1. Disease Burden and Intensity of Antidiabetic Drug Use by Medicare Beneficiaries with Diabetes: Will Part D Make a Difference? AcademyHealth June 25, 2006 Bruce Stuart, Thomas Shaffer, Linda Simoni- Wastila, Ilene Zuckerman The Peter Lamy Center on Drug Therapy and Aging University of Maryland Baltimore

2. Page 2 The Peter Lamy Center on Drug Therapy and Aging Outline Sponsor acknowledgment: funding provided by The Commonwealth Fund under grant Benchmarking the Quality of Medication Use by Medicare Beneficiaries Background: the growing controversy over the importance of glycemic control for frail diabetics Study objectives and hypotheses Data and study sample Measures Statistical strategy Results Discussion and study implications for policy

3. Page 3 The Peter Lamy Center on Drug Therapy and Aging The Importance of Glycemic Control among Frail Older Persons Traditional diabetes guidelines Glycemic control is the mainstay of traditional guidelines for treatment of diabetes promulgated by the ADA, AHRQ, NCQA, AMDA, and other organizations. Most guidelines recognize the importance of comorbidity and frailty in making clinical treatment decisions, but offer no quantitative guidance New thinking Current approaches to assessing quality of diabetes treatment do not account for heterogeneity among older patients Less intense targets for glycemic control are warranted for older diabetics in poor health and low life expectancy

4. Page 4 The Peter Lamy Center on Drug Therapy and Aging Study Objectives and Hypotheses Objectives Benchmark prevalence and level of use of antidiabetic agents (oral hypoglycemic agents and insulins) among community-dwelling Medicare beneficiaries with diabetes stratified by burden of illness Identify factors associated with differences in antidiabetic use by burden of illness Hypotheses Factors hypothesized to be associated with higher antidiabetic drug use - Income, prescription drug coverage, severity of diabetes, obesity, health system contacts (surveillance hypothesis) Factors hypothesized to be associated with lower antidiabetic drug use - Increasing disease burden, kidney disease, hospitalization, health system contacts (competing demands hypothesis)

5. Page 5 The Peter Lamy Center on Drug Therapy and Aging Data and Study Sample Data 2002 MCBS Cost and Use files (N=12,697) Study Sample Inclusion criteria: - Self report of diabetes and/or ICD-9 diagnosis codes: 250.xx, 357.2, 362.01, 362.02, 366.41. Two or more Dx of diabetes on outpatient and carrier claims or one diagnosis on an impatient claim Exclusion criteria - In MCBS facility sample all or part year, Part A and/or B part year, any Medicare HMO enrollment, incomplete surveys Final study sample: N=1,956

6. Page 6 The Peter Lamy Center on Drug Therapy and Aging Measures Overall Burden of Illness Stratify study sample into 10 equal sized groups (deciles) by cumulative spending for all medical services including drugs Dependent Variables Any antidiabetic drug use in 2002 by type (orals, insulin), number of prescription fills per year, total pill count for oral hypoglycemics Explanatory Variables 6 domains: (1) decile assignment, (2) demographics (age, sex, race, census region), (3) economic variables (income, prescription coverage), (4) health (self-reported, ADLs, BMI, self-reported DM/no claims, diabetes complication, chronic kidney disease) (5) contacts with health system (inpatient hospital, SNF, HHA, hospice, count of physician E&M visits, count of different physicians seen in office visits), (6) denominator days

7. Page 7 The Peter Lamy Center on Drug Therapy and Aging Statistical Strategy Descriptive Charts Prevalence rates for common comorbidities by decile of medical spending Prevalence and level of antidiabetic drug use by decile of medical spending Regression Analysis Stepwise logistic and OLS regressions with explanatory variables entered in blocks representing the 6 domains of explanatory variables. Objective is to determine whether differences in drug use observed in the unadjusted stratification by decile lose significance with additional covariates, and if so which are responsible Digging Deeper Within-decile regression analysis

