Abstract
Purpose:
Early surgery for older adults with hip fracture has been shown to improve outcomes. We aim to study the factors contributing to delay in surgery (defined as surgery performed more than 48 h after admission) and its associated outcomes in a tertiary hospital in Singapore with an integrated hip fracture program.
Methods:
This is a prospective cohort study of hip fracture patients aged more than 60 years over 1 year. We collected data on demographics, premorbid mobility and functional status, time to surgery, postoperative complications, and inhospital mortality. Mortality data and functional performance were reviewed at 1 year.
Results:
High American Society of Anaesthesiologists score independently predicted delay in surgery (odd ratio (OR) = 9.52, 95% confidence interval (CI): 1.69–53.68). Delayed surgery was significantly associated with longer length of stay (median 12.8 days with interquartile range (IQR) 9.7–17.6 days vs. 8.35 days with IQR 5.9–10.9 days, p < 0.01). Surgery within 48 h significantly reduced functional decline (Modified Barthel Index change −3.89 ± 17.23 vs. −9.29 ± 20.30, p = 0.01) and 1-year mortality (3.5% vs. 9.3%, p = 0.03). Surgical delay was an independent risk factor for early postoperative complications (OR = 3.21, 95% CI: 1.21–8.49), and patients were significantly less likely to return to premorbid mobility at 1 year (OR = 0.62, 95% CI: 0.39–0.97).
Conclusions:
Delayed hip fracture surgery in older adults is associated with worse short- and long-term outcomes, including early postoperative complications and poorer functional recovery.
Introduction
Hip fractures continue to be a major public health concern. With the aging population, the number of hip fractures is projected to increase yearly from 1.66 million in 1990 to 6.26 million in 2050. 1 Hip fractures are associated with increased risk of death, with mortality rate ranging from 22% to 51% in the first year post-injury. Patients who had hip fractures are also more likely to have increased dependence on walking aids, increased institutionalization and more residual pain. 2 Surgery is the ideal treatment, allowing early mobilization, better pain reduction, and potential to return to premorbid function. However, adverse outcomes remain high despite surgery, with mortality rates up to 39.5% in the first year post-injury. 3
Our institution is one of the busiest tertiary hospitals in Singapore due to its geographical location. The hospital admits about 500 cases of hip fracture per year. A hip fracture program was initiated in our institution in 1997 to standardize the care for hip fracture patients. The orthogeriatric service started as a part of collaborative process to improve the care of elderly who were admitted for hip fractures. Patient education and discharge planning were facilitated by skilled and experienced nurses called care managers who assisted in identifying and referral of suitable patients to rehabilitation facilities. Integration with post-discharge facilities was formed in 2011, resulting in a 5-year program to provide a seamless coordination of care beginning from admission in acute hospital throughout the perioperative period until discharge into rehabilitation facility and various community rehabilitation services. 4 One of the key targets was to expedite time to surgery within 48 h of admission. Upon diagnosis of hip fracture in the emergency department, workflow processes would be activated to allow early identification of medical issues that can delay surgery. The development of fitness for operation criteria allowed patients with minor clinical abnormalities to be listed for surgery while undergoing correction, thereby reducing the potential surgical delay. While the exact definition of early surgery is debatable, the current consensus is to perform surgery within 48 h of admission, and this is the target used in our institution. 5,6
The primary objective of this study was to identify patient-related factors that contribute to delay in hip fracture surgery among our cohort of older adults during the first year of our integrated hip fracture program. Our secondary objective was to look at the impact of surgical delay on the following outcomes, namely postoperative complications, length of stay, inhospital and 1-year mortality, and functional performance at 1 year.
Methods
Participants
This prospective cohort study was conducted from October 1, 2011, to September 30, 2012, at the beginning of our integrated hip fracture program. We studied consecutively admitted patients aged more than 60 years to the Department of Orthopaedics in our institution in Singapore, with surgically managed neck of femur, intertrochanteric, or subtrochanteric fracture. We excluded patients with pathological fractures, high impact injuries, and conservatively managed hip fractures.
