Cervical Spinal Fracture and Other Diagnoses Associated With Mortality in Hospitalized Ankylosing Spondylitis Patients

Incidence Rate and Factors Associated With Fractures Among Medicare Beneficiaries With Ankylosing Spondylitis in the United States

OBJECTIVE

We evaluated the incidence rate and factors associated with fractures among adults with ankylosing spondylitis (AS).

METHODS

We performed a retrospective cohort study with data from the Rheumatology Informatics System for Effectiveness registry linked to Medicare claims from 2016 to 2018. Patients were required to have two AS International Classification of Diseases codes 30 or more days apart and a subsequent Medicare claim. Then, 1 year of baseline characteristics were included, after which patients were observed for fractures. First, we calculated the incidence rate of fractures. Second, we constructed logistic regression models to identify factors associated with the fracture, including age, sex, race and ethnicity, body mass index, Medicare/Medicaid dual eligibility, area deprivation index, Charlson comorbidity index, smoking status, osteoporosis, historical fracture, and use of osteoporosis treatment, glucocorticoids, and opioids.

RESULTS

We identified 1,426 adults with prevalent AS. Mean ± SD age was 69.4 ± 9.8 years, 44.3% were female, and 77.3% were non-Hispanic White. Fractures occurred in 197 adults with AS. The overall incidence rate of fractures was 76.7 (95% confidence interval [CI] 66.4-88.6) per 1,000 person-years. Older age (odds ratio [OR] 2.8, 95% CI 1.39-5.65), historical fracture (OR 5.24, 95% CI 3.44-7.99), and use of more than 30 mg morphine equivalent (OR 1.86, 95% CI 1.08-3.19) conferred increased odds of fracture.

CONCLUSIONS

In this large sample of Medicare beneficiaries with AS, increasing age, historical fracture, and use of opioids had higher odds of fracture. Men and women were equally likely to have a fracture. Because opioid use was associated with fracture in AS, this high-risk population should be considered for interventions to mitigate risk.

Mortality and Ankylosing Spondylitis in the US population: leading causes and associated factors

OBJECTIVE

Ankylosing Spondylitis (AS) is a chronic inflammatory condition that affects the axial skeleton. Recent studies have shown that mortality risk is higher in AS patients and that it is possibly related to disease activity and duration. Our aim was to investigate the leading causes and factors associated with mortality in hospitalized AS patients in the USA.

METHODS

This is a case-control study using the Cerner Health Facts® database between 2015 and 2017. The search was done using ICD codes and administrative claims. Cases were hospitalized AS patients who died during that hospitalization, while controls were patients who survived. In addition to demographics, we collected data on the inpatient use of medications such as NSAIDs, as well as different comorbidities and systemic disease manifestations. The discharge diagnoses for deceased patients were collected to infer causes of mortality. Analysis of association was performed using chi-square tests, t-tests, Wilcoxon rank-sum tests, and logistic regression methods.

RESULTS

The leading causes of death were cardiovascular, infectious, respiratory, and traumatic. The Elixhauser comorbidity index was the factor most associated with mortality (p-value < 0.0001), with congestive heart failure and renal disease the most contributing. Drug use disorder was associated with mortality (adjusted OR = 10.9; p = 0.001). Inpatient NSAIDs use was not associated with increased odds for mortality (p-value 0.33).

CONCLUSION

Cardiovascular and renal comorbidities are associated with mortality and need to be targeted early on to lower the odds of mortality as patients age. Strategies to prevent opioid and drug abuse should be strengthened in the AS population. Key Points • Cardiovascular and renal comorbidities are associated with mortality and need to be screened for and targeted early on to lower the odds of mortality as patients age. • Drug use disorder including opioid dependence is associated with mortality, and strategies to prevent opioid and drug abuse should be strengthened in the AS population.

Trends in Fracture Rates Over Two Decades Among Veterans With Ankylosing Spondylitis

OBJECTIVE

There is an increased risk of fracture in individuals with ankylosing spondylitis (AS) compared to the general population, possibly due to systemic inflammatory effects. The use of tumor necrosis factor inhibitors (TNFi) may reduce fracture risk by inhibiting inflammation. We assessed fracture rates in AS versus non-AS comparators and whether these rates have changed since the introduction of TNFi.

METHODS

We used the national Veterans Affairs database to identify adults ≥18 years old with ≥1 International Classification of Diseases, Ninth Revision (ICD-9)/ICD-10 code for AS and at least 1 disease-modifying antirheumatic drug prescription. As comparators, we selected a random sample of adults without AS diagnosis codes. We calculated fracture incidence rates for AS and comparators, with direct standardization to the cohort structure in 2017. To compare fracture rates from 2000 to 2002 (pre-TNFi) versus 2004-2020 (TNFi era), we performed an interrupted time series analysis.

