Healthcare utilization and direct medical cost in the years during and after cancer diagnosis in patients with type 2 diabetes mellitus.

AIMS/INTRODUCTION There is uncertainty about the direct medical costs of type 2 diabetes mellitus (T2DM) patients with cancers. MATERIALS AND METHODS A population-based retrospective cohort of 99915 T2DM patients from Hong Kong Hospital Authority between 2006 and 2017 was assembled. 16869 patients who had initial cancer diagnosis after T2DM were matched with 83046 patients without cancer (controls) using a matching ratio up to one-to-five propensity score-matching method. Patients were divided into four categories according to life expectancy. Healthcare service utilization and direct medical costs during the index year, subsequent years, and mortality year were compared between patients with and without cancer in each category. RESULTS Medical costs of cancer patients in index year ranged from US$27533 for patients died 3 years. Cancer patients had significantly greater expenditures than controls in index year (all P 3 years after index year (US$32558 vs. US$28260). For patients in both groups, patients who survived >3 years had significantly lower costs than those died 90% of the medical costs for both groups in mortality year. CONCLUSIONS T2DM patients with cancers incurred greater medical costs in the diagnosis, ensuing, and mortality years than T2DM patients without cancers.