Using zero-inflated models to understand how chronic conditions and chronic pain impact CAM utilization

Previous CAM research has theorized that individuals are pushed into using CAM because conventional Western medicine often cannot cure or is ineffective in treating their chronic illness or chronic pain. Although researcher have noted a strong and consistent relationship between chronic illness, pain and utilization of CAM, what is still unknown is how chronic illness and pain influence both the decision to try CAM and how much CAM is used. Using the 2002 National Health Interview Survey's Supplemental Section, zero-inflated Poisson and zero-inflated negative binomial models were employed to examine how chronic conditions and chronic pain impact CAM utilization across five domains. Results indicate that level of pain is the only consistent predictor of both the odds of using CAM as well as the number of CAM types used. Findings, however, were mixed for health status and chronic conditions. These findings support previous research that chronic pain is associated with higher use of CAM; however, by expanding CAM utilization research to zero-inflated models, our research provides distinction between those individuals who used a CAM therapy once and someone who used five CAM therapies. This distinction is important in understanding what the factors are that push an individual into initially trying CAM versus factors that impact why an individual continues to use CAM. It not only broadens the overall knowledge of CAM utilization, but can begin to inform those interested in health disparities in Western medicine utilization and to inform those interested in integrative health care.