RESULTS

We included 3,794 individuals with AS (mean age 53 years, 92% male) and 1,152,805 comparators (mean age 60 years, 89% male). For AS, the incidence rate of fractures increased from 7.9/1,000 person-years in 2000 to 21.6/1,000 person-years in 2020. The rate also increased among comparators, although the ratio of fracture rates (AS/comparators) remained relatively stable. In the interrupted time series, the fracture rate for AS patients in the TNFi era was nonsignificantly increased compared to the pre-TNFi era.

CONCLUSION

Fracture rates have increased over time for both AS and non-AS comparators. The fracture rate in individuals with AS did not decrease after TNFi introduction in 2003.

No evidence of a causal relationship between ankylosing spondylitis and cardiovascular disease: a two-sample Mendelian randomization study

Objective

Observational studies have suggested an increased risk of cardiovascular disease in individuals with ankylosing spondylitis. However, these studies are prone to confounding factors and reverse causality. To address these limitations, we conducted a Mendelian randomization study to assess the causal relationship between AS and CVD.

Methods

The study population comprises 9,069 individuals with ankylosing spondylitis and 509,093 individuals with either of six common cardiovascular diseases and a related indicator. Causal analysis using summary effect estimates and inverse variance weighting were employed as the main methods.

Results

The CAUSE analysis showed no evidence of a causal relationship between AS and CVD. The odds ratios for total CVD, heart failure, myocardial infarction, valvular heart disease, ischemic heart disease, and venous thromboembolism, Arterial stiffness index, were as follows: OR, 1.01; 95% confidence interval, 0.96-1.05; P = 0.91; OR, 1.03; 95% CI, 0.99-1.08; P = 0.50; OR, 0.94; 95% CI, 0.86-1.03; P = 0.53; OR, 0.99; 95% CI, 0.94-1.04; P = 0.99; OR, 0.98; 95% CI, 0.91-1.04; P = 0.94; OR, 0.98; 95% CI, 0.91-1.04; P = 0.99; β, -0.0019; 95% CI, 0.97-1.01; P = 0.99. The IVW and weighted median methods also yielded consistent results, and no heterogeneity or pleiotropy was found. Likewise, a reverse Mendelian randomization analysis did not uncover a heritable causal relationship between AS and CVD.

Conclusion

This Mendelian randomization study does not support a causal relationship between AS and CVD. Further research is needed to confirm this association.

Can a Nomogram Predict Survival After Treatment for an Ankylosing Spondylitis Cervical Fracture in a Patient With Neurologic Impairment? A National, Multicenter Study

BACKGROUND

Ankylosing spondylitis-related cervical spine fracture with neurologic impairment (ASCF-NI) is a rare but often lethal injury. Factors independently associated with survival after treatment remain poorly defined, and identifying patients who are likely to survive the injury remains challenging.

QUESTIONS/PURPOSES

(1) What factors are independently associated with survival after treatment among patients with ASCF-NI? (2) Can a nomogram be developed that is sufficiently simple for clinicians to use that can identify patients who are the most likely to survive after injury?

METHODS

This retrospective study was conducted based on a multi-institutional group of patients admitted and treated at one of 29 tertiary hospitals in China between March 1, 2003, and July 31, 2019. A total of 363 patients with a mean age of 53 ± 12 years were eventually included, 343 of whom were male. According to the National Household Registration Management System, 17% (61 of 363) died within 5 years of injury. Patients were treated using nonsurgical treatment or surgery, including procedures using the anterior approach, posterior approach, or combined anterior and posterior approaches. Indications for surgery included three-column injury, unstable fracture displacement, neurologic impairment or continuous progress, and intervertebral disc incarceration. By contrast, patients generally received nonsurgical treatment when they had a relatively stable fracture or medical conditions that did not tolerate surgery. Demographic, clinical, and treatment data were collected. The primary study goal was to identify which factors are independently associated with death within 5 years of injury, and the secondary goal was the development of a clinically applicable nomogram. We developed a multivariable Cox hazards regression model, and independent risk factors were defined by backward stepwise selection with the Akaike information criterion. We used these factors to create a nomogram using a multivariate Cox proportional hazards regression analysis.

