Pain Medication Utilization Among Cancer Survivors: Findings from Medical Expenditure Panel Survey
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Pain Medication Utilization Among Cancer Survivors: Findings From Medical Expenditure Panel Survey A dissertation submitted to the University of Cincinnati Graduate School in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in the Department of Health Outcomes of James L. Winkle College of Pharmacy by Amarsinh Desai, Bachelors of Pharmacy, Rajiv Gandhi University of Health Sciences, Karnataka, India, 2007 Masters of Science, Long Island University, New York, US, 2010 Committee Members Pamela C. Heaton, PhD, Chair Christina M.L. Kelton, PhD Jill M. Boone, Pharm D Teresa M. Cavanaugh, Pharm D, MS, BCPS Alex C. Lin, PhD ABSTRACT Background: Cancer pain, either tumor-related or treatment-related, is common among cancer survivors. The objectives of this study were to 1) report recent trends in the pharmaceutical treatment of pain and HRQoL among cancer survivors; 2) to understand better the reasons for and the effects of pharmaceutical treatment of pain and 3) to assess relationship between pain medication use and workers’ productivity. Methods: This was a retrospective observational study using a nationally representative survey database. Cancer survivors, excluding survivors of non-melanoma skin cancer, were identified using survey questions and clinical classification codes. Utilization, cost and payer cost shares were obtained for following class of drugs such as non-opioids, opioids, narcotic analgesic combinations and adjuvants annually from 2008 to 2013. The demographic, geographical, clinical and economic predictor variables were regressed to assess their association with the total number of pain/opioid prescriptions. Productivity measures obtained from SF-12 and CSAQ were assessed for their association with pain/opioid medications use. Descriptive statistics were computed employing appropriate statistical procedures for the MEPS with its unique sampling design. Estimates were reported using zero-inflated Poisson regression. Results: Out of 23.4 million cancer survivors in 2008, 40.8% took pain medications; in 2013, 43.9% of 24.8 million survivors took pain medications; these percentages exceed those for patients without a history of cancer. The total number of prescriptions for pain medications increased from 60.3 million in 2008 to 74.3 million in 2013. The utilization of opioids and adjuvant analgesics was significantly (p<0.05) higher among the cancer survivors compared to individuals without cancer history. The cost (not adjusted for inflation) of pain medications increased from $3.5 billion in 2008 to $5.6 billion in 2013. Overall, the patient cost share decreased from 23.3% in 2008 to 17.0% in 2013. Stratified by opioid exposure the worst PCS and MCS scores were reported by opioid users. The odds of not receiving opioid medications was significantly (p<0.05) higher among elderly [age 65-74, OR= 2.73 (1.32 - 5.64)], i minorities belonging to other race group [OR= 2.14 (1.03 - 4.43)], adjustment disorder [OR=3.41 (1.35 - 8.57)], more than one mental condition [OR=3.64 (1.51 - 8.76)]; from the count model significant (p<0.05) association was obtained for variables, experiencing high/severe pain [3.49 (2.09 - 5.84)], arthritis [1.93 (1.33 - 2.80)], more than one painful comorbidities [1.69 (1.12 - 2.55)], higher income [1.52 (1.09 - 2.11)], insurance status change over time [2.12 (1.41 - 3.16)]. Nearly, 54.0%-62.0% experienced little/no work limitation reported through SF-12 productivity measures. Among those who experienced no work limitation, significantly (p<0.05) higher proportion (73.0%) of respondents were non-users of pain medications. A higher proportion (75.0%) of post-treatment cancer survivors feels productive at work. Conclusion: This study reported substantial changes in treatment of cancer pain over-time. The economic impact of cancer survivorship is increasing with growing cancer population. The spending in terms of patient share decreased. Poor HRQoL scores were obtained stratified by opioid exposure. Many post- treatment cancer survivors were employed and remained productive. ii iii ACKNOWLEDGEMENTS This dissertation becomes a reality because of kind support and immense help of many significant individuals in my life. I would like to convey deepest heartfelt thanks to all of them. Foremost, I’m lifetime indebted to my mentors Dr. Pamela C. Heaton and Dr. Christina M.L Kelton. Thank you for always being there at personal and professional fronts! I’m thankful to Dr. Pamela C. Heaton for her mentorship, help and support during doctoral program. PhD education and training was challenging for me and she made sure I acquire the research skills. I would like to thank Dr. Heaton for her time and critical suggestions towards publications, presenting research posters at national and international conferences, attending workshops and with dissertation. The graduate and research assistantship helped me gain valuable experience and facilitated building strong professional profile. Dr. Heaton’s leadership and research-oriented observation skills have always inspired me. Thank you for giving me opportunity to pursue PhD under your mentorship that significantly helped to shape my future! My PhD is incomplete without Dr. Christina M.L. Kelton’s help and endless guidance. Her contributions towards my growth as PhD student are significant. I look up to her for thinking differently, scientific writing and research skills. I’m grateful for her guidance towards research projects, publications and dissertation. I was truly benefited and inspired with her research skills and outstanding experience. I greatly appreciate my doctoral committee Dr. Jill M. Boone, Dr. Teresa M. Cavanaugh and Dr. Alex C. Lin, for their scholarly advice and critical suggestions. I am very grateful for their valuable inputs, clinical expertise and willingness to serve on my committee. I also would like to thank Dr. Jonathan Penm and Dr. Jane Pruemer for their great help, assistance with dissertation. iv My thanks also extend to peers, faculty and staff at University of Cincinnati, college of pharmacy and Allied Health Faculty of Graduate Studies. I would like to extend my gratitude towards my family for their help, support and encouragement in chasing my dreams. Many thanks to my beloved and supportive wife, Vibha Desai who is always by my side during the times when I needed her the most. To my beloved son, Aryaveer Desai: I never understood life more meaningfully until you were born and stepped in our world during PhD studies. You became part of my dissertation journey as well. Every year celebrating your birthday is the strongest motivation towards the completion of PhD. I look forward sharing the stories when you grow big. v Table of Contents LIST OF TABLES ................................................................................................................... ix LIST OF FIGURES ................................................................................................................. xi LIST OF GLOSSARY AND ACRONYMS........................................................................... xii CHAPTER ONE:- INTRODUCTION ..................................................................................... 1 1.1 Overview .................................................................................................................... 1 1.2 Literature Review....................................................................................................... 2 1.2.1 Types of Cancer Pain ...................................................................................... 4 1.2.2 Causes of Cancer Pain .................................................................................... 7 1.2.3 Epidemiology of Cancer Pain ....................................................................... 10 1.2.3.1 Epidemiology by Type of Cancer Pain ........................................................ 11 1.2.3.2 Epidemiology of Cancer Pain by Cancer Site .............................................. 17 1.2.3.3 Epidemiology of Cancer Pain by Cancer Staging ........................................ 21 1.3 Cancer Pain Management ........................................................................................ 23 1.4 Barriers to Cancer Pain Management ...................................................................... 28 1.5 Gaps in Current Knowledge ..................................................................................... 30 1.6 Significance.............................................................................................................. 32 1.7 Objectives ................................................................................................................ 33 CHAPTER TWO:- METHODOLOGY .................................................................................. 35 2.1 Data Overview ............................................................................................................ 35 2.2 MEPS Sample Design ................................................................................................. 37 2.3 IRB Approval Statement ............................................................................................. 38 2.4 Methodology: Objective 1 ....................................................................................... 39 2.4.1 Data Source & Study Design ........................................................................ 39 2.4.2 Study Population: Cancer Survivors ...........................................................