Selective serotonin reuptake inhibitors and osteoporosis: a target trial emulation using real-world data.

Objectives: Selective serotonin reuptake inhibitors (SSRIs) have been associated with increased risk of osteoporosis, and sertraline may be more potent than citalopram in this regard. Here, target trial emulation was used to investigate whether sertraline, citalopram and escitalopram (the S-enantiomer of citalopram) differentially affect the risk of osteoporosis. Subsequently, it was examined whether SSRIs increase the risk of osteoporosis in a dose-response-like manner.

Methods: Danish nationwide registers were used to identify all individuals that initiated treatment for depression with sertraline, citalopram, or escitalopram between January 1, 2007, and March 1, 2019. These individuals were followed until development of osteoporosis, death, or end of follow-up. Cox proportional hazards regression was used to adjust for relevant baseline covariates to emulate randomised treatment allocation to compare the rate of osteoporosis for individuals treated with sertraline, citalopram or escitalopram. Subsequently, the cumulative dose of sertraline, citalopram, and escitalopram was calculated, and Cox proportional hazards regression was used to assess dose-response-like relationships with osteoporosis.

Results: We identified 27,280, 65,529, and 17,703 individuals initiating treatment with sertraline, citalopram, and escitalopram, respectively. There was no material or statistically significant differential risk of osteoporosis between these groups (adjusted hazard rate ratio, aHRR = 0.98 for citalopram versus sertraline and aHRR = 0.94 for escitalopram versus sertraline). The results were not indicative of the SSRIs having a dose-response-like effect on osteoporosis risk.

Conclusions: Sertraline, citalopram and escitalopram do not appear to differentially affect the risk of osteoporosis. The lack of clear dose-response-like relationships suggest that they do not have a causal effect on osteoporosis risk.