Data collection
Data were collected on demographics (age, gender, race, premorbid living arrangement), medical comorbidities using the modified Charlson Comorbidity Index (CCI), 7 and type of hip fracture (neck of femur, intertrochanteric, or subtrochanteric). Premorbid mobility status was documented based on ability for community ambulation and need for walking aid. Functional performance in activities of daily living (ADLs) was assessed using the Modified Barthel Index (MBI) as reported by patient or caregiver. 8 Baseline cognitive status was assessed on admission using a locally validated Abbreviated Mental Test (AMT), 9 with a cutoff score of less than eight indicative of cognitive impairment. 10 The preoperative health status was documented using the American Society of Anaesthesiologists (ASA) score. 11 The ASA score was determined by the Anaesthesiology team during routine preoperative assessment. Time to surgery was calculated from time of admission to the time of operation. We defined delay in surgery as surgery performed more than 48 h after admission.
During the implementation of our program, we recorded data on postoperative complications that occurred in the inpatient stay, such as pneumonia, urinary tract infection, acute myocardial infarction, pulmonary embolism, deep vein thrombosis, new stroke, and new pressure sore. We also looked at length of stay and discharge destination. We collaborated with community hospitals where rehabilitation can be done for medically stable patients, and we coordinated with these institutions to allow smooth transition. Telephone follow-ups were done with the patients or their caregivers at 1 year to obtain information on functional performance using the MBI score and 1-year mortality.
Statistical analysis
Demographic data, fracture type, modified CCI, ASA and AMT scores, premorbid mobility, and MBI scores were compared between patients who had early and delayed surgery. Categorical data were described in frequencies and percentages, while continuous data were presented as mean and standard deviation. For the primary objective identifying factors for surgical delay, we performed univariate analyses using two-sample t-test and Mann–Whitney U-test for parametric and nonparametric continuous variables, respectively, and χ 2 test for categorical variables. This was followed by multiple logistic regression analyses including the significant univariate variables and adjusted a priori for age, gender, and cognitive performance to identify independent predictors for delay in surgery.
We compared the outcomes between patients who had surgery within 48 h versus their counterparts with surgery beyond 48 h. To determine the independent effect of surgical timing on significant outcomes in the univariate analysis, multiple regression models were performed, adjusting a priori for age, gender, cognition, comorbidity, and premorbid functional status. Statistical analysis was performed using statistical software StataSE 14.0. Statistical tests were two-tailed, with p value ≤ 0.05 considered statistically significant. Ethics committee approval for this study was obtained from the National Healthcare Group (NHG) Domain Specific Review Board (DSRB).
Results
Five hundred and fifty-four patients were admitted with hip fractures during the study period; 108 patients (19.5%) did not undergo surgery and were excluded from the study. Patients with conservatively managed hip fractures were significantly older compared with their counterparts who underwent surgery (83.7 ± 8.9 years vs. 80.2 ± 8.4 years, p < 0.01). No significant difference was observed in gender and race between the surgically treated and conservatively managed patients.
A total of 446 patients underwent hip fracture surgery and were included in the study. They were predominantly female (75.1%) and of Chinese ethnicity (87.7%). Majority were admitted from home (96.4%) and were community ambulant (72.9%). Most were ambulant without aid (68.2%), and over half of the cohort (56.7%) were fully independent in their basic ADLs.
Factors associated with delay in surgery
One hundred and forty-four (32.3%) patients had surgery within 48 h of admission (Tables 1 and 2). No significant difference was observed in age, gender, ethnicity, and place of residence prior to admission between patients who had early surgery and their counterparts with delayed surgery. Fracture type was similar between groups with early and delayed surgery.
Patient characteristics comparing early versus delayed surgery in hip fracture.
BADL: basic activity of daily living; MBI: Modified Barthel’s Index; AMT: Abbreviated Mental Test; ASA: American Society of Anaesthesiologists; CCI: Charlson’s Comorbidity Index; IQR: interquartile range; SD: standard deviation.
Multiple logistic regressions of factors associated with delay in surgery.
OR: odd ratio; AMT: Abbreviated Mental Test; ASA: American Society of Anaesthesiologists; CI: confidence interval.
We observed a trend for greater prevalence of cognitive impairment at admission in patients with surgical delay (49.4% vs. 39.1% with AMT less than 8, p = 0.06). Higher CCI score (p < 0.01) and higher ASA score (p < 0.01) were significantly associated with delay in surgery. There were only five patients in our cohort of patients who had a score of ASA IV, thus this number was combined with ASA III.
In multiple logistic regression analyses including age, gender, and cognition, ASA score remained significantly associated with delay in surgery. Patients with ASA score III–IV are nine times more likely to have delay in surgery, compared to those with ASA score I (odd ratio (OR) = 9.52, 95% confidence interval (CI): 1.69–53.68; Table 2). We excluded the CCI score in the regression model owing to collinearity with ASA score.
