Drug dispensings among elderly in the year before colon cancer diagnosis versus matched cancer-free controls.

Abstract

The concomitant use of multiple drugs is common among the general population of elderly. The aim of this study was to provide an overview of which drugs are dispensed to elderly in the year before colon cancer diagnosis and to compare this with cancer-free controls. Data from the Eindhoven Cancer Registry were linked to the PHARMO Database Network. Patients with colon cancer aged ≥70years were included and matched with controls on gender, year of birth and postal code. Proportions of cases and controls with ≥1 dispensing of each WHO ATC-2-level drug during the total year and during each quarter of the year were calculated and differences between cases and controls tested. Proportion of cases with ≥1 drug dispensing was highest for drugs for constipation (cases vs. controls 58% vs. 10%), antithrombotics (42% vs. 33%), drugs for acid-related disorders (35% vs. 22%), antibacterials (34% vs. 24%), agents acting on the renin-angiotensin system (33% vs. 27%), beta-blockers (33% vs. 23%), lipid-modifying agents (29% vs. 22%), diuretics (29% vs. 21%), psycholeptics (25% vs. 18%) and antianaemics (23% vs. 6%). The proportion of cases with ≥1 drug dispensing increased from the first to the last quarter of the year for drugs for constipation (7%-53%), drugs for acid-related disorders (16%-27%), antibacterials (12%-16%), beta-blockers (26%-28%), psycholeptics (15%-19%) and antianaemics (6%-18%). Elevated proportions of cases with ≥1 drug dispensing for several drugs are mostly related to comorbidity, although increasing proportions of cases with ≥1 drug dispensing for certain drugs during the year can be attributed to the incidence of colon cancer. We have provided insight into which drugs are commonly used in the year preceding colon cancer diagnosis. This may trigger general practitioners and medical specialists to further evaluate the patient.