EXPANDING THE EVIDENCE BASE IN OUTCOMES RESEARCH: USING LINKED ELECTRONIC MEDICAL RECORDS (EMR) AND CLAIMS DATA

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1 EXPANDING THE EVIDENCE BASE IN OUTCOMES RESEARCH: USING LINKED ELECTRONIC MEDICAL RECORDS (EMR) AND CLAIMS DATA A CASE STUDY EXAMINING RISK FACTORS AND COSTS OF UNCONTROLLED HYPERTENSION ISPOR 2013 WORKSHOP

2 Background Hypertension (HTN) affects 50 million people in the US and one billion people worldwide High blood pressure (BP) is the leading attributable risk factor for death worldwide The proportion of patients with HTN receiving pharmacologic therapy in the US increased from 59.4% in to 71.6% in Anti-HTN treatment is associated with significant reductions in stroke, MI, and heart failure Despite the large number of available anti-htn drugs and sizeable body of data demonstrating their efficacy, control of HTN in the US remains poor This study examines the risk factors and per patient healthcare costs associated with uncontrolled HTN Source: Yoon S, Ostchega Y, Louis T. Recent trends in the prevalence of high blood pressure and it s treatment and control, NCHS Data Brief Oct; (48):

3 Study Objectives Identify the demographic and clinical characteristics associated with uncontrolled HTN within a commercially-insured population in the US. Quantify the incremental costs associated with uncontrolled HTN within a commercially-insured population in the US. 3

4 Patient Selection Criteria Patients were required to have at least 5 BP readings during their period of health plan enrollment The first or index reading had to be between 1/1/2008 and 7/1/2009 (BP i1 ) The last reading had to be at least 6 months after the first 18 years of age on the index date 12 months of continuous health plan and pharmacy benefit enrollment prior to the index date At least one medical claim with a diagnosis of HTN (ICD-9-CM 401.xx-405.xx) at any time prior to the index date (extending to 1/1/2004) No evidence of cancer or pregnancy during the pre- or postindex periods 4

5 Analytic Cohort Definitions BP control was determined based on a weighted average of BP readings recorded during the follow-up period Each reading was weighted by the number of days elapsed until the next reading Patients assigned to BP cohorts as follows: Controlled Patients with Type II diabetes or CKD: SBP <130 mmhg and DBP <80 mmhg All other patients: SBP <140 mmhg and DBP <90 mmhg Uncontrolled Patients with Type II diabetes or CKD: SBP 130 mmhg or DBP 80 mmhg All other patients: SBP 140 mmhg or DBP 90 mmhg

6 Study Time Periods 12 - MONTH PRE - INDEX PERIOD Comorbid conditions/clinical characteristics Drug treatment patterns PATIENT SELECTION PERIOD (INDEX DATES) Demographic characteristics measured as of Index Date VARIABLE DURATION ( 6 MONTH) POST INDEX - PERIOD Drug treatment patterns Healthcare utilization Healthcare costs 1/1/2007 1/1/2008 7/1/2008 1/1/2009 7/1/2009 1/1/2010 1/1/2011 6/30/2011 6

7 Analysis of Adjusted Incremental Costs of Uncontrolled HTN Objective: to estimate the incremental cost of uncontrolled HTN relative to controlled HTN Generalized linear regression model with log link and gamma variance functions were estimated for total cost Variance function selected based on Park test and Akaike s information criterion First-order interactions were investigated and retained in the model if significant Recycled prediction simulation was used to estimate the incremental cost 95% confidence interval around adjusted annual incremental cost was determined using a bootstrapping method with 500 iterations Models fit to the data with the Genmod procedure in SAS 9.2 Total annual costs were adjusted for: age, gender, race, geographic region, type of health plan, presence of capitation, months of post-index follow-up

8 Assessment of Risk Factors Associated with HTN Objective: assess the risk factors associated with uncontrolled HTN/not reaching BP goal post-index Risk factors were identified using logistic regression models with an indicator of uncontrolled BP as the outcome and a list of postulated risk factors as the covariates Adjusted odds ratio and 95% confidence limits for uncontrolled/not at goal BP compared to controlled/at goal BP were calculated First-order interactions were investigated and retained in the model if significant. Goodness of fit was assessed with the Hosmer and Lemeshow test and the c statistic.

9 Demographic and Pre-Index Clinical Characteristics Demographic Characteristics UNCONTROLLED N=5,061 CONTROLLED N=12,750 p-value Age (Mean, SD) < Male (%, N) 2, % 5, % < Presence of Capitation (N, %) % 1, % Race (N, %) (from EMR) < White 2, % 6, % Black/African American % % Asian % % Hispanic % % Other/Unknown 2, % 5, % Days of Follow-up (Mean, SD) < Clinical Characteristics Body Mass Index (Mean, SD) (from EMR) < No. unique 3-digit ICD-9-CM diagnosis codes (Mean, SD) Antihyperlipidemic medication use (N, %) 2, % 5, % < No. unique antihypertensive medications (Mean, SD) <

10 Select Pre-Index Comorbidities by Cohort 100.0% 90.0% 80.0% 70.0% 60.0% 50.0% 40.0% 30.0% 20.0% 10.0% 0.0% Uncontrolled Controlled

11 Unadjusted Healthcare Costs by Cohort $6,000 $5,000 $4,000 $3,000 $2,000 $1,000 Uncontrolled Controlled $0

12 Adjusted Incremental Annual Healthcare Costs Adjusted* incremental cost Confidence limits Lower 95% Upper 95% BP uncontrolled vs. controlled $1,301 $536 $2,030 * Adjusted for age, gender, race, geographic region, type of health plan, presence of capitation, months of post-index follow-up

13 Select Risk Factors for Uncontrolled HTN Patient characteristic Adjusted Odds Ratio Lower Confidence Limit Upper Confidence Limit Diabetes & CKD vs. none Diabetes, no CKD vs. none CKD, no diabetes vs. none Males, ages 65+ vs. Females, ages Males, ages vs. Females, ages Males, ages vs. Females, ages Males, ages vs. Females, ages Black vs. White Hypertensive heart disease Cerebrovascular disease Other race vs. White vs. 0 anti-htn medications at Index Body Mass Index (BMI) Months of follow-up Hyperlipidemia Ischemic heart disease Cardiovascular disease Antihyperlipidemic medications Atrial fibrillation Log # ICD9s

14 Conclusions Uncontrolled BP is associated with higher costs after adjustment for patient demographic characteristics Significant risk factors for uncontrolled HTN Demographic characteristics: race, age, and sex Clinical characteristics: BMI, number of unique recorded ICD-9-CM diagnoses, diabetes, CKD, hypertensive heart disease 14

15 Key Strengths and Limitations of Claims Data for Case Study Strengths Captures all medical services during period of eligibility Objective, comprehensive information on utilization and cost Limitations Does not contain clinical detail such as BP and BMI ICD-9 coding is relatively high level Unable to ascertain whether patients diagnosed with HTN are controlled or uncontrolled 15

16 Key Strengths and Limitations Of EMR Data for Case Study Strengths Detailed vitals (BP) available, collected at the point of care Enables the examination of hypertensive patients who are controlled and uncontrolled Longitudinal view based on repeated clinical assessments Enables the construction of indicators incorporating multiple assessments over time Enables the evaluation of a potential change in status over time (i.e., reaching BP goal ) Limitations Does not contain data from the inpatient setting Cost and reimbursement data are not captured 16