8. Page 8 The Peter Lamy Center on Drug Therapy and Aging Descriptive Results

9. Page 9 The Peter Lamy Center on Drug Therapy and Aging Characteristics of the Study Population (N=1,956) CharacteristicFrequency or count (SE) Demographics Age (%) Under 65 65 – 69 70 – 74 75 – 79 80+ 14.8 17.1 24.7 20.8 22.6 Female sex (%)54.8 Nonwhite (%)20.7 Geographic residence (%) East Midwest South West 18.5 25.6 43.3 12.6

10. Page 10 The Peter Lamy Center on Drug Therapy and Aging Characteristics of the Study Population (N=1,956) Economic variables Annual income (%) < $10,000 $10,000 – 20,000 $20,001 – 30,000 >$30,000 25.1 31.4 21.5 22.0 Supplementary medical insurance No coverage (%) Full year (%) Part year (%) Covered months (count) 8.5 88.0 3.5 6.4 (0.5) Prescription drug coverage No coverage (%) Full year (%) Part year (%) Covered months (count) 25.0 65.1 9.9 6.0 (0.2)

11. Page 11 The Peter Lamy Center on Drug Therapy and Aging Characteristics of the Study Population (N=1,956) Health status and disease severity factors Self-reported health (%) Poor Fair Good to excellent 13.0 28.7 57.6 3 or more activity limitations (ADLs) (%)5.5 BMI >= 30 (%)39.1 Self reported diabetes/no claim diagnosis (%)10.5 Diabetes complication (ICD-9 250.1 – 250.9) (%) 52.5 Chronic kidney disease (ICD-9 ) (%)7.1 Died (%)4.6 Denominator days* (count)353.3

12. Page 12 The Peter Lamy Center on Drug Therapy and Aging Characteristics of the Study Population (N=1,956) Health system contact variables Any hospital admission (%)27.8 Any SNF stay (%)4.3 Any home health visit (%)11.4 Any hospice stay (%)1.2 Number of office visits for evaluation and management (E&M) (count) 9.1 Number of different physicians seen for E&M visits (count) 4.8

13. Page 13 The Peter Lamy Center on Drug Therapy and Aging Figure 1. Prevalence of Selected Diseases among Medicare Beneficiaries with Diabetes Stratified by Decile of Annual Medical Spending, 2002

14. Page 14 The Peter Lamy Center on Drug Therapy and Aging Disease Burden and Medication Use: the Inverted U

15. Page 15 The Peter Lamy Center on Drug Therapy and Aging Figure 2. Unadjusted Annual Prevalence of Antidiabetic Medication Use by Decile of Annual Medical Spending

16. Page 16 The Peter Lamy Center on Drug Therapy and Aging Figure 3. Unadjusted Mean Annual Prescription Fills for Oral Antidiabetic Medications by Users of These Drugs

17. Page 17 The Peter Lamy Center on Drug Therapy and Aging Figure 4. Unadjusted Mean Annual Pill Counts for Oral Antidiabetic Medications Stratified by Users of These Drugs

18. Page 18 The Peter Lamy Center on Drug Therapy and Aging Multivariate Results

19. Page 19 The Peter Lamy Center on Drug Therapy and Aging Adjusted Odds Ratios for Any Use of Antidiabetic Medications by Study Subjects DecileDecile Only Regression Unadj. Odds (95% CI) Full Model Adj. Odds (95% CI) 1 2 3 4 5 6 7 (reference) 8 9 10 0.40 (0.26-0.60)** 0.61 (0.40-0.91)* 0.79 (0.52-1.20) 0.82 (0.54-1.24) 0.64 (0.42-0.97)* 0.87 (0.57-1.33) 1.00 0.81 (0.53-1.23) 0.83 (0.55-1.27) 0.53 (0.36-0.81)** 0.56 (0.34-0.91)* 0.71 (0.45-1.13) 0.81 (0.51-1.28) 0.87 (0.56-1.37) 0.66 (0.42-1.03) 0.80 (0.51-1.24) 1.00 0.79 (0.50-1.25) 0.83 (0.52-1.35) 0.69 (0.41-1.16) *p <.05 **p <.01

