Date on Master's Thesis/Doctoral Dissertation

5-2014

Document Type

Doctoral Dissertation

Degree Name

Ph. D.

Department

Epidemiology and Population Health

Committee Chair

Groves, Frank Dunbar

Committee Co-Chair (if applicable)

Folz, Rodney J.

Committee Member

Folz, Rodney J.

Committee Member

Baumgartner, Richard N.

Committee Member

Muldoon, Susan

Committee Member

Brock, Guy

Subject

Lungs--Diseases, Obstructive--Treatment; Health facilities

Abstract

Background: Chronic obstructive pulmonary disease (COPD) is a progressive disease of the respiratory system characterized by airflow limitation that is not completely reversible and is associated with systemic effects especially of the cardiovascular system. COPD is frequently complicated by acute exacerbations that contribute to physical impairment and increased health care use. As COPD is a chronic lung disease with significant systemic manifestations, it is important to have chronic disease management programs specifically targeting individuals with COPD designed to improve their overall quality of life, reduce the burden of disease and decrease the impact of COPD on daily life. Chronic disease management encompasses a multidisciplinary approach designed to enhance the quality and cost-effectiveness of health care for chronic conditions and has been defined as “an approach to patient care that emphasizes coordinated, comprehensive care along the continuum of disease and across health care delivery systems”. The purpose of this present study is to evaluate the effectiveness of a chronic obstructive pulmonary disease management program implemented at the University of Louisville in 2011. Methods: We conducted a retrospective observational cohort study of COPD subjects using clinical data from medical records and cost data from a claims dataset. Respiratory health was assessed by pulmonary function testing, St. George Respiratory questionnaire, COPD Assessment Test (CAT), 6 minute walk test (6MWT), Modified Medical Research Council (mMRC) dyspnea scale, and BODE index. General measures include Duke Profile for assessing overall health and Patient Health Questionnaire (PHQ-9) for assessing depression. At baseline, chi-square test for categorical variable and t-test for continuous variable was used to check for any difference between the two groups. To check for any longitudinal significant change in quality of life measures like SGRQ, CAT score, mMRC scale, BODE index, six minute walk distance and PFT measures from baseline paired t-test was performed. For each subject, the baseline probability of participation in the disease management program was calculated by the propensity score method using logistic regression analysis. Multiple linear regression analysis was performed to assess the rate of deterioration of various clinical parameters like FEV1 and FVC between two groups. Cost analysis was done by comparing the cost related to COPD among subjects in DMP group versus those under usual care. These costs includes total COPD cost, and also sub-categories of cost like office visit cost, in-patient hospitalization (IPH) cost, out-patient hospitalization (OPH) cost, pharmacy cost, cost related to home care and laboratory cost. Results: A total of 52 subjects were enrolled in the disease management program between February 1st 2011 and December 31st 2013: 37 in 2011, 11 in 2012 and 4 in 2013. The usual care group consists of 662 subjects diagnosed with COPD. There is a significant difference in average age of subjects between the two groups (54.2 in DMP versus 58.3 in usual care; P value 0.0094). Subjects who suffered from asthma, rhinitis and arthritis were significantly more likely to enroll in the disease management program. At baseline, the average PHQ9 was 6.3 which improved at the end of 12 months (mean = 4) and at 24 months (mean = 3.1). At baseline, the average duke score was 64.1 which were improved at the end of 12 months (mean = 71.6) and 24 months (mean = 68.3). At baseline average SGRQ score was 37.1 which were improved at the end of 12 months (mean = 28.4, P = 0.02) and 24 months from (mean = 30.2, P = 0.21). We found that not only did those subjects enrolled in the COPD program decrease their rate of loss of lung function, but remarkably showed a significant improvement in FEV1 from baseline to 12 months (mean difference: 140 ml, P value = 0.0046) and from baseline to 24 months (mean difference: 30 ml, P value 0.55). Average cost per person per year among subjects in DMP group in first year is $3693, which decreased to $3608.8 in second year and to $2934 in third year. Pharmacy cost contributes majority of total COPD cost followed by office cost and out-patient hospitalization. There is a significant decline in cost related to all major diseases like arthritis, hypertension, hyperlipidemia, diabetes, and osteoporosis after enrollment of COPD subjects into disease management program comparing to cost before enrollment into program. Average cost per person per year for in-patient hospitalization is significantly high for subjects in usual care ($5578.7) versus subjects in DMP group ($250.9). Conclusion: The University of Louisville COPD disease management program appears to be effective in improving lung health and reducing airflow limitations among COPD subjects as evidence by significant improvement in objective measures like FEV1. Program is also effective in reducing the impact of COPD on daily activities as evident by significant improvement in subjective measures for health related quality of life like St George Respiratory Questionnaire, COPD assessment test, PHQ9 and Duke Profile. Notwithstanding subjects in DMP had higher COPD related cost, they had significantly low in-patient hospitalization cost and also significant reduction in cost associated with major co-morbidities after enrollment in the disease management program.

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