upper right: time-series plot; lower right: image plot.

Figure 4. Multi-panel graph of salmonellosis in the general Massachusetts population 2004–2005.

Lower left: outcome pyramid; upper right: time-series plot; lower right: image plot.

Figure 5. Multi-panel graph of asthma in children aged 0–18 in Milwaukee 1997–2006.

Lower left: outcome pyramid; upper right: time-series plot; lower right: image plot.