RESULTS

After controlling for potentially confounding variables, we found the following factors were independently associated with a lower likelihood of survival after injury: lower fracture site, more-severe peri-injury complications, poorer American Spinal Injury Association (ASIA) Impairment Scale, and treatment methods. We found that a C5 to C7 or T1 fracture (ref: C1 to C4 and 5; hazard ratio 1.7 [95% confidence interval 0.9 to 3.5]; p = 0.12), moderate peri-injury complications (ref: absence of or mild complications; HR 6.0 [95% CI 2.3 to 16.0]; p < 0.001), severe peri-injury complications (ref: absence of or mild complications; HR 30.0 [95% CI 11.5 to 78.3]; p < 0.001), ASIA Grade A (ref: ASIA Grade D; HR 2.8 [95% CI 1.1 to 7.0]; p = 0.03), anterior approach (ref: nonsurgical treatment; HR 0.5 [95% CI 0.2 to 1.0]; p = 0.04), posterior approach (ref: nonsurgical treatment; HR 0.4 [95% CI 0.2 to 0.8]; p = 0.006), and combined anterior and posterior approach (ref: nonsurgical treatment; HR 0.4 [95% CI 0.2 to 0.9]; p = 0.02) were associated with survival. Based on these factors, a nomogram was developed to predict the survival of patients with ASCF-NI after treatment. Tests revealed that the developed nomogram had good performance (C statistic of 0.91).

CONCLUSION

The nomogram developed in this study will allow us to classify patients with different mortality risk levels into groups. This, coupled with the factors we identified, was independently associated with survival, and can be used to guide more appropriate treatment and care strategies for patients with ASCF-NI.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Perioperative risk stratification of spine trauma patients with ankylosing spinal disorders: a comparison of 3 quantitative indices

OBJECTIVE

Patients with ankylosing spinal disorders (ASDs), including ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH), have been shown to experience significantly increased rates of postoperative complications. Despite this, very few risk stratification tools have been validated for this population. As such, the purpose of this study was to identify predictors of adverse events and mortality in ASD patients undergoing surgery for 3-column fractures.

METHODS

All adult patients with a documented history of AS or DISH who underwent surgery for a traumatic 3-column fracture between 2000 and 2020 were identified. Perioperative variables, including comorbidities, time to diagnosis, and number of fused segments, were collected. Three instruments, including the Charlson Comorbidity Index (CCI), modified frailty index (mFI), and Injury Severity Score (ISS), were computed for each patient. The primary outcomes of interest included 1-year mortality, as well as postoperative complications.

RESULTS

A total of 108 patients were included, with a mean ± SD age of 73 ± 11 years. Of these, 41 (38%) experienced at least 1 postoperative complication and 22 (20.4%) died within 12 months after surgery. When the authors controlled for potential known confounders, the CCI score was significantly associated with postoperative adverse events (OR 1.20, 95% CI 1.00-1.42, p = 0.045) and trended toward significance for mortality (OR 1.19, 95% CI 0.97-1.45, p = 0.098). In contrast, mFI score and ISS were not significantly predictive of either outcome.

CONCLUSIONS

Complications in spine trauma patients with ASD may be driven by comorbidity burden rather than operative or injury-related factors. The CCI may be a valuable tool for the evaluation of this unique population.

Instantaneous death risk, conditional survival and optimal surgery timing in cervical fracture patients with ankylosing spondylitis: A national multicentre retrospective study

Background

The mortality rate in patients with ankylosing spondylitis (AS) and cervical fracture is relatively high.

Objectives

This study aimed to investigate the instantaneous death risk and conditional survival (CS) in patients with AS and cervical fracture. We also studied the relationship between surgical timing and the incidence of complications.

Methods

This national multicentre retrospective study included 459 patients with AS and cervical fractures between 2003 and 2019. The hazard function was used to determine the risk of instantaneous death. The five-year CS was calculated to show the dynamic changes in prognosis.

Results

The instantaneous death risk was relatively high in the first 6 months and gradually decreased over time in patients with AS and cervical fracture. For patients who did not undergo surgery, the instantaneous risk of death was relatively high in the first 15 months and gradually decreased over time. For patients with American Spinal Injury Association impairment scale (ASIA) A and B, the 5-year CS was 55.3% at baseline, and improved steadily to 88.4% at 2 years. Odds ratios (ORs) for pneumonia, electrolyte disturbance, respiratory insufficiency, and phlebothrombosis decreased as the surgery timing increased.

Conclusion

Deaths occurred mainly in the first 6 months after injury and gradually decreased over time. Our study highlights the need for continued surveillance and care in patients with AS with cervical fractures and provides useful survival estimates for both surgeons and patients. We also observed that early surgery can significantly increase functional recovery, and decrease the incidence of complications and rehospitalisation.

Factors Associated With Major Complications and Mortality During Hospitalization in Patients With Ankylosing Spondylitis Undergoing Surgical Management for a Spine Fracture

STUDY DESIGN

Retrospective study.

OBJECTIVES

To analyze factors associated with major complications (MC) in patients with ankylosing spondylitis (AS) undergoing surgical management for a spine fracture.

