Comorbidity Burden Associated With Poor Outcomes in Atlantoaxial Fusion

Peer Reviewed

atlantoaxial, axis, atlas, spineAge and comorbidity burden are associated with higher rates of postsurgical mortality, longer lengths of in-hospital stay, higher hospital charges and a higher probability of being discharged to an outside care facility after atlantoaxial fusion, according to a large, new retrospective study.

Joseph Tanenbaum and colleagues from the Center for Spine Health at the Cleveland Clinic and School of Medicine at Case Western Reserve University reported their findings in a recent issue of The Spine Journal. The authors commented on the need for this type of large study.

“Limitations caused by sample size and sampling bias render prior studies unable to accurately determine predictors of outcome following atlantoaxial fusion because they cannot control for confounders such as socioeconomic status, race, and patient clustering.”

The editors of The Spine Journal note that “These findings provide useful information that may be used for preoperative counseling for patients.” However, they also mention an important caveat. “Given the number of years included in this analysis, which span a time period of fairly rapid evolution in spinal instrumentation and surgical techniques, it is unclear that results are entirely relevant to patients with these issues who are receiving surgery today.”

Results Taken From NIS Database
Data from 8,189 patients in the Nationwide Inpatient Sample (NIS) from 1998-2011 were included. The average age of the patients was 60.2 years, with 52.3% being male. The overall in-hospital mortality rate was 2.7%, and the total median inflation-adjusted charge per hospitalization was $73,561, with 48.9% being discharged to home. Medicare (47.2%) and private health insurers (35.6%) were the main payers, and hypertension (43.2%), electrolyte disorder (17.3%) and diabetes (11.1%) were the main comorbidities. Closed C2 fracture was the most common primary diagnosis at 18.9%, followed by non-union fracture (9.4%), cervical spondylosis with myelopathy (8.1%), and closed C1 fracture (7%).

Predictors of In-Hospital Mortality
The highest predictor of risk for mortality was age 80 and older (OR: 4.5), followed by age 70-79 (OR: 3.8), coagulopathy (OR: 2.9), metastatic cancer (OR: 2.5), coronary heart failure (CHF) (OR: 2.4), and age 60-69 (OR: 2.2). All odds ratios were P<.05.

Predictors of Length of Stay and Hospital Charges
Pathological weight loss increased the mean length of stay (LOS) the most at 77% and increased the mean hospital charges (HC) the most at 84%. Paralysis came in second in influencing LOS and HC at 74% and 59% respectively.

Electrolyte disorder increased LOS by 61%, while metastatic cancer increased LOS and HC by 47% and 38% respectively. Blood loss anemia increased LOS and HC by 44% and 39% while weekend admission increased LOS and HC by 39% and 35% respectively. CHF increased LOS 30%, and coagulopathy increased LOS 26% and HC 48%.

Elective admission decreased the mean LOS and HC the most at 47% and 19%, followed by the procedure being performed at a teaching hospital at 22% and 14% respectively.

Predictors of Discharge to the Patients Home
Elective admission was associated with the highest odds of being discharged to home rather than another care facility (OR: 2.39). This was followed by self-pay (OR: 2.02), other pay (OR: 1.88) and private pay and southern hospital region (OR: 1.74). The lowest predictors of being discharged to home were age 80 and older (OR: .12), paralysis (OR: .17), age 70-79 (OR: .25) and pathological weight loss (OR: .28).

Commonalities Found and Questions
Pathological weight loss and paralysis were the most commonly observed comorbidities that contributed to poor patient outcomes followed by age 80 and older. Elective admission and procedure being performed at a teaching hospital most frequently contributed to better patient outcomes.

“Depression was associated with reduced odds of in-hospital mortality in our study,” the authors stated. There is no clear understanding of why this occurs, only hypotheses. However, “If true, this hypothesis potentially renders administrative databases such as the NIS suboptimal for studying the effects of non-life threatening conditions on postoperative outcomes,” the authors added.

Better Patient Outcomes
By determining predictors of atlantoaxial fusion outcomes, physicians and patients can benefit. “Our findings can improve patient selection and preoperative counseling by serving as the starting point in the construction of clinical decision tools that can calculate and visually depict risk of in-hospital mortality or non-routine discharge following atlantoaxial fusion,” the authors explained.

Hospitals concerned with quality of care issues also benefit by being able to implement targeted risk reduction programs, which lead to “improved outcomes while controlling charges associated with atlantoaxial fusion” the authors concluded.

Peer Discussion

Vincent Traynelis, MD
Professor of Neurosurgery
Rush University
Chicago, IL

This study focuses on hospital charges, hospital length of stay, hospital mortality, and disposition at discharge. These are important items and it is not surprising that each is moved in a negative direction by comorbidities. The data have flaws, but for the most part, are probably accurate. While this information may not alter a recommendation for surgery, it may be useful for the patient to know when discussing a C1-C2 fusion.

Updated on: 09/07/16
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