The objective of this study was to evaluate the impact of medication adherence on
healthcare utilization and cost for 4 chronic conditions that are major drivers of
drug spending: diabetes, hypertension, hypercholesterolemia, and congestive heart
failure.
The authors conducted a retrospective cohort observation of patients who were continuously
enrolled in medical and prescription benefit plans from June 1997 through May 1999.
Patients were identified for disease-specific analysis based on claims for outpatient,
emergency room, or inpatient services during the first 12 months of the study. Using
an integrated analysis of administrative claims data, medical and drug utilization
were measured during the 12-month period after patient identification. Medication
adherence was defined by days' supply of maintenance medications for each condition.
The study consisted of a population-based sample of 137,277 patients under age 65.
Disease-related and all-cause medical costs, drug costs, and hospitalization risk
were measured. Using regression analysis, these measures were modeled at varying levels
of medication adherence.
For diabetes and hypercholesterolemia, a high level of medication adherence was associated
with lower disease-related medical costs. For these conditions, higher medication
costs were more than offset by medical cost reductions, producing a net reduction
in overall healthcare costs. For diabetes, hypercholesterolemia, and hypertension,
cost offsets were observed for all-cause medical costs at high levels of medication
adherence. For all 4 conditions, hospitalization rates were significantly lower for
patients with high medication adherence.
For some chronic conditions, increased drug utilization can provide a net economic
return when it is driven by improved adherence with guidelines-based therapy.