A recent study has reported significant improvements in patients’ frailty status at one-year after surgery, as shown by the cervical deformity frailty index (CD-FI). The data, including a discussion about the efficacy of the index tool itself, were presented by Peter G Passias, NYU Langone Health, New York, USA, at the North American Spine Society annual meeting (NASS; 26–29 September, 2018, Los Angeles, USA).
Passias acknowledged that cervical deformity can be a severely debilitating condition, while it also poses a significant challenge for surgeons with regards to its pathology. Furthermore, the deformity encompasses a wide range of aetiologies, including spondylosis, inflammatory arthropathy, trauma, and infection, as well as congenital and neuromuscular pathologies.
Passias described the concept of frailty; a term derived from the geriatric literature. However, he noted that instead of acknowledging a patient’s chronological age, it attempts to encompass the pathological age, i.e. how deconditioned or frail a patient is.
The cervical deformity frailty index (CD-FI) was recently devised by Miller and colleagues, which correlated increased patient frailty with longer hospital stays, higher complication rates and increased risk of non-home discharge. However, Peters suggested that the limitations of the CD-FI should not be overlooked. The index requires 40 health variables (from a patients demographic and surgical information) to calculate a score, yet it is unknown which of the variables have the greatest potential for change or are the primary drivers of post-operative change in frailty.
Therefore, Passias and colleagues aimed to investigate the component variables of the CD-FI in order to determine the impact of corrective surgery on the index, while also identifying which component variables of CD-FI are modifiable, as opposed to those that are non-modifiable.
A retrospective review of a prospective multicentre cervical deformity database, at multiple sites through the USA, was carried out. The inclusion criteria were radiographic; patients had to have a certain amount of kyphosis, for example a C2–7 sagittal or coronal Cobb angle of ≥10°, a C2–7 sagittal vertical axis ≥4cm or a chin-brow vertical angle of≥25°. Additionally, all patients were 18 years or older, and their CD-FI was examined at baseline and after one year.
Passias noted that 40 variables are used to calculate the frailty index, including past medical history questions (such as a history of congestive heart failure, stroke, or high blood pressure), as well as and health-related quality of life questions (HRQL). The latter are taken from various forms, such as: the Neck Disability Index (NDI), the modified Japanese Orthopaedic Association scale (mJOA), the Quality of Life in Swallowing Disorders questionnaire (SWAL-QOL) and other similar instruments.
Frailty as a measure itself was assessed using the cervical deformity frailty index (CD-FI), scored on a scale between zero and one. Patients were subsequently stratified by CD-FI scores, which resulted in three groups dependent on the patient’s level of frailty. A score of below 0.3 was defined as “not frail”, with patients falling between 0.3–0.5 classified as “frail” and those above 0.5 “severely frail”. In total, the patient population included 138 cervical deformity patients (62% female; mean age: 61 years; mean BMI: 29.3). The Charlson Comorbidity Index indicated an average score of 0.92 for the patient cohort.
Regarding the change in frailty following the surgical intervention and CD-FI variables, Passias reported that patients significantly improved, shown by the change in the baseline frailty scores from 0.44 to 0.27 after one-year following the surgical intervention (p<0.001); a finding which Passias stressed was very important.
In terms of improvements in radiographic and frailty component variables at one year, significant improvements—shown through statistically significant correlations extracted through the questionnaire—were observed in the following measurements: the ability to read (p=0.045) and whether or not patients felt exhausted (shown through SWAL 9E; p<0.001).
Regarding the linear regression analysis, Passias and colleagues found a significant improvement in patients’ EQD5 VAS (EuroQoL, 5 Dimension Visual Analogue Scale) score and also in their anxiety. The authors noted that improvements in feeling exhausted, as well as achieving the lowest Ames deformity classification (indicating successful surgery) were the greatest predictors of post-operative frailty change.
Summarising the results, Passias concluded that the changes in the CDFI at one-year post-surgery indicated that average frailty decreased from 0.44 (a “severely frail” status) to 0.25 (“frail” status). Additionally, out of the 40 variables that were included in the index, half of them (20/40) improved at one year; with a third (13/40) improving significantly. The majority of the drivers of frailty were related to the outcome measures, such as: reading without pain, feeling exhausted, and the ability to drive—which all showed the greatest correlation with change in frailty. Therefore, he stated that improvements in a patient’s ability to not feel exhausted or weak, as well as overall balance and sagittal alignment, are all highly correlated with improved postoperative frailty status. Passias said that it became clear that surgery has the ability to improve all of these measures, as it resulted in patients becoming more active, while enjoying a better quality of life.