Mortality and Cause of Death in Patients With Vertebral Fractures

A Longitudinal Follow-Up Study Using a National Sample Cohort

Hyo Geun Choi, MD; Joon Kyu Lee, MD, PhD; Songyong Sim, PhD; Miyoung Kim, MD, PhD

Disclosures

Spine. 2020;45(5):E280-E287. 

In This Article

Results

The mean follow-up durations were 58.8 months (standard deviation SD = 40.3 mo) in the vertebral fracture group and 60.3 months (SD = 40.3 mo) in the control group. The median follow-up durations in the vertebral fracture and control groups were 53 and 55 months, respectively (interquartile range: 24–91 mo and 25–93 mo, respectively). The survival rate through the study period is depicted in Figure 2.

Figure 2.

Kaplan–Meier survival analysis for the mortality of the vertebral fracture group and the control group.

Age, sex, income level, and region of residence were matched between the vertebral fracture and control groups (Table 1). In the vertebral facture and control groups, 17.2% (3,739/21,759) and 13.6% (11,844/87,036) of participants, respectively, died during the follow-up period (P < 0.001).

The crude and adjusted HRs for mortality were 1.31 (95% confidence interval [CI] = 1.26–1.36) and 1.21 (95% CI = 1.17–1.26), respectively, in the vertebral fracture group (Table 2); this group showed increased crude and adjusted HRs for mortality across all age- and sex-based subgroups. The adjusted HR was highest in patients aged less than 60 years (1.50; 95% CI = 1.26–1.78), lower in those aged 60 to 69 years (1.34; 95% CI = 1.21–1.47), and lowest in those aged more than or equal to 70 years (1.18; 95% CI = 1.13–1.23). The adjusted HR was 1.45 (95% CI = 1.40–1.55) in men and 1.12 (95% CI = 1.07–1.17) in women.

Analysis of mortality rates according to the cause of death (Table 3) revealed an odds ratio (OR) for overall death of 1.32 (95% CI = 1.26–1.37) in the vertebral fracture group. Mortalities caused by neoplasms, neurologic diseases, circulatory diseases, respiratory diseases, digestive diseases, diseases in musculoskeletal system and connective tissue, and trauma were higher in the vertebral fracture group than in the control group (false discovery rate-adjusted P < 0.05 for each). The ORs of mortality were highest for disease in musculoskeletal system and connective tissue (3.14; 95% CI = 2.29–4.31) followed by digestive disease (1.78; 95% CI = 1.48–2.15), respiratory disease (1.70; 95% CI = 1.51–1.91), and trauma (1.68; 95% CI = 1.47–1.93).

The detailed causes of death are presented in Supplementary Table 1, https://links.lww.com/BRS/B473. Among disease in musculoskeletal system and connective tissue, disorders of bone density and structure were the most common cause of death in the vertebral fracture group, comprising 1.15% of deaths (43/3739), as well as in the control group, comprising 0.32% of deaths (38/11,844). Among digestive diseases, diseases of liver were the most common cause of death in the vertebral fracture group, comprising 1.93% of deaths (72/3739), as well as in the control group, comprising 1.27% of deaths (150/11,844). Among respiratory diseases, chronic lower respiratory diseases along with influenza and pneumonia were the two most common causes of death: chronic lower respiratory diseases comprised 4.49% of deaths (168/3739) in the vertebral fracture group and 3.06% of deaths (362/11,844) in the control group; influenza and pneumonia comprised 4.31% of deaths (161/3,739) in the vertebral fracture group and 3.66% of deaths (433/11,844) in the control group. Among trauma, toxic effects of substances chiefly nonmedical as to source were the most common cause of death, comprising 1.44% of deaths (54/3739) in the vertebral fracture group and 1.95% of deaths (133/11,844) in the control group.

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