METHODS

Included were all persons with spine fractures and AS in a teriary health care center between 2003 and 2019. Clinical data and MC were characterized with descriptive characteristics. Multivariable analyses were used to find factors associated with MC.

RESULTS

In total, 174 traumatic fracture incidents in 166 patients with AS were included, with a mean patient age of 70.7 ± 13.1 years. The main reason for spine fracture was minor trauma (79.9%). Spinal cord injuries (SCI) were described in 36.7% of cases. The majority of patients (54.6%) showed more than one fracture of the spine, with cervical fractures being the most common (50.5%). Overall, the incidences of surgical site infection, implant failure, nosocomial pneumonia (NP), and mortality were 17.2%, 9.2%, 31%, and 14.9%, respectively. ICU stay > 48 hours was associated with MC (including death). Posterior approach for spondylodesis, ICU stay > 48 hours and cervical SCI were related to MC (excluding death). Age > 70 years, NP and Charlson comorbidity index > 5 points were associated with in-hospital mortality.

CONCLUSIONS

Patients with AS and surgical treatment of spine fractures are at high risk for MC. Therefore, our results might give physicians better insight into the incidence and sequelae of major complications and therefore might improve patient and family expectations.

Impact of age on mortality and complications in patients with Ankylosing Spondylitis spine fractures

OBJECTIVE

The aim of this retrospective cohort study was to study the impact of age on in-hospital complications and mortality following surgery for Ankylosing Spondylitis (AS) associated spine fractures.

METHODS

We extracted data from the Nationwide Inpatient Sample (NIS) database (1998-2018) using ICD-9/10 codes. Patients with a primary diagnosis of AS associated spine fractures who underwent fusion surgery were included. Complications and in-hospital mortality were analyzed.

RESULTS

A total cohort of 8526 patients was identified. Overall, the median age of the cohort was 69 years. AS associated fractures were equally distributed among cervical and thoracolumbar regions. Overall, complications were noted in 48% of patients and pulmonary complications were the most common (32%) followed by renal (13%) and infection (12%). Complications were seen in 57.3% of patients ≥ 70 years of age compared to 38.4% of patients < 70 years of age (p < .0001). Also, 9.9 % of patients ≥ 70 years of age had in-hospital mortality compared to 3.1 % of patients < 70 years of age (p < .0001). Based on surgical approaches, elderly patients (≥70 years) who underwent anterior, posterior, and anterior + posterior approaches had 19.8%, 7.4% and 16.4% in-hospital mortality compared to 5.3%, 2.2% and 7.4% respectively for patients < 70 years.

CONCLUSIONS

Elderly patients (≥70 years of age) were 3.2 times more likely to have in-hospital mortality and higher complications compared to younger patients (57% vs. 38%). Cervical compared to thoracolumbar fractures and anterior compared to posterior surgical approaches were associated with higher complications and in-hospital mortality.

Single versus dual operative spine fractures in ankylosing spondylitis

OBJECTIVE

Ankylosing spondylitis, the most common spondyloarthritis, fuses individual spinal vertebrae into long segments. The unique biomechanics of the ankylosed spine places patients at unusually high risk for unstable fractures secondary to low-impact mechanisms. These injuries are unique within the spine trauma population and necessitate thoughtful management. Therefore, the authors aimed to present a richly annotated data set of operative AS spine fractures with a significant portion of patients with simultaneous dual noncontiguous fractures.

METHODS

Patients with ankylosing spondylitis with acute fractures who received operative management between 2012 and 2020 were reviewed. Demographic, admission, surgical, and outcome parameters were retrospectively collected and reviewed.

RESULTS

In total, 29 patients were identified across 30 different admissions. At admission, the mean age was 71.7 ± 11.8 years. The mechanism of injury in 77% of the admissions was a ground-level fall; 30% also presented with polytrauma. Of admissions, 50% were patient transfers from outside hospitals, whereas the other half presented primarily to our emergency departments. Fifty percent of patients sustained a spinal cord injury, and 35 operative fractures were identified and treated in 32 surgeries. The majority of fractures clustered around the cervicothoracic (C4-T1, 48.6%) and thoracolumbar (T8-L3, 37.11%) junctions. Five patients (17.2%) had simultaneous dual noncontiguous operative fractures; these patients were more likely to have presented with a higher-energy mechanism of injury such as a bicycle or motor vehicle accident compared with patients with a single operative fracture (60% vs 8%, p = 0.024). On preoperative MRI, 56.3% of the fractures had epidural hematomas (EDHs); 25% were compressive of the underlying neural elements, which dictated the number of laminectomy levels performed (no EDH, 2.1 ± 2.36; noncompressive EDH, 2.1 ± 1.85; and compressive EDH, 7.4 ± 4 [p = 0.003]). The mean difference in instrumented levels was 8.7 ± 2.6 with a mean estimated blood loss (EBL) of 1183 ± 1779.5 mL. Patients on a regimen of antiplatelet therapy had a significantly higher EBL (2635.7 mL vs 759.4 mL, p = 0.015). Overall, patients had a mean hospital length of stay of 15.2 ± 18.5 days; 5 patients died during the same admission or after transfer to an outside hospital. Nine of 29 patients (31%) had died by the last follow-up (the mean follow-up was 596.3 ± 878.9 days).

