Treatment indications and potential off-label use of antidepressants among older adults: A population-based...

Off-label prescriptions of antidepressants may be of special concern in older-adults. We aimed to study the potential off-label use of antidepressants among adults ≥65 years by describing the patterns, trends, and factors associated with missing and unspecified treatment indications.

We used registry data to describe indications of all antidepressant prescriptions (N = 13.8 million) redeemed by older-adults in 2006-2019. We investigated factors associated with off-label use by considering prescriptions with missing and unspecified indications of the first antidepressant prescription using a multinomial logistic regression with the 'depression' indication as a reference category and reported odds ratios (ORs) with 95% confidence intervals (CI).

Overall, 18.1% of all antidepressant prescriptions had missing indications, and 9.9% had unspecified indications. The proportion of potential off-label use based on missing and unspecified prescriptions remained mostly consistent during 2006-2019. We identified similar associations in user characteristics whether considering missing or unspecified first prescription. ORs with 95% CI were raised in non-western ethnicity (vs. Danish, 1.12 (0.99-1.26) for missing indication and 1.28 (1.11-1.48) for unspecified indication) and female sex (vs. male, 1.05 (1.02-1.07) and 1.05 (1.02-1.07) respectively). ORs were reduced for shorter educational attainment (vs. long, 0.90 (0.87-0.94) and 0.92 (0.88-0.96)), older age (≥81 vs. 67-70 years, 0.66 (0.65-0.71) and 0.73 (0.70-0.76)) and hospital psychiatric diagnosis (per diagnosis 0.76 (0.73-0.78) and 0.88 (0.86-0.91)).

Nearly one-third of all antidepressant prescriptions redeemed by older-adults in Denmark had either missing or unspecified treatment indications. Whether these prescriptions were actual off-label use needs to be validated. Clinicians should pay special attention to patients' characteristics linking missing and unspecified indications and maintain adequate documentation while prescribing medication.