Differences in healthcare expenditure estimates according to statistical approach: A nationwide claims database study...

Disease-associated healthcare expenditures are generally calculated using matched comparisons or regression-based analyses, but little is known about their differences in estimates. This aim of this study was to compare the differences between disease-associated healthcare expenditures estimated using these 2 methods.

In this retrospective cohort study, a matched comparison was first conducted by matching cases with controls using sex, age, and comorbidities to estimate disease-associated expenditures. The cases were then used in a fixed-effects analysis that compared expenditures before and after disease occurrence. The subjects were adults (≥20 years) with primary hepatocellular carcinoma (HCC) who underwent treatment (including surgical resection, locoregional therapy, transcatheter arterial chemoembolization, and transarterial embolization) at a Japanese hospital between April 2010 and March 2018. We calculated the total healthcare expenditures per patient per month according to treatment and disease phase (initial, continuing, and terminal).

There were 14,923 cases in the initial/continuing phases and 15,968 cases in the terminal phase. In the initial/continuing phases, 3,552 patients underwent surgical resection only, with HCC-associated expenditures of $5,555 according to the matched comparison and $5,889 according to the fixed-effects analysis (proportional difference: 94.3%). The initial phase expenditures were approximately 9% higher in the fixed-effects analysis, whereas the continuing phase expenditures were approximately 7% higher in the matched comparison. The expenditures in the terminal phase were 93.1% higher in the fixed-effects analysis.

The 2 methods produced similar estimates of HCC-associated healthcare expenditures in the initial/continuing phases. However, terminal phase expenditures were substantially different between the methods.