We found no evidence that cognitive function four months after surgery was improved in patients treated pre- and postoperatively in an acute geriatric ward, compared to usual care in an orthopaedic ward. There was, however, a trend that the intervention had a positive effect on mobility on patients not admitted from nursing homes.
Why so limited effect of our model?
5.2.1
Despite the comprehensive intervention, the effect on the primary endpoint was limited. There are several possible explanations for this. First, the choice of endpoint might have been too audacious. For the intervention to be effective in this regard, two presuppositions had to be true. First, the primary outcome assumes that delirium lies on the causal pathway towards the development of dementia. The major criticism against studies that implies that delirium has a negative impact on cognitive trajectories, is that delirium is only unmasking dementia and is not causing it. If this is true, one could not expect delirium prevention to have any effect on long term outcomes. As described earlier, a growing amount of evidence suggests that delirium can lead to dementia, but since delirium occurs in relation to acute illness it is difficult to design good prospective studies to address this very important question.
The second presupposition was that the orthogeriatric intervention had to be effective in delirium prevention. Other studies have shown that geriatric intervention is effective in reducing delirium in hip fracture patients, also when the intervention is limited to a liaison service (Marcantonio et al., 2001) and an Inpatient Geriatric Consultant Team(Deschodt et al., 2012). Since the limited geriatric intervention given in these studies was effective in reducing delirium, one should expect that continuously pre- and postoperative geriatric care, as provided in our model, should be even more effective. Our intervention failed, however, to prevent delirium or reduce delirium severity. This was surprising and can in part be explained by the good quality of usual care in our study. Compared to other models reported in the literature, waiting time for surgery was short in our study. Introduction of an orthogeriatric service is usually reported to reduce waiting time for surgery, but in our study it was two
hours longer for the patients in the acute geriatric ward. This difference was not statistically significant, but could nevertheless have had a negative impact for patients allocated to intervention since waiting time for surgery is known to have a sincere negative impact on outcomes in hip fracture patients(Pioli et al., 2012b).
The personnel in the orthopaedic ward had also experience from earlier orthogeriatric models and was familiar with usual strategies for delirium prevention (use of single rooms, adequate management of pain, orientation etc.). In order to obtain a precise delirium diagnosis was the personnel at the orthopaedic ward daily interviewed regarding cognitive changes of the patients, and this inevitably raised the awareness of delirium in the orthopaedic ward.
But most importantly were several factors with the orthogeriatric model not optimal. The ward was often over-crowded. During the inclusion period was on average 101 % of the beds occupied. This means that usually there were more patients in the ward than it had capacity to serve so patients had to be treated in the corridor. In order to avoid randomization violations, was the ward was instructed (and managed!) to admit all randomized hip fracture patients. Since patients tend to come in clusters, there were times when several patients had to be treated in the corridor, and the work load was too large to handle and it inevitably influenced quality of care. The orthopaedic ward was equally staffed as the acute geriatric ward and had a 90 % bed occupancy during the project period. The orthopaedic patients are in general less demanding than a geriatric patient.
The hip fracture patients included in the trial was the only surgical patients in the acute geriatric ward, and some of the personnel never got used to handle orthopaedic patients. Especially were many nervous to mobilize the patients postoperatively. Before the inclusion started we had a pilot phase of 14 months, and this was probably too short for implementation of procedures. The fact that the hip fracture patients often represented extra work load and was an unfamiliar patient category impacted negatively on the enthusiasm regarding the project. The hip fracture patients are demanding patients, and one should not underestimate the importance of a factor as enthusiasm.
Despite the lack of effect on the primary endpoint, and the weaknesses with our orthogeriatric model, it is important to point out that the intervention had a positive effect on mobilisation, the most important secondary endpoint in our trial. A difference on SPPB of 0.5 is considered clinically meaningful, and the effect seen in our study (6 v 4 points) is likely to be important
and should be further explored in future studies. Data from the subgroup of patients that had mobilization recorded with the activPAL™ body-worn sensor system, indicated that patients in the acute geriatric ward, received a more intensive mobilization compared to patients in the orthopedic ward.