Long-term prognosis and causes of death after spondylodiscitis: A Danish nationwide cohort study.
BACKGROUND
Data on long-term prognosis after spondylodiscitis are scarce. The purpose of this study was to determine long-term mortality and the causes of death after spondylodiscitis.


METHODS
A nationwide, population-based cohort study using national registries of patients diagnosed with non-post-operative pyogenic spondylodiscitis from 1994-2009, alive 1 year after diagnosis (n = 1505). A comparison cohort from the background population individually matched for sex and age was identified (n = 7525). Kaplan-Meier survival curves were constructed and Poisson regression analyses used to estimate mortality rate ratios (MRR).


RESULTS
Three hundred and sixty-five patients (24%) and 1115 individuals from the comparison cohort (15%) died. Unadjusted MRR for spondylodiscitis patients was 1.76 (95% CI = 1.57-1.98) and 1.47 (95% CI = 1.30-1.66) after adjustment for comorbidity. No deaths were observed in 128 patients under the age of 16 years. Siblings of patients did not have increased long-term mortality compared with siblings of the individuals from the comparison cohort. This study observed increased mortality due to infections (MRR = 2.57), neoplasms (MRR = 1.40), endocrine (MRR = 3.72), cardiovascular (MRR = 1.62), respiratory (MRR = 1.71), gastrointestinal (MRR = 3.35), musculoskeletal (MRR = 5.39) and genitourinary diseases (MRR = 3.37), but also due to trauma, poisoning and external causes (MRR = 2.78), alcohol abuse-related diseases (MRR = 5.59) and drug abuse-related diseases (6 vs 0 deaths, MRR not calculable).


CONCLUSIONS
Patients diagnosed with spondylodiscitis have increased long-term mortality, mainly due to comorbidities, particularly substance abuse.
a Department of Infectious Diseases , Rigshospitalet, Copenhagen University Hospital , Copenhagen , Denmark.|b Department of Pulmonary and Infectious Diseases , Nordsjællands Hospital, Copenhagen University Hospital , Hillerød , Denmark.
Theis
T
Aagaard
a Department of Infectious Diseases , Rigshospitalet, Copenhagen University Hospital , Copenhagen , Denmark.|b Department of Pulmonary and Infectious Diseases , Nordsjællands Hospital, Copenhagen University Hospital , Hillerød , Denmark.
Casper
C
Roed
c Department of Orthopaedic Surgery , Spine Unit, Rigshospitalet, Copenhagen University Hospital , Copenhagen , Denmark.
Benny
B
Dahl
a Department of Infectious Diseases , Rigshospitalet, Copenhagen University Hospital , Copenhagen , Denmark.
Niels
N
Obel
D000293:Adolescent; D000328:Adult; D002423:Cause of Death; D015331:Cohort Studies; D015897:Comorbidity; D003718:Denmark / Q000453:epidemiology; D015299:Discitis / Q000401:mortality*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D011379:Prognosis; D012042:Registries; D012044:Regression Analysis; D019966:Substance-Related Disorders / Q000401:mortality*; D055815:Young Adult
Kaplan-Meier; Mortality; Poisson; alcohol; causes of death; cohort; comorbidities; comorbidity; death; discitis; family-related; mortality rate ratio; prognosis; pyogenic; risk factors; siblings; spondylodiscitis; substance abuse; vertebral osteomyelitis