Inpatient and 1-year mortality
Among the patients who underwent surgery, four patients (0.9%) died during the index hospitalization, and while all had surgical delay, the difference in mortality was not statistically significant to the group who had timely surgery. On the other hand, five patients (4.63%) among the conservatively managed cohort passed away during inpatient stay (p <0.01). One-year mortality was significantly higher for the conservatively managed patients compared to the group that underwent surgery (22.2% vs. 7.4%, p < 0.01). Delay in surgery was significantly associated with increased 1-year mortality (9.3% vs. 3.5%, p = 0.03).
Outcomes related to timing of surgery
The predominant postoperative complication was infection, specifically pneumonia and urinary tract infection, accounting for 81.4% of all postoperative complications (Tables 3 and 4). Patients with surgical delay were significantly more likely to experience early postoperative complications (14.4% vs. 3.6%, p < 0.01). Hospital length of stay was significantly higher in the patients with delayed surgery (median 12.8 days with interquartile range (IQR) 9.7–17.6 days vs. 8.35 days with IQR 5.9–10.9 days, p < 0.01). Majority of patients (77.8%) were discharged to community hospitals for rehabilitation. Institutionalization rate was not significantly different between the patients who had early and delayed surgery.
Outcomes comparing early versus delayed surgery in hip fracture.
MBI: Modified Barthel Index; IQR: interquartile range; SD: standard deviation.
Multiple regression models for the effect of surgical timing on clinical outcomes.
OR: odd ratio; CI: confidence interval; AMT: Abbreviated Mental Test; MBI: Modified Barthel Index; CCI: Charlson Comorbidity Index.
a Adjusted for age, gender, AMT score, MBI score on admission, and CCI score.
b p < 0.05.
c p < 0.01.
Patients with surgical delay also had reduced likelihood of return to premorbid mobility at 1 year (39.7% vs. 50.7%, p = 0.03) and more decline in terms of their MBI score compared to the group who had early surgery (−9.29 ± 20.30 vs. −3.89 ± 17.23, p = 0.01).
In multiple regression analyses adjusted for age, gender, cognitive status, comorbidity, and premorbid function, surgical delay remained a significant risk factor for postoperative complications (OR = 3.21; 95% CI: 1.21–8.49), longer hospital length of stay (β = 7.09; 95% CI: 4.22–9.95), and reduced likelihood of returning to premorbid mobility (OR = 0.62; 95% CI: 0.39–0.97) and function (β = −4.67; 95% CI: −8.68 to −0.66).
Discussion
Our study showed that high ASA score was an independent risk factor for surgical delay among older adults presenting with a hip fracture. Poorer outcomes including postoperative complications, longer hospital length of stay, and failure to return to premorbid mobility and function in the year post-fracture were the significant consequences of surgical delay.
The high ASA score was reflective of poorer health and greater severity of comorbid illness. Our study showed that as the ASA score increases, the greater the odds of delayed surgery. Increased comorbidity, as reflected in the CCI score, was also significantly associated with surgical delay. Other studies produced similar results and longer delays in hip fracture surgery were seen with high ASA and CCI scores. 12 –14 These results were not unexpected, as patients with increased comorbidity or severity of illness would likely need more time for medical optimization prior to surgery. Age, cognitive status, and baseline functional status were not significantly associated with surgical delay, consistent with previous literature which also underscored the impact of medical comorbidity on time to surgery. 13
Cognitive performance did not influence the individual clinical decision for surgery in our cohort of patients, although we observed a trend for a greater proportion of patients having impaired performance on the AMT in the surgical delay group, which was also nonsignificant in the multiple regression analysis. Our captured data did not allow differentiation between delirium and dementia as the cause for impaired cognitive performance, but previous studies had not demonstrated delirium or dementia as a cause of surgical delay in hip fracture. 14,15 Lag time from admission to hip fracture repair, however, was associated with preoperative delirium and increased rates of postoperative delirium among patients with dementia. 15,16 Uncontrolled pain contributes to delirium and agitated behavior in patients with dementia, thus older adults with cognitive impairment would benefit from early surgery to help with pain control.
Increased hospital length of stay had been previously demonstrated in hip fracture patients who had increased time to surgery. 14,17 Our study also showed that surgical delay increased median length of stay by 50% compared to the group who had timely surgeries. The significant association remained after adjustment for age, gender, comorbidity, and functional status. Apart from the risk of nosocomial infections, increased hospital length of stay also leads to rising cost and burden to available resources. Thus, in patients who are medically fit, timely surgery would be beneficial to the patients and the hospital system as well.