CONCLUSIONS

Patients with AS who have been found to have unstable spine fractures warrant a thorough diagnostic evaluation to identify secondary fractures as well as compressive EDHs. These patients experienced prolonged inpatient hospitalizations with significant morbidity and mortality.

Post-traumatic spinal hematoma in ankylosing spondylitis

PURPOSE

The purpose of this study is to examine the incidence, location, and magnetic resonance imaging (MRI) features of spinal epidural hematoma (SEH) and spinal subdural hematoma (SSH) in post-traumatic ankylosing spondylitis (AS) patients.

METHODS

A total of 2256 consecutive referrals for urgent and emergency MRI scans of the spine over a period of eight years and nine months were manually reviewed for any mentions indicating axial ankylosis and post-traumatic spinal hematoma. We found 164 patients with ankylosed spines complicated by spinal fracture, of whom 32 had AS. Of the 132 excluded patients, 80 had diffuse idiopathic skeletal hyperostosis (DISH). The primary outcome was the presence of spinal hematoma, and the secondary outcome was spinal canal narrowing and spinal cord impingement. Two musculoskeletal radiologists and one fellow in musculoskeletal radiology reviewed the images for the presence of spinal hematoma and related signal characteristics, blinded to one another and initial reports.

RESULTS

Of 28 post-traumatic AS patients, 19 had SEHs and five had spinal SSHs. There was a statistically significant difference between Frankel grades before and after surgery in respect of neurological improvement (p = 0.008). Patients who had radiologically proven spinal cord impingement showed more severe neurological deficits (p = 0.012). Hematomas with T1 heterogeneity showed a significantly increased delay (p = 0.047) between injury and imaging, while other signal characteristics were only approximate.

CONCLUSIONS

Both SEH and SSH are common complications in post-traumatic AS patients. Patients benefit from surgery, but the relevance of spinal hematoma as a separate factor causing neurological deficit remains unclear.

Predictor of Surgical Outcomes in Ankylosing Spondylitis Cervical Spinal Fracture: An At Least 2 Years Follow-Up Retrospective Study

STUDY DESIGN

Retrospective study.

OBJECTIVE

A retrospective study was conducted to clarify the prognostic factors of postoperative for cervical spine fractures patients with ankylosing spondylitis (AS).

SUMMARY OF BACKGROUND DATA

Now the high probability of cervical fractures in patients with AS is unanimously recognized. Fractures mostly occur in the lower cervical spine and two-thirds of patients are accompanied by spinal cord injury. But there are few studies on treatment of AS patients with cervical fracture and it is unclear whether the surgical method, timing of surgery, basic treatment of AS, and different doses of steroids therapy have an impact on the prognosis. Thus, this study aims to evaluate the impact of perioperative factors on the prognosis of traumatic cervical fractures in surgical patients with AS.

METHODS

Preoperative and postoperative spinal cord function were assessed according to the Japanese Orthopaedic Association (JOA) Scores and Improvement rate were calculated. The neck pain severity were rated using a visual analogue scale (VAS) score. The t test and v2-test were used for comparison of clinical data between the preoperative and postoperative groups. Logistic univariate and multivariate regression analysis were used to obtain adjusted odds ratios. Pearson correlation coefficients were used to evaluate the relationship between variables.

RESULTS

The degree of fracture displacement in cervical spine fractures patients with AS was most common at the neck-chest junction (26.1%). Patients with degree of cervical fracture displacement less than 50% had significantly improved JOA scores after surgery (P = 0). The incidence of spinal cord injury (SCI) due to fracture was high (52.2%). Patients with combined anterior and posterior is helpful for neurological recovery (P = 0.01). Basic AS treating before injury would be benefit for neurological improvement (P = 0).

CONCLUSION

Basic AS treatment, SCI, and surgical methods are independent factors that affect the prognosis of cervical spine fractures patients with AS. It is controversial to perform surgery and preoperative steroid application as soon as possible.

LEVEL OF EVIDENCE

3.

