OBJECTIVES: In recent years, methodologies used in outcomes research have advanced. In a field where many researchers from a variety of disciplines (e.g., clinicians, epidemiologists, economists, statisticians) interact frequently, a tool to communicate information clearly and effectively through graphical means has become necessary. We present treatment patterns among Veterans Health Administration (VHA) patients diagnosed with ankylosing spondylitis (AS) using data visualization techniques. METHODS: Using the VHA Medical SAS® Dataset, we selected patients ≥18 with at least one AS diagnosis. We identified patients who initiated therapy with tumor necrosis factor (TNF) and non-TNF agents. For 2 years after the initiation date, we analyzed switches to another TNF, a non-TNF, and continuation and discontinuation treatment patterns. Using a processing language, we created a data visualization tool to demonstrate changes in treatment patterns after the first and second switches. RESULTS: A total of 1,021 AS patients initiated therapy with TNF. 13.52% of these patients switched to another TNF, 0.20% switched to a non-TNF, 49.56% discontinued therapy and 36.73% continued their initial therapy. Among patients who switched to another TNF, 60.87% remained on the switched therapy, while 31.16% discontinued therapy, 7.97% switched to another TNF, and no patients switched to a non-TNF. 81.82% of patients who made a second switch to a TNF medication remained on it, while 9.09% discontinued. A total of 84 AS patients initiated therapy with a non-TNF. 4.76% of these patients switched to a TNF, 1.19% switched to another non-TNF, 93.61% discontinued therapy and no patients continued. Of those patients whose first switch was to a TNF, 50% continued while the remaining 50% discontinued. No second switches were made. CONCLUSIONS: Treatment patterns can be difficult to present, especially when analyzing several years of data and various drug switches. Data visualization tools can help present these complicated flows effectively to researchers.