Retrospective Analysis of the Effects of Non-Compliance with Denosumab on Changes in Bone Mineral Density During the COVID-19 Pandemic

Figures & data

Table 1 Baseline Characteristics of Participants Stratified by Denosumab Injection Time

Characteristic	Time of Subsequent Injection of Denosumab			P value
	5–7 Months	7–9 Months	>9 Months
Sample size (n)	177	39	20
Age, years, mean (SD)	68.50 (9.55)	66.88 (8.62)	65.14 (8.55)	0.23
Women, % (n)	91.53% (162)	92.31% (36)	85.0% (17)	0.19
Proton pump inhibitor (PPI) use, % (n)	25.99% (46)	25.64% (10)	30.00% (6)	0.21
Selective serotonin reuptake inhibitor (SSRI) use, % (n)	5.08% (9)	7.69% (3)	5.00% (1)	0.11
Serotonin-norepinephrine reuptake inhibitor (SNRI) use, % (n)	7.91% (14)	10.26% (4)	0.00% (0)	0.26
Tricyclic antidepressant (TCA) use, % (n)	1.69% (3)	5.13% (2)	10.00% (2)	0.19
Anticonvulsants use, % (n)	14.69% (26)	17.95% (7)	15.00% (3)	0.12
Glucocorticoids use, % (n)	0% (0)	0% (0)	0% (0)
BMD, mean (SD)
Lumbar spine	0.807 (0.109)	0.782 (0.095)	0.808 (0.101)	0.25
Femoral neck	0.729 (0.081)	0.692 (0.100)	0.719 (0.105)	0.23
History of non-vertebral fracture, % (n)	22.60% (40)	20.51% (8)	10.00% (2)	0.03
History of vertebral fracture, % (n)	29.38% (52)	30.77% (12)	35.00% (7)	0.03

Table 2 Characteristics of Participants Stratified After Two Denosumab Injections

Characteristic	Time of Subsequent Injection of Denosumab			P value
	5–7 Months	7–9 Months	>9 Months
BMD, mean (SD)
Lumbar spine	0.847 (0.099)	0.823 (0.095)	0.829 (0.091)	0.31
Femoral neck	0.774 (0.089)	0.749 (0.092)	0.760 (0.102)	0.29
Incident non-vertebral fracture, % (n)	2.82% (5)	2.56% (1)	0.00% (0)	0.02
Incident vertebral fracture, % (n)	0.56% (1)	0.00% (0)	0.00% (0)	0.04
Mean duration of treatment from baseline injection in months (SD)	6.11 (0.66)	7.95 (0.58)	11.15 (1.26)	0.01

Table 3 Regression Analysis Comparing Bone Mineral Density (BMD) Change Between Groups [Reference Group: 5–7 Months]*

Groups: Time Between 1st and 2nd Injection Was		Estimate	95% Confidence Limits
Lumbar spine	Between 7–9 months	0.0007	−0.0024 to 0.0031
	More than 9 months	−0.0191	−0.0083 to −0.0305
Femoral neck	Between 7–9 months	0.0068	−0.0155 to 0.0319
	More than 9 months	−0.0044	−0.0151 to 0.0067

Notes: *All multivariate regression analyses were adjusted for baseline BMD values, patient age, drugs with or without proton pump inhibitors, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, tricyclic antidepressants, anticonvulsants, and the number of months between the initial and subsequent BMD after two denosumab injections.