Identifying Patients With Axial Spondyloarthritis in Large Datasets: Expanding Possibilities for Observational Research

OBJECTIVE

Observational research of axial spondyloarthritis (axSpA) is limited by a lack of methods for identifying diverse axSpA phenotypes in large datasets. Algorithms were previously designed to identify a broad spectrum of patients with axSpA, including patients not identifiable with diagnosis codes. The study objective was to estimate the performance of axSpA identification methods in the general Veterans Affairs (VA) population.

METHODS

A patient sample with known axSpA status (n = 300) was established with chart review. For feasibility, this sample was enriched with veterans with axSpA risk factors. Algorithm performance outcomes included sensitivities, positive predictive values (PPV), and F1 scores (an overall performance metric combining sensitivity and PPV). Performance was estimated with unweighted outcomes for the axSpA-enriched sample and inverse probability weighted (IPW) outcomes for the general VA population. These outcomes were also assessed for traditional identification methods using diagnosis codes for the ankylosing spondylitis (AS) subtype of axSpA.

RESULTS

The mean age was 54.7 and 92% were male. Unweighted F1 scores (0.59-0.74) were higher than IPW F1 scores (0.48-0.65). The full algorithm had the best overall performance (F1_IPW 0.65). The Early Algorithm was the most inclusive (sensitivity_IPW 0.90, PPV_IPW 0.38). The traditional method using ≥ 2 AS diagnosis codes from rheumatology had the highest PPV (PPV_IPW 0.84, sensitivity_IPW 0.34).

CONCLUSION

The axSpA identification methods demonstrated a range of performance attributes in the general VA population that may be appropriate for various types of studies. The novel identification algorithms may expand the scope of research by enabling identification of more diverse axSpA populations.

An Analysis of Patient and Fracture Characteristics and Clinical Outcomes in Patients With Hyperostotic Spine Fractures

STUDY DESIGN

Retrospective study.

OBJECTIVE

To evaluate outcomes and complications following operative and nonoperative management of hyperostotic spine fractures.

METHODS

Patients presenting between 2008 and 2017 to a single level 1 trauma center with hyperostotic spine fractures had their information and fracture characteristics reviewed. Bivariate analyses were conducted to compare patients across a number of characteristics and outcomes. Multivariate logistic regression models for complication and mortality were done in a stepwise fashion.

RESULTS

Sixty-five ankylosing spondylitis (AS) or diffuse idiopathic skeletal hyperostosis (DISH) patients with a spine fracture met our inclusion criteria. DISH was slightly more prevalent (55% vs 45%). Overall delayed diagnosis, reoperation, mortality (at 1 year), and complication rates were high at 32%, 13%, 23%, and 57%, respectively. In multivariate logistic regression models, patients undergoing operative management had significantly increased odds of having a complication (odds ratio [OR] = 23.03, 95% confidence interval [CI] = 2.24-236.45, P = .008), while increasing age was associated with increased odds of death (OR = 1.18, 95% CI = 1.06-1.31, P = .003).

CONCLUSIONS

Patients with AS or DISH who fracture their spine are at high risk of complication and death. However, neither operative nor nonoperative treatment increases the odds of mortality. This study helps add to a growing, but still limited, body of literature on the characteristics of patients with spine fractures in the setting of AS or DISH.

The Risk and Consequences of Vertebral Fracture in Patients with Ankylosing Spondylitis: A Population-based Data Linkage Study

OBJECTIVE

To compare the long-term prevalence, incidence, and outcomes of vertebral fracture (VF) between ankylosing spondylitis (AS) patients and matched controls, including the role of extraarticular manifestations (EAM) and osteoporosis.

METHODS

This was a statewide observational study using linked health data for 2321 patients with AS and 22,976 controls presenting to hospital from 1980 to 2015. Data were analyzed using incidence rates (per 1000 person-yrs) and ratios (IRR), multivariable Cox proportional hazards regression, and Kaplan-Meier survival curves.

RESULTS

Over a median 13.92 (interquartile range 7.58-21.67) years of follow-up, patients with AS had a greater VF prevalence and greater incidence of developing a new VF compared to controls (9.3% vs 2.5%, 6.8% vs 1.9%, respectively, all P < 0.001). Patients with AS had an increased risk of developing a VF after adjustments for age, sex, and osteoporosis (HR 2.55, 95% CI 2.11-3.09) compared to controls; this risk remained throughout the study period. Patients with AS were 5 years younger at time of first VF (P = 0.008) and had a greater likelihood of a recurrent VF (IRR 4.64; 95% CI 4.54-4.75) compared to respective controls. Mortality overall was comparable between patients with AS and controls after adjustment for age, sex, osteoporosis, and VF status (HR 0.90; 95% CI 0.80-1.01).