Consistent with earlier studies demonstrating the impact of delayed hip fracture surgery in both short- and long-term mortality, 18,19 we observed significantly increased 1-year mortality among patients with surgical delay. The odds of mortality at 1 year remain high in the group with surgical delay with a trend for significance (p = 0.06) after adjusting for age, gender, comorbidity, and functional status.
Interestingly, our inhospital and overall 1-year mortality rate was lower than that reported in the literature. 20 This may be due to two factors: first, the patients who went for surgery were younger and likely fitter than the conservatively managed patients who were excluded from the study. Conservatively managed patients were largely patients who declined surgery as they had poor premorbid medical conditions and function resulting in high anesthetic risk. Some declined surgery due to cultural reasons. This is not dissimilar to the 25.9% managed conservatively in some Asian countries like India. 21 Second, the implementation of an integrated hip fracture program. In our model of care, there were daily orthopedic and orthogeriatric ward rounds with a weekly multidisciplinary round. Patients were closely monitored during the immediate postoperative period to prevent and treat early postoperative complications. A meta-analysis done in 2014 showed that orthogeriatric collaboration in the care of hip fracture patients was associated with reduced inhospital and long-term mortality rate. 20 Low mortality rates were also seen in the Hong Kong Orthogeriatric Care model where inpatient mortality was low at 3% and 1-year mortality at 18.5%. 22
Surgical delay was associated with greater than 3-fold increased odds for early postoperative complications, predominantly pneumonia and urinary tract infection. This increased risk was consistent with other studies demonstrating increased rates of pressure sores, pneumonia, and urinary tract infections among patients who had delayed surgery. 14,18,19 Surgical delay results in prolonged bed rest leading to the development of pressure sores and infections.
We observed sustained benefit of early surgery in elderly hip fracture patients up to the year postoperatively, with surgical delay independently reducing the likelihood of return to premorbid mobility at 1-year by approximately 50%. Additionally, there was significantly less functional decline in ADLs at 1-year in patients who underwent early hip fracture surgery. Better functional outcomes with early surgery were observed, despite there being no difference in premorbid mobility and functional performance. Effect of time to surgery on long-term functional recovery has been inconsistent across many studies, 23 –26 likely reflecting the heterogeneity of functional trajectory and its multifactorial contributions, although there was no difference in readmission rates between the groups with and without surgical delay. 23 Further, the process of functional recovery may be prolonged for elderly patients and potential for improvement still exists after the acute period. 27,28 Thus, community integration is valuable in the sustained delivery of rehabilitation services for hip fracture patients beyond the acute hospital stay.
In our study, only 32.3% of the patients had surgery within 48 h of admission. This was at the start of our integrated program. This is lower than that reported by the UK National hip fracture database in 2012, where 83% of cases underwent surgery in 48 h. 29 Early surgery was one of the outcomes measured in our iteration of the hip fracture program. Several quality improvement measures were initiated in stages throughout the 5-year program, resulting in improved outcomes after the first year. The team addressed prioritization of hip fracture patients in operating theatre, increased awareness of the benefits of early surgery, and worked with the anesthetists in standardizing the guidelines for fitness of operation. By 2015, 70.1% of hip fracture patients in the Integrated Hip Fracture Program now have surgery within 48 h of admission.
We acknowledge several limitations in this study. Only patient-related factors that could potentially impact on surgical timing were captured. Although logistical and system-related factors can contribute to delayed surgical care, 14 the development of clinical pathways aims to address these variables so that the effect is minimized. A marked improvement in the percentage of timely surgeries was seen at the end of our program through fine-tuning of operational systems and clinical guidelines, but we do not consider this as a limitation of our study as it does not bias the allocation into our comparison groups. We lacked data on functional performance prior to hospital discharge and thus are unable to ascertain if surgical delay could have contributed to functional decline that in turn affected 1-year functional outcomes.
Conclusion
This study highlights the importance of timely surgery in elderly patients with hip fracture. Delayed surgery is associated with worse short- and long-term outcomes. Patients who are medically fit should be expedited for surgery. Factors contributing to long-term functional recovery are still unclear and can be the focus for future research.
Footnotes
Declaration of conflicting interests
The author(s) declare that there are no potential conflicts of interest with respect to the authorship and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.