Since a high proportion believe that most of the ADL items are important in terms of functional decline and assess for such items, it is likely that the physicians considered such items in the calculation of a clinically significant point drop. Such calculations that are based on high importance and assessment of the ADL items have resulted in a low clinically significant point drop. This information demonstrates that when creating a clinical decision rule it is important to distinguish between different patients with different injury severity.
Measuring the basic ADL separately helped us to identify the higher weight of the basic ADL over the IADL items. In other words, a smaller clinically significant point drop in the basic ADL compared to the combined basic ADL/IADL items indicates the importance of the basic ADL over the IADL items in general despite both being relevant to functional decline. This implies that one needs to be cautious when using the overall OARS ADL Scale because the basic ADL items and IADL items are not weighted equally. These findings need to be considered for the outcome measure of any clinical decision tool for identifying elderly patients at high risk of functional decline after a minor injury.
Although our results indicated that 90% of geriatricians require a clinical decision rule with a sensitivity of up to 90% before they would consider using it, the results might indicate physicians’ previous habits of using highly sensitive tools and as such prompt them to ask for such high sensitivities. Despite the fact that the most commonly used tool (ISAR) has a sensitivity of 81%,up to 75% of physicians in our survey indicated that they would require a more sensitive tool than 81%. In our study, only up to 25% of the physicians indicated that they would accept a clinical decision rule with a sensitivity of up to 80%. If indeed the majority of the physicians require a clinical decision rule with a sensitivity of up to 90%, such a rule might be very welcomed by physicians and a major step to having the physicians start using it.
Assessment and Relevance of Activities of Daily Living to Functional Decline
A high proportion of geriatricians reported that most of the ADL items are important in terms of functional decline and they assess for most of the items. The key informant interviews we had with the physicians revealed that they were aware of different kinds of ADL and that they would assess for these different activities as needed. The key informant interviews also showed that geriatricians use standard assessment tools, as confirmed by the results showing that geriatricians assessed for some ADL activities even when they thought the tasks were not important to functional decline. The high proportion of physicians assessing for most of the ADL items might also be a result of multiple follow-up visits that provide the geriatricians more opportunities to assess for any remaining ADL items.
We achieved a satisfactory overall response rate of 70.5% which was above expectations. Our overall response rate exceeded the mean response rates of 54%and 61% reported by two systematic reviews of physician postal surveys. Such a high response rate from physicians is an indication of the relevance of this study. It could also be a result of a rigorous methodological approach we took to help obtain higher response rates. The key informant interviews, the cognitive interviews, the pilot testing of the surveys, as well as the short and concise questionnaire with incentives to half of the physicians and a special contact, aided greatly in obtaining such a high response rate with very few missing data. Although non-response bias is unlikely with high response rates such as ours, we still investigated for non-response bias using the region and language of the questionnaire. Although there could still be a possibility of non-response bias, our high response rate and tests for non-response bias imply valid and accurate results.
This study has a few limitations. The sample of geriatricians selected was based on what was available in the Canadian Medical Directory as of August 23, 2011. We found a few physicians that had retired or moved who were still in the directory. Another potential limitation is the possibility of not having all practising physicians included in the directory, which could lead to a possibly biased sample. However, these limitations are minimal as the Canadian Medical Directory claims an accuracy of 97% or better. There is also a possibility of misinterpretation of the survey questions on the importance of the basic ADL/IADL items with respect to functional decline. There is a possibility that the physicians assumed different injuries when providing their opinions on the point drops—some injuries, such as finger injuries, would have different implications than an injury to the leg.
Functional decline can be measured in different ways with various instruments including the Barthel Index, Functional Independence Measure, Katz ADL,Lawton IADL Scales, Functional Autonomy Measurement System (or Système de Mesure de l’Autonomie Fonctionnelle [SMAF]), Functional Status Questionnaire, and the Older Americans Resources and Services (OARS) ADL Scale. A potential limitation of this study is that we used the OARS ADL Scale which attributes an equal weight to each ADL and IADL, instead of some of the other scales with weights given to different ADL item. However, since the OARS ADL Scale has been validated in the ED and is anticipated to be used in the ED, we decided to use such a tool.
Our results indicate that 90% of geriatricians consider a drop in function of at least 2 points in the basic ADL/IADL as clinically significant. Our results also indicate that a tool with a sensitivity of 90% to detect patients at risk of functional decline six months post-injury would meet or exceed the sensitivity required by most geriatricians. The majority of the geriatricians indicated that only 1 point drop is required to imply functional decline when only the 7 basic ADL items are considered.
Although there was some disagreement among physicians on a clinically significant point drop when the elderly patients have support at home, the majority were satisfied with a lower point drop that is the same as the point drop used to define functional decline when the elderly patient did not have support at home. These results identify a clear, clinically important outcome for any clinical decision tool to identify elderly patients at high risk of functional decline 6 months after sustaining a minor injury. This study clearly defines what is considered clinically significant functional decline following a “minor injury.”