CONCLUSION

The significantly increased risk of VF in patients with AS has not altered following the introduction of tumor necrosis factor inhibitor treatment. Although patients with AS experience a first VF at a younger age than controls, this does not lead to an increased risk of death.

Cauda Equina Syndrome in Ankylosing Spondylitis: Challenges in Diagnosis, Management, and Pathogenesis

OBJECTIVE

Cauda equina syndrome (CES) is a rare neurologic complication of longstanding ankylosing spondylitis (AS). It is unclear what causes CES, and no proven or effective therapy has been reported to date. We have encountered 6 patients with longstanding AS diagnosed with CES. We set about to study their features, review the literature, and generate hypotheses regarding pathophysiology, as well as to speculate on the possibilities of early recognition and prevention.

METHODS

We obtained permission from 6 patients with longstanding AS and CES to access their medical records and imaging studies for research purposes related to this paper. We collected and reviewed each patient's medical history, imaging studies, disease duration, past therapies especially those that relate to AS, laboratory data, as well as any treatment they received for CES and followup results of each case to the present time.

RESULTS

The 6 cases of CES with AS have remarkable similarity to each other in that several decades of the disease had passed before neurologic symptoms and later signs appeared. All cases have fused spines and facet joints without spinal fractures, spinal stenosis, or disc herniation.

CONCLUSION

CES is a rare yet debilitating neurologic complication of longstanding AS. The pathophysiology and treatments are far from clear. We postulate that chronic enthesitis of the vertebral column initiates the process that results in dural stiffening and formation of ectasias, causing downstream nerve root damage.

Identification of Axial Spondyloarthritis Patients in a Large Dataset: The Development and Validation of Novel Methods

OBJECTIVE

Observational axial spondyloarthritis (axSpA) research in large datasets has been limited by a lack of adequate methods for identifying patients with axSpA, because there are no billing codes in the United States for most subtypes of axSpA. The objective of this study was to develop methods to accurately identify patients with axSpA in a large dataset.

METHODS

The study population included 600 chart-reviewed veterans, with and without axSpA, in the Veterans Health Administration between January 1, 2005, and June 30, 2015. AxSpA identification algorithms were developed with variables anticipated by clinical experts to be predictive of an axSpA diagnosis [demographics, billing codes, healthcare use, medications, laboratory results, and natural language processing (NLP) for key SpA features]. Random Forest and 5-fold cross validation were used for algorithm development and testing in the training subset (n = 451). The algorithms were additionally tested in an independent testing subset (n = 149).

RESULTS

Three algorithms were developed: Full algorithm, High Feasibility algorithm, and Spond NLP algorithm. In the testing subset, the areas under the curve with the receiver-operating characteristic analysis were 0.96, 0.94, and 0.86, for the Full algorithm, High Feasibility algorithm, and Spond NLP algorithm, respectively. Algorithm sensitivities ranged from 85.0% to 95.0%, specificities from 78.0% to 93.6%, and accuracies from 82.6% to 91.3%.

CONCLUSION

Novel axSpA identification algorithms performed well in classifying patients with axSpA. These algorithms offer a range of performance and feasibility attributes that may be appropriate for a broad array of axSpA studies. Additional research is required to validate the algorithms in other cohorts.

Association of Congestive Heart Failure and Death with Ankylosing Spondylitis : A Nationwide Longitudinal Cohort Study in Korea

Objective

We attempted to discover that Ankylosing spondylitis (AS) has a comprehensive relationship with congestive heart failure and death.

Methods

We used a nationwide database managed by the Korean National Health Insurance Service from 2010 to 2014. Twelve thousand nine hundred eighty-eight patients with a diagnosis of AS and 64940 age- and sex- stratified matching subjects without AS were enrolled in the AS and control groups. Incidence probabilities of 6 years congestive heart failure and death in each group were calculated. The Cox proportional hazard regression analysis was used to estimate the hazard ratio. We divided the AS and control groups into subgroups according to sex, age, income, and comorbidities.

Results

During the follow-up period, 102 patients (0.79%) in the AS group and 201 patients (0.32%) in the control group developed congestive heart failure (p<0.0001). In addition, 211 (1.62%) subjects in the AS group died during the follow-up period compared to 639 (0.98%) subjects in the control group (p<0.0001). The adjusted hazard ratio of congestive heart failure and death in the AS group was 2.28 (95% confidence interval [CI], 1.80–2.89) and 1.66 (95% CI, 1.42–1.95), respectively. The hazard ratios of congestive heart failure and death were significantly increased in all of the subgroups.

Conclusion

The incidence rates of congestive heart failure and death were increased in AS patients.

