Abstract
Symptomatic chronic diseases differ in their propensity for serious costly morbidity. Reliable and predictable deterioration presentations can be associated with very narrow margins between symptoms and the onset of serious complications. The inflammatory bowel diseases (IBD): Crohn’s Disease and Ulcerative Colitis are examples of this. As a result, they have high cost per capita with significant variation in that cost. Reliable metrics for assessing the relative volatility of chronic diseases are lacking.
In finance, the volatility of a stock is measured using the beta coefficient, a measure of the relative volatility of an individual stock in relation to the that of an index.[i] By definition, the specific index has a beta of 1.0, and individual stocks are ranked according to how much they deviate from the market based on their beta coefficient. A stock that demonstrates more volatility than the market over time has a beta above 1.0.
We postulated that chronic gastrointestinal diseases can be profiled using a similar measurement of volatility based on cost. Using a data set of 40,523 members obtained from Health Care Service Corporation, which included professional, facility and pharmacy claims for calendar year 2017, we calculated an index and beta rating for the major gastrointestinal disorders: gastroesophageal reflux disease (GERD), Peptic Ulcer disease (PUD), Gastritis, Celiac disease, Pancreatitis, Irritable Bowel Syndrome (IBS), Crohn’s disease (CD), Ulcerative colitis (UC), Colon Polyps and Diverticulitis:
Method: The Total Disease Specific Cost (TDSC) was calculated from claims data for each condition using ICD - Codes.A GI Disease index (GIDI) was created by calculating the TDSC of all of the above conditions. The GIDI TDSC was then segregated into deciles.The cost/decile was then analyzed for each condition and compared against the GI IndexA beta rating (Beta) was calculated using Standard Deviations of the relative cost/decile (SDCD) as follows: Beta = SDCD (Illness)/SDCD (Index)
Results: Using this methodology, the GI Index and individual beta ratings are numerically and graphically shown in the figures. Whereas CD and UC have strongly positive Beta scores, the remainder of the GI illnesses do not as compared to the GI Index.
Figure 1. Major Gastrointestinal illnesses’ Beta Rating with respect to GI Index
Table 1. Summary of major Gastrointestinal illnesses’ cost by decile and Beta Rating
Conclusions: Gastrointestinal disorders can be categorized, based on their volatility, into a beta rating[ii]. Disorders associated with high cost and high variability in cost have a high-beta rating compared to the GI disorder index. This is a critical finding as high-beta conditions are those toward which management payments should be focused as they benefit most from patient engagement, care coordination and care managment programs to improve outcomes and control costs. [i] Sharpe W. Portfolio theory and capital markets. New York: McGraw Hill, 1970.[ii] Kosinski L, Brill J; Clinical Gastroenterology and Hepatology Vol. 14, No. 12, P1751-1752
Gastrointestinal Diseases in Primary Immunodeficiencies