20. Page 20 The Peter Lamy Center on Drug Therapy and Aging Factors Affecting Treatment Odds (or not) None of the demographic or economic factors was a consistent predictor of likelihood of using antidiabetic medicine. Prescription coverage plays no significant role. Significant (p =30 (1.51 to 1.53), self reported diabetes/no claim (0.20), diabetes complications (1.75 to 1.80), chronic kidney disease (0.55) Only one significant (p <.05) health system contact variables (odds ratios in model 6): number of different physician seen in office visits (0.95) The adjusted treatment odds in the full model are 16 points higher in each tail of the distribution, but the inverted U pattern remains

21. Page 21 The Peter Lamy Center on Drug Therapy and Aging Adjusted Coefficients for Annual Prescription Fills for Study Subjects Using Oral Antidiabetic Medications DecileDecile Only Regression Unadj. Coef. (95% CI) Full Model Adj. Coef. (95% CI) 1 2 3 4 5 6 7 (reference) 8 9 10 -3.79 (-5.30; -2.28)** -2.30 (-3.74; -0.86)** -0.60 (-2.20; 1.00) -0.78 (-2.37; 0.80) -0.99 (-2.66; 0.69) -0.32 (-1.98; 1.33) 0.00 -1.30 (-2.95; 0.35) -1.11 (-2.81; 0.59) -2.77 (-4.36; -1.19)** -4.37 (-6.07; -2.67)** -3.05 (-4.67; -1.43)** -1.32 (-3.01; 0.38) -1.58 (-3.27; 0.12) -1.60 (-3.32; 0.13) -0.94 (-2.59; 0.72) 0.00 -0.71 (-2.39; 0.98) 0.43 (-1.43; 2.30) -0.38 (-2.26; 1.50) *p <.05 **p <.01

22. Page 22 The Peter Lamy Center on Drug Therapy and Aging Factors Affecting Oral Hypoglycemic Treatment Levels (or not) Full year prescription coverage has a small effect in increasing antidiabetic drug use in models 4 and 5, but loses significance in the full model 6. Lower incomes are associated with higher drug use but the effect is small and not consistently significant Significant (p =30 (0.90 to 0.93), self reported diabetes/no claim (-1.49 to -1.80), hospitalization (-2.37) Only two significant health system contact variables in model 6: any hospitalization (-2.37; p<.01), and number of different physicians seen in office visits (0.02; p <.05) Covariate control essentially eliminates the upper tail in the inverted U for level of antidiabetic drug use, but unexplained variance in the lower tail increases significantly

23. Page 23 The Peter Lamy Center on Drug Therapy and Aging Discussion: Main Points High level of heterogeneity in antidiabetic drug use Almost 1 in 4 Medicare beneficiaries with diabetes took no antidiabetic drugs in 2002 All 6 variable domains combined could explain only a small fraction of the likelihood and level of antidiabetic use among beneficiaries The inverted U pattern in medication intensity by disease burden Increasing disease burden is associated with a sharp rise in antidiabetic medication intensity among the least sick, plateaus, and then falls sharply among those with the greatest disease burden Study limitations No measure of blood glucose levels Cross-sectional design precludes causal inferences

24. Page 24 The Peter Lamy Center on Drug Therapy and Aging Conclusions: Implications for Part D Drug coverage makes no significant difference in antidiabetic drug use Quality of care and the medication intensity curve All three zones in the inverted U have potential clinical significance but require additional study - Does the low level of antidiabetic use among diabetics with the least disease burden reflect lack of need or underuse? - Does the plateau in prevalence and level of antidiabetic use among those in the middle of the range of disease burden represent a meaningful target for improving the quality of diabetic treatment in the Medicare program? - Is the sharp drop in medication use in the upper tail of the distribution of disease burden justified by new thinking about the need for glycemic control among frail older people or does it represent underuse?

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