On-time denosumab dosing recovered rapidly during the COVID-19 pandemic, yet remains suboptimal.

Timely administration of denosumab every 6 mo is critical in osteoporosis treatment to avoid multiple vertebral fracture risk upon denosumab discontinuation or delay. This study aimed to estimate the immediate and prolonged impact of the COVID-19 pandemic on the timing of denosumab doses. We identified older adults (≥66 yr) residing in the community who were due to receive denosumab between January 2016 and December 2020 using Ontario Drug Benefit data. We completed an interrupted time-series analysis to estimate the impact of the COVID-19 pandemic (March 2020) on the monthly proportion of on-time denosumab doses (183 +/-30 d). Analyses were stratified by user type: patients due for their second dose (novice users), third or fourth dose (intermediate users), or ≥5th dose (established users). In additional analyses, we considered patients living in nursing homes, switching to other osteoporosis drugs, and reported trends until February 2022. We studied 148 554 patients (90.9% female, mean [SD] age 79.6 [8.0] yr) receiving 648 221 denosumab doses. The average pre-pandemic proportion of on-time therapy was steady in the community, yet differed by user type: 64.9% novice users, 72.3% intermediate users, and 78.0% established users. We identified an immediate overall decline in the proportion of on-time doses across all user types at the start of the pandemic: -17.8% (95% CI, -19.6, -16.0). In nursing homes, the pre-pandemic proportion of on-time therapy was similar across user types (average 83.5%), with a small decline at the start of the pandemic: -3.2% (95% CI, -5.0, -1.2). On-time therapy returned to pre-pandemic levels by October 2020 and was not impacted by therapy switching. Although on-time dosing remains stable as of February 2022, approximately one-fourth of patients in the community do not receive denosumab on-time. In conclusion, although pandemic disruptions to denosumab dosing were temporary, levels of on-time therapy remain suboptimal.