Characteristics of older adults who meet the annual prescription drug expenditure threshold for medicare medication therapy management programs

Abstract

Background: The Medicare Modernization Act of 2003 requires drug plan sponsors to provide medication therapy management programs (MTMPs) to beneficiaries with (1) drug expenditures above $4,000, (2) multiple comorbidities, and (3) multiple prescription drugs. The Medical Expenditure Panel Survey (MEPS) is a national probability survey conducted annually by the Agency for Healthcare Research and Quality and the National Center for Health Statistics to provide nationally representative estimates of health care use, expenditures, sources of payments, and insurance coverage for the U.S. civilian noninstitutionalized population. MEPS comprises 3 components, including the household component (HC) in which households and individuals within households are sampled. The medical provider component (MPC) supplements the HC by contacting providers (hospitals, outpatient offices, home health agencies, and pharmacies) reported in the HC, and the insurance component collects data on health insurance plans and is separate from the HC.

Objective: The purpose of this study was to estimate from MEPS data for 2002-2003 (1) the proportion of older adults who may have met the $4,000 expenditure component of the MTMP criteria and (2) the patient-specific risk factors associated with meeting the $4,000 expenditure threshold.

Methods: This study is a cross-sectional analysis of MEPS respondents aged 65 years or older. Data came from both the MEPS-HC and the supplemental MEPS-MPC for 2002 and 2003. Specific data files were pooled and included the Full Year Consolidated files, Prescribed Medicines files, and the Medical Conditions files for both the 2002 and the 2003 MEPS-HC. Variables extracted from the MEPS data files included demographics, socioeconomic status, functional limitations, health status, presence and number of chronic conditions, body mass index, medical and prescription drug insurance, and health care utilization measures. The expenditure threshold of $4,000 was adjusted to $3,810 in 2003 U.S. dollars. Survey-weighted logistic regression identified factors associated with meeting the expenditure threshold. Unbiased population point estimates were obtained by adjusting for survey nonresponse, poststratification, and oversampling of blacks and Hispanics using MEPS person-level weights. In all analyses, standard errors were adjusted for nonindependence of observations due to complex multistage sampling by specifying the strata and primary sampling units for each respondent.

Results: Based on a sample of 8,035 noninstitutionalized persons aged 65 years or older in the United States, representing a population of 36.5 million older adults, MEPS data estimate that approximately 3.3 million (9.2%) incurred annual drug expenditures greater than $3,810, accounting for 35% of $55.3 billion in drug expenditures among all older adults. Older adults meeting the $3,810 prescription expenditure threshold reported an average 10.8 (SE=0.2) unique medications, 82.2 (SE=1.8) prescriptions, and 5.2 (SE=0.1) chronic conditions. Prescription expenditures accounted for 33.9% of total health care expenditures compared with 15.8% for persons who did not meet the $3,810 criterion and an average 19.5% for all persons aged 65 years or older (n=8,035). Factors that predicted meeting the expenditure threshold included age in 10-year increments (odds ratio [OR]=0.81; 95% confidence interval [CI], 0.68-0.97), requiring help with activities of daily living (OR=1.53; 95% CI, 1.19-1.97), having functional limitations (OR=1.67; 95% CI, 1.30-2.14), having TRICARE (military health care services) benefits (OR=0.54; 95% CI, 0.33-0.86), and being on Medicaid (OR=1.36; 95% CI, 1.02-1.81). Other factors that were also predictive of meeting the expenditure threshold included mental health disorders, ulcers, diabetes, dyslipidemia, cardiac disease, chronic obstructive pulmonary disorder, and the number of chronic conditions.

Conclusions: MEPS survey respondents aged 65 years or older with drug expenditures exceeding the MTMP threshold of $4,000 per year obtain substantially more drugs and have a higher disease burden than those with lower drug expenditures. Characteristics other than drug use, such as having functional limitations or requiring help with activities of daily living, can be used to identify potential MTMP candidates.