Incidence of Skeletal-Related Events in Patients with Castration-Resistant Prostate Cancer: An Observational Retrospective Cohort Study in the US

Table 4

Incidence rates of SREs among all person-time and stratified by initial bone-targeted agent use and history of SRE before cohort entry.

Person-Time Included	Patients	Person-Months	Cases	Incidence Rate per 100 Person-Months; (95% CI)
All person-time (primary analysis)	2,234	23,716	896	3.78 (3.53-4.03)
Bone-targeted agent use (secondary analysis)
Person-time before any use	1,021	7,429	309	4.16 (3.71-4.65)
Person-time after any use	1,539	16,287	587	3.60 (3.32-3.91)
History of SRE before cohort entry (secondary analysis)
Patients with no history of SRE	982	11,549	385	3.33 (3.01-3.68)
Patients with history of SRE	1,252	12,167	511	4.20 (3.84-4.58)

CI = confidence interval. SRE = skeletal-related event.
Note. The sum of patients contributing person-time before use of any bone-targeted agent and after use of any bone-targeted agent is greater than the total number of patients, as patients may have contributed person-time to both groups (see methods for details).