PRISMA-7: A case-finding tool to identify older adults with moderate to severe disabilities

Abstract

Many comprehensive rating scales have been developed to assess disabilities. These assessments, which require significant amounts of time, are usually performed by trained professionals. A simple case-finding instrument is needed to quickly identify older persons with potential disabilities, who then should undergo comprehensive assessments. In a cross-sectional study of 594 community-dwelling older subjects, we developed a questionnaire from an initial list of 23 yes/no questions, and compared it with an existing one to determine their relative ability to identify older persons with moderate to severe disabilities. Initially designed to identify older people with any disability, the existing seven-question tool also provided to be a good marker of significant disabilities, with a cut-off score of three or more positive answers. The sensitivity and specificity of this cut-off are 78.3% and 74.7%, respectively. These validity indices support the use of this questionnaire in identifying older persons with potential moderate to severe disabilities with a view to referring them for more comprehensive assessment.

Introduction

A significant proportion of older adults live at home with moderate to severe disabilities (Hébert et al., 1997a). A case-finding tool offers the only means for early identification of these individuals short of comprehensive assessment. In an optimal healthcare system, all older persons presenting mild, moderate, and severe disabilities would be identified and assessed, and the appropriate interventions delivered. In practice, however, not even all individuals with moderate to severe disabilities are detected and identified by clinicians. A Lancet Editorial pointed out some causes, lack of time for evaluation, underreporting by patients, overly long and complex questionnaires developed for research purposes, that still apply (Editorial, 1991). A comment by Ebrahim (1999) pointed out that this crucial problem was persisting as it still is today.

Other authors have discussed the difficulties related to adequately screening older people (Kasper et al., 1999, Ferrucci et al., 2004). The objective is different if the purpose is to screen for geriatric health problems or to recognize prevalent disabilities in order to prevent or delay functional decline. We focus on the latter in this article. In addition, we also distinguish between case-finding and screening herein, screening refers to identifying individuals who will be affected by a condition (prediction of incident cases), while case-finding refers to identifying individuals who are actually affected (current state: prevalent cases) (Muir Gray et al., 1985). However, since screening and case-finding are often synonymous in the literature, we used both terms in searching for existing tools.

Existing studies aimed at targeting older people often appear to focus on identifying general health problems, even if mention is made of disability (Lachs et al., 1990, Pathy et al., 1992). To our knowledge, very few have focused on disabilities for validity criteria (Bowns et al., 1991, Hébert et al., 1996a, Hébert et al., 1996b, Mateev et al., 1998, McCusker et al., 1998, McCusker et al., 1999, Kasper et al., 1999, Brody et al., 2002, Dendukuri et al., 2004), although some of them presented a detailed validation process and information on sensitivity and specificity (Bowns et al., 1991, Hébert et al., 1996a, Hébert et al., 1996b, McCusker et al., 1998, McCusker et al., 1999, Brody et al., 2002, Dendukuri et al., 2004). One study used an overly broad criterion (dependence on another person for daily care sometime during the year (Brody et al., 2002)) and another used a construct validity device (Bowns et al., 1991). One study presented both prospective and prevalence aspects (McCusker et al., 1999); some studies presented only a prospective aspect (Hébert et al., 1996a, Brody et al., 2002, Dendukuri et al., 2004), while others only a prevalence aspect (Hébert et al., 1996b, McCusker et al., 1998).

The definition of disability requires attention. Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL) often occult other dimensions of disability, such as mental status and mobility, that should receive more attention (Hébert et al., 1996a, Kasper et al., 1999). While many authors were in agreement on this, very few studies presented validation for case-finding with multidimensional disabilities. Two studies (Hébert et al., 1996b, McCusker et al., 1998) reported validation with a clinical and multidimensional disability tool called functional autonomy measurement system (abbreviated from French as SMAF) rating scale (Hébert et al., 2001a). The first study reported data from an instrument used in an emergency department (ED) (McCusker et al., 1998). The instrument unfortunately showed poor sensitivity (≤60%) in identifying at least one disability on each of the five SMAF sub-scales. No results were reported with a cut-off on the total SMAF score. The second study (Hébert et al., 1996b) presented a tool for identifying older people with any disability, but did not appear widely used since it identified too large a part of the aged population (when including mild disabilities). Focusing on moderate to severe disabilities does appear more clinically relevant and feasible (Hébert et al., 2003).

The need for a case-finding tool to identify older people with potential moderate to severe disabilities became evident during the implementation of an integrated health network for older adults in Quebec (the Program on research for integrating services for the maintenance of autonomy (PRISMA Project), Hébert et al., 2003). In attempting to find an instrument for use in different settings, we tested short questionnaires based on elders’ perception. Such a tool with good validity indices could then be included in routine annual examinations (systematic approach) or when older people contact clinicians or health services (opportunistic approach).