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Mortality and Life Expectancy

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Survival rates for individuals with SCI have made steady improvements over the past five decades. Prior to World War II life expectancy for individuals with SCI was quite poor (Geisler et al. 1983). Leading causes of death were those resulting from renal failure and infection (Lammertse 2001).  Since the introduction of antibiotics, improved emergency transportation, advances in long-term health interventions, and the availability of preventative care at specialized treatment centres, mortality rates have been steadily decreasing and the causes of death have begun to mirror those of the general population (Whiteneck et al. 1992; DeVivo et al. 1999). However, life expectancy is still diminished compared to the general population (Whiteneck et al. 1992; Hartkopp et al. 1997; McColl et al. 1997; Frankel et al. 1998; DeVivo et al. 1999; Yeo et al. 2000; Krause et al. 2004).

Causes of death among individuals with SCI and those in the general population appear to be similar. In 2011, the two leading causes of death in high- and middle-income countries for the general population were ischemic heart disease and stroke (WHO 2011).  Other common causes were tracheal bronchus and lung cancers, chronic obstructive pulmonary disease, lower respiratory infections, and Alzheimer’s disease and other dementias (WHO 2011). Similarly, two leading causes of death in the SCI population are respiratory complications and heart disease (Hartkopp et al.1997; Frankel et al.1998; DeVivo et al. 1999; Soden et al. 2000; Zeilig et al. 2000; Garshick et al. 2005).  Additionally, the latest report from the National Spinal Cord Injury Database (NSCIDB) indicates the main causes of death in persons with SCI in the United States are pneumonia and septicemia (NSCISC 2013).  The high rates of cardiovascular disease in the SCI population may be partly due to physiological and functional changes following injury (Dearwater et al. 1986; Yekutiel et al. 1989; Bauman et al. 1992a, b; Gupta 2006). Interestingly, cancer is a growing cause of death in persons with SCI (DeVivo et al. 1999; Zeilig et al. 2000; Imai et al. 2004).

In general, it appears that as individuals with SCI age, cause of death becomes similar to age matched controls (Capoor & Stein 2005).  Some deaths, however, may occur prematurely (e.g., from cardiovascular disease; Yekutiel et al. 1995), and there are some notable differences in mortality patterns between the SCI and the general populations.

In this section, 5 longitudinal studies and 1 cross-sectional study (see Table 1) on mortality and life expectancy among individuals with spinal cord injury are reviewed.

Table 1:  Mortality and Life-Expectancy

Discussion

Rabadi et al. (2013) reported a 10-year survival rate of 87% from time of injury and a mean age of injury of 39. Pickelsimer and colleagues (2010) reported a 10-year survival rate of 84.5% from time of injury with a mean age of injury of 41 and excuded those that died in the first 89 days.

Although Samsa et al. (1993) found that injury level was not a significant predictor for mortality, they noted a near significant effect (p=0.06) for complete cervical injuries compared to all other injuries. Similarly, in an 11-year longitudinal study, Cao et al. (2013) reported the likelihood of death in individuals with injuries at the C1-4 levels to be 1.6 times greater than for individuals with injuries at other levels. Several studies have found no association between impairment and mortality (e.g. Liang et al. 2001; Imai et al. 2004; Garshick et al. 2005), whereas other studies have highlighted the importance of impairment as a prognostic factor (Whiteneck et al. 1992; McColl et al. 1997; Coll et al. 1998; DeVivo et al. 1999; Soden et al. 2000; Yeo et al. 2000; Strauss et al. 2006).  Samsa and colleagues (1993) found age of onset to be a significant predictor of long-term survival, which is consistent with other longitudinal studies that did not meet our inclusion criteria (Whiteneck et al. 1992; Frankel et al. 1998).  Rabadi et al. (2013) reported age of onset to be the only predictor of mortality.

With regards to causes of mortality, Samsa et al. (1993) found that diseases of the genitourinary system (i.e. renal failure, septicemia) disproportionately accounted for death in their SCI sample, but the patterns of death began to approach that of the general population by 20 years post-injury.  For instance, the rates of circulatory disease and neoplasms steadily increased across time points.  Interestingly, the causes of death due to injury and poisoning, and external conditions were the highest at 3-months to 5 years post-SCI, and steadily decreased across time points.  In a 12-year longitudinal study of 147 veterans with SCI, Rabadi et al. (2013) reported infection, cardiovascular, and cancer to be the three primary causes of death.  Although not discussed, causes of death may have also included suicides.  Regardless, the findings of lower levels of evidence highlighting the high rates of suicide as a cause of death (i.e. Imai et al. 2004) reinforces the need to provide psychosocial services to help minimize the occurrence of suicide in persons with SCI.

An acknowledged limitation of the study by Samsa et al. (1993) is the reliance on secondary data sources for case identification, control selection, and mortality assessment.  The study was also only on male veterans and did not include women or persons who did not survive acute SCI (i.e. less than 3 months post-SCI).Causes of death were not reported by Pickelsimer et al. (2010) or by Savic et al. (2010).

Conclusion

There is level 4 evidence that the 10 year survival rate post injury is 84-87% (Rabadi et al. 2013; Pickelsimer et al. 2010).

There is Level 4 evidence (Frisbie 2010) that the mortality rate post-SCI over a 10-year period may be 15.5% to 25.8%, and level 4 evidence (Cao et al. 2013) that the mortality rate is higher for individuals with SCI than the general population.

There is Level 4 evidence (Cao et al. 2013) that mortality may be higher for persons with SCIs at the C1-4 level than other spinal cord levels.

There is Level 4 (Frisbie 2010) to Level 5 evidence (Samsa et al. 1993) that the causes of death post-SCI are beginning to approximate those of the general population.

There is Level 4 and 5 evidence (Samsa et al. 1993; Cao et al. 2013) that life expectancy for males with SCI is lower than the general male population.

There is level 4 evidence (Rabadi et al. 2013) that older age at time of injury is a predictor of SCI-related mortality.

  • Life expectancy for males with SCI is likely lower than the general male population.

    Persons injured at a younger age will likely have a longer life expectancy than persons injured at an older age.

    Causes of death post-SCI may be similar to those of the general population.