Rini Vohra

Date of Graduation

2016

Document Type

Dissertation

Degree Type

PhD

College

School of Pharmacy

Department

Pharmaceutical Sciences

Committee Chair

Suresh Madhavan

Committee Co-Chair

Nilanjana Dwibedi

Committee Member

Susannah Poe

Committee Member

Usha Sambamoorthi

Committee Member

Claire StPeter

Abstract

Study 1.;Background: Individuals with autism spectrum disorders (ASD) have extensive comorbidities. The current literature lacks documentation of prevalence of different types of comorbidities and their association with healthcare utilization and expenditures among adults with ASD as compared to adults without ASD.;Aim: To determine: 1) the differences in prevalence of psychiatric, non-psychiatric comorbidities, other health conditions, healthcare utilization, and expenditures among adults with and without ASD; and 2) the association of type of comorbidity with healthcare utilization and expenditures of adults with ASD.;Method: A retrospective cohort study using claims data from three state Medicaid Analytic eXtract was conducted. Adults aged 22--64 years with ASD (ICD9-CM code: 299.xx) with at least one inpatient or two outpatient claims on separate service dates who were continuously enrolled between January 1, 2000 to December 31, 2008 were identified. ASD cases were matched to no ASD controls by age, sex, and race using propensity score matching (1:3). Baseline and outcome differences across cases and controls were examined using bivariate analyses for categorical (chi-square) and continuous independent variables (t-tests). All cause health care utilization (outpatient visits, inpatient hospitalizations, emergency room, and prescription drug use), and associated health care costs were assessed during the follow-up year. Multivariate multinomial logistic regressions for healthcare utilization and generalized linear models with gamma distribution for expenditures were conducted to compare healthcare utilization and expenditures among adults with and without ASD. Association of type of comorbidity with healthcare utilization (binary and multinomial logistic regressions) and expenditures (generalized linear models with gamma distribution) were also analyzed among adults with ASD. Multivariate regression analyses were adjusted for state, identification year, patient socio-demographics, baseline prescription drug use, and county characteristics.;Study 2.;Background: The use of emergency department (ED) visits among adults with psychiatric needs is known to be high, yet there are no comprehensive studies that have characterized ED use among adults with ASD. Adults with ASD may be at substantial risk of high ED use and costs.;Objectives: 1) To examine the trends in ED visits and mean total ED charges for adults with ASD over a period of 6 years; 2) To examine and compare the types of ED use (psychiatric, non-psychiatric, and injury) among adults with and without ASD.;Methods: A cross-sectional study using discharge level data from the Nationwide Emergency Department Sample (NEDS; 2006--2011) was conducted to the examine trends and characteristics of ED visits among adults aged 22--64 years, with and without ASD (ICD9-CM code: 299.xx). ASD cases were matched to no ASD controls by age and gender using propensity score matching (1:3). Trends are presented as annual weighted rates and mean total charges for all, psychiatric (principal diagnosis of a psychiatric disorder), non-psychiatric (principal diagnosis of a non-psychiatric disorder), and injury (any) visits among adults with ASD. Chi square analyses and t-tests were conducted to examine sub group differences in socio-demographic, hospital, and patient disposition characteristics across adults with and without ASD. Weighted rates of psychiatric, non-psychiatric, and injury visits were compared between adults with and without ASD. Multivariate adjusted logistic regressions were run to examine the likelihood of a psychiatric, non-psychiatric, and an injury visit among adults with ASD as compared to adults without ASD. All analyses adjusted for the NEDS complex survey design.;Study 3.;Background: Lack of gold standard ASD treatment, approved guidelines, and strong evidence based treatments lead to greater off label prescribing with no information on the long term effects of high prescription drug use among individuals with ASD. Extent of general and psychotropic polypharmacy among adults with ASD has not been studied till date.;Aim: 1) To examine and compare the types of prescription drug use and rates of general and psychotropic polypharmacy among adults with and without ASD; 2) To examine predictors of polypharmacy among adults with ASD.;Method: A retrospective cross sectional study using claims data from three state Medicaid Analytic eXtract was conducted. Adults aged 22--64 years with ASD (ICD9-CM code: 299.xx) who were continuously enrolled between January 1, 2000 to December 31, 2008 were identified. ASD cases were 1:3 matched to no ASD controls by age, sex, and race using propensity score matching. Rates of different prescription drug classes, general polypharmacy, and psychotropic polypharmacy among adults with and without ASD were compared using chi-square tests. T-tests were conducted to examine the differences in mean annual number of claims for specific drug classes between adults with and without ASD. Multivariate multinomial logistic regressions were run to examine the likelihood of general and psychotropic drug polypharmacy among adults with ASD as compared to adults without ASD, after adjusting for identification year, patient socio-demographics, county characteristics, and number of comorbidities. (Abstract shortened by UMI.).

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