Trajectory of Excess Medical Expenditures 10 Years Before and After Diabetes Diagnosis Among U.S. Adults Aged 25-64 Years, 2001-2013

Abstract

Objective: We assessed the excess medical expenditures for adults newly diagnosed with diabetes, for up to 10 years before and after diabetes diagnosis.

Research design and methods: Using the 2001-2013 MarketScan data, we identified people with newly diagnosed diabetes among adults aged 25-64 years (diabetes cohort) and matched them with people who did not have diagnosed diabetes (control cohort) using 1:1 propensity score matching. We followed these two cohorts up to ±10 years from the index date, with annual matched cohort sizes ranging from 3,922 to 39,726 individuals. We estimated the yearly and cumulative excess medical expenditures of the diabetes cohorts before and after the diagnosis of diabetes.

Results: The per capita annual total excess medical expenditure for the diabetes cohort was higher for the entire 10 years prior to their index date, ranging between $1,043 in year -10 and $4,492 in year -1. Excess expenditure spiked in year 1 ($8,109), declined in year 2, and then increased steadily, ranging from $4,261 to $6,162 in years 2-10. The cumulative excess expenditure for the diabetes cohort during the entire 20 years of follow-up was $69,177 ($18,732 before and $50,445 after diagnosis).

Conclusions: People diagnosed with diabetes had higher medical expenditures compared with their counterparts, not only after diagnosis but also up to 10 years prior to diagnosis. Managing risk factors for type 2 diabetes and cardiovascular disease before diagnosis, and for diabetes-related complications after diagnosis, could alleviate medical expenditure in people with diabetes.

Figure 1—

Mean total and excess medical expenditures during the 10 years before and after the index date (diabetes diagnosis) by cohort. The expenditures in follow-up year 1 also include the cost incurred on the day of diagnosis if diagnosed in outpatient setting or the cost incurred for whole admission if diagnosed in inpatient setting. The control cohort includes people not diagnosed with diabetes during the study period. Excess = average expenditures for diabetes cohort – average expenditures for control cohort. All the excess medical expenditures are statistically significant (P < .05, paired Student t test).

Figure 2—

Mean cumulative total and excess medical expenditures during the 10 years before and after the index date by cohort. The expenditures in follow-up year 1 also include the cost incurred on the day of diagnosis if diagnosed in outpatient setting or the cost incurred for whole admission if diagnosed in inpatient setting. The control cohort includes people not diagnosed with diabetes during the study period. Excess = average expenditures for diabetes cohort – average expenditures for control cohort.

Figure 3—

Mean excess medical expenditures during the 10 years before and after the index date by medical expenditure component. The expenditures in follow-up year 1 also include the cost incurred on the day of diagnosis if diagnosed in outpatient setting or the cost incurred for whole admission if diagnosed in inpatient setting. The control cohort includes people not diagnosed with diabetes during the study period. Excess = average expenditures for diabetes cohort – average expenditures for control cohort. All the excess medical expenditures are statistically significant (P < 0.05, paired Student t test), except for the outpatient and inpatient expenditures in follow-up year −10.