Cohort identification of axial spondyloarthritis in a large healthcare dataset: current and future methods

BACKGROUND

Big data research is important for studying uncommon diseases in real-world settings. Most big data studies in axial spondyloarthritis (axSpA) have been limited to populations identified with billing codes for ankylosing spondylitis (AS). axSpA is a more inclusive concept, and reliance on AS codes does not produce a comprehensive axSpA study population. The first objective was to describe our process for establishing an appropriate sample of patients with and without axSpA for developing accurate axSpA identification methods. The second objective was to determine the classification performance of AS billing codes against the chart-reviewed axSpA reference standard.

METHODS

Veteran Health Affairs clinical and administrative data, between January 2005 and June 2015, were used to randomly select patients with clinical phenotypes that represented high, moderate, and low likelihoods of an axSpA diagnosis. With chart review, the sampled patients were classified as Yes axSpA, No axSpA or Uncertain axSpA, and these classification assignments were used as the reference standard for determining the positive predictive value (PPV) and sensitivity of AS ICD-9 codes for axSpA.

RESULTS

Six hundred patients were classified as Yes axSpA (26.8%), No axSpA (68.3%), or Uncertain axSpA (4.8%). The PPV and sensitivity of an AS ICD-9 code for axSpA were 83.3% and 57.3%, respectively.

CONCLUSIONS

Standard methods of identifying axSpA patients in a large dataset lacked sensitivity. An appropriate sample of patients with and without axSpA was established and characterized for developing novel axSpA identification methods that are anticipated to enable previously impractical big data research.

Patterns of comorbidity and disease characteristics among patients with ankylosing spondylitis-a cross-sectional study

The knowledge of the development of comorbidities in patients with ankylosing spondylitis (AS) is limited. The aim of this study was to analyse associations between AS disease characteristics and comorbidity and to evaluate patterns of comorbidities in patients with AS. Patients with AS, fulfilling the modified New York Criteria, were identified (n = 346, mean age 56 ± 15 years, 75% men, 99% HLA B27 positive). Through a review of the patient records, data on disease activity parameters, laboratory results, disease manifestations, and diagnoses of any clinically significant comorbidity was obtained. Four categories of comorbidities of interest were identified: A. arrhythmias, conduction disorders, and valvular heart disease; B. atherosclerosis and atherosclerotic CVD; C. spinal and non-spinal fractures; and D. obstructive sleep apnoea syndrome. Associations between AS disease characteristics and comorbidities in categories were assessed in logistic regression models. Differences in proportions of comorbidities was analysed using two-sided chi-square. Age was associated with all four categories of comorbidities, and male sex with arrhythmias, conduction disorders, valvular heart disease, and obstructive sleep apnoea syndrome. Early disease onset and long disease duration, respectively, were associated with arrhythmias, conduction disorders, and valvular heart disease. Obstructive sleep apnoea syndrome was associated with features of the metabolic syndrome. Patients with atherosclerotic cardiovascular disease had an increased risk of most other comorbidities, similar to, but more pronounced than patients with arrhythmias, conduction disorders and valvular heart disease. Comorbid conditions motivate clinical awareness among patients with AS. Longitudinal studies are needed to establish preventive measures.

One-stage surgical treatment of cervical spine fracture-dislocation in patients with ankylosing spondylitis via the combined anterior-posterior approach

The aim of the article is to investigate the efficacy and safety of 1-stage surgical therapy via combined anterior-posterior approach on cervical spine fracture in patients with ankylosing spondylitis (AS).We retrospectively analyzed profiles of 12 AS patients with severe fracture-dislocation of cervical spine received 1-stage combined anterior-posterior surgery in our hospital from October, 2013, to October, 2015, including clinical characteristics, follow-up data, and imaging records. We compared the parameters before and after surgery on the basis of neurological function, bone fusion, Cobb angles of operation segment, Barthel index (BI) score, and incidence rate of complications.A total of 12 patients received 1-stage surgery via combined anterior-posterior approach within 3 days after injury. No severe complications and death occurred. All patients received the successfully anatomical reduction of fracture-dislocation, in which 9 achieved function restoration. The latest follow-up showed the neurological function status of patients was improved. The Cobb angles of operation segments were recovered; the rate of bone fusion was 66.7% at 3 months and 100% at 6 months post-operation. The BI score was improved, 4 cases of moderate dependence and 8 of slight dependence at the latest follow-up compared to 10 of severe dependence and 2 of moderate dependence preoperation. In no cases did severe complications from implanted instrumentation occur.It was high efficacy and safety that the surgical therapy was performed on cervical fracture-dislocation in AS patients by the 1-stage combined anterior-posterior approach. The key of the surgery is the robust stabilization and full decompression of fracture spine at early stage. In addition, if spinal anatomical reduction of fracture segments is difficult to be achieved, the functional restoration should be adopted during the surgery.