Development of the computer-adaptive version of the Late-Life Function and Disability Instrument

Long-term follow-up of clinical trial participants: Predictors of post-trial response in older subjects

BACKGROUND AND OBJECTIVE

The post-trial follow-up (PTFU) phase of a clinical trial can provide important information on maintenance of intervention effects. However, approaches for the PTFU are rarely described. This short communication describes our process for PTFU that involved recontacting older subjects who participated in a clinical trial between 2015 and 2019. We also describe correlates of response to our PTFU survey.

METHODS

The parent clinical trial aimed to reduce depression symptoms among older spousally-bereaved adults. We attempted to recontact our sample during the early stages of the COVID-19 pandemic. Using logistic regression, we examined physical health, depression symptoms, cognitive status, and disability as correlates of participant response to the PTFU phase.

RESULTS

Forty-two percent of participants responded to the PTFU survey. Disability - or the inability to participate in major life tasks and social roles - was significantly associated with response. Participants with greater disability were less likely to respond to the PTFU survey.

CONCLUSIONS

Older adults with disabilities may need alternative and supportive strategies for engaging in the PTFU phase.

CLINICAL TRIALS REGISTRATION

NCT02631291.

A systematic review of predictive accuracy via c-statistic of preoperative frailty tests for extended length of stay, post-operative complications, and mortality

Frailty, as an age-related syndrome of reduced physiological reserve, contributes significantly to post-operative outcomes. With the aging population, frailty poses a significant threat to patients and health systems. Since 2012, preoperative frailty assessment has been recommended, yet its implementation has been inhibited by the vast number of frailty tests and lack of consensus. Since the anesthesiologist is the best placed for perioperative care, an anesthesia-tailored preoperative frailty test must be simple, quick, universally applicable to all surgeries, accurate, and ideally available in an app or online form. This systematic review attempted to rank frailty tests by predictive accuracy using the c-statistic in the outcomes of extended length of stay, 3-month post-operative complications, and 3-month mortality, as well as feasibility outcomes including time to completion, equipment and training requirements, cost, and database compatibility. Presenting findings of all frailty tests as a future reference for anesthesiologists, Clinical Frailty Scale was found to have the best combination of accuracy and feasibility for mortality with speed of completion and phone app availability; Edmonton Frailty Scale had the best accuracy for post-operative complications with opportunity for self-reporting. Finally, extended length of stay had too little data for recommendation of a frailty test. This review also demonstrated the need for changing research emphasis from odds ratios to metrics that measure the accuracy of a test itself, such as the c-statistic.

Responsiveness of the late life disability instrument to pulmonary rehabilitation in people with COPD

PURPOSE

To establish the responsiveness of the disability component of the Late Life Function and Disability Instrument (LLDI) and its Computer Adaptive Test (LLDI-CAT) in people with chronic obstructive pulmonary disease (COPD).

METHOD

Participants completed the LLDI, LLDI-CAT and measures of physical function, health-related quality of life (HRQOL) and symptom severity before and after pulmonary rehabilitation (PR), and global rating of change (GRC) scales at the end of PR. Responsiveness was explored by calculating correlations between LLDI and LLDI-CAT change scores and change scores on the other measures, and calculating the area under the receiver operating characteristic curve (AUC) for the ability of the LLDI and LLDI-CAT to discriminate between participants who were improved versus unchanged. We hypothesized fair correlations (-0.3 to -0.5 or 0.3 to 0.5) with other measures and considered an AUC≥0.7 acceptable. Minimal important differences (MIDs) were estimated using anchor- and distribution-based approaches.

RESULTS

Fifty participants (mean (SD) age 69.8 (7.9) years) completed the study. Only the limitation dimension of the LLDI showed improvement at follow-up (z = 2.4, p = 0.018) and was able to discriminate between participants who were improved versus unchanged (AUC 0.7 (95% CI 0.6-0.9)). Correlations between change scores were as hypothesized between the participation measures and measures of at least two other constructs.

CONCLUSION

This study provides MID values for the LLDI and LLDI-CAT to support their clinical application. The limitation dimension of the LLDI appears to be particularly responsive to PR in people with COPD.

A digital health intervention to stabilize the 24-hour rhythm of sleep, meals, and physical activity for reducing depression among older bereaved spouses: Protocol for a randomized controlled trial

BACKGROUND

Despite the high prevalence of depression and disruption to 24-h sleep-wake routines following the death of a spouse in late-life, no bereavement interventions have been developed to re-entrain a regular sleep-wake routine among older widow(er)s. We describe the rationale and methodology of the NIH-funded WELL Study (Widowed Elders' Lifestyle after Loss), a randomized controlled trial (RCT) comparing the efficacy of a digital health intervention (DHI) to enhanced usual care (EUC) arm for reducing depression symptoms in older spousally-bereaved adults.

METHODS

We will randomize approximately 200 recently bereaved (<12 months) adults aged 60+ years to one of two 12-week interventions: digital monitoring of the timing and regularity of sleep, meals, and physical activity plus weekly motivational health coaching; or enhanced usual care consisting of weekly telephone calls and similar assessment schedules. Participants will complete self-report and clinical assessments at baseline, post-intervention, and 3-, 6-, and 12-months post-intervention, and objective actigraphic assessments of their 24-h rest-activity rhythm (RAR) at baseline and 1-, 2-, and 3-months during the intervention. The primary outcome is change in depression symptoms burden (using the Hamilton Rating Scale for Depression) from pre- to post-intervention and over 12 months of follow-up.

DISCUSSION

WELL Study findings will inform the development of widely generalizable and scalable technology-based interventions to support bereaved spouses in community-based settings. Clinical http://Trials.gov Identifier: NCT04016896.

A Brief Measure of Life Participation for People with COPD: Validation of the Computer Adaptive Test Version of the Late Life Disability Instrument

Computer-adaptive tests use respondents' answers to previous questions to select the subsequent questions. They are gaining popularity for their increased measurement precision and decreased administration time compared to static questionnaires. The purpose of this study was to estimate the test-retest reliability and construct validity of the computer-adaptive test version of a participation measure, the Late Life Disability Instrument (LLDI-CAT) for people with COPD and to compare scores and administration time with those of the static LLDI. Among 76 older adults with COPD, scores on the LLDI-CAT were compared to scores on measures of related constructs, between groups based on symptom severity, prognosis and frailty phenotype, and to scores on the static LLDI. A subsample of 28 people completed the LLDI-CAT a second time within one week of the initial administration for test-retest reliability. The LLDI-CAT had very good test-retest reliability (ICC_2,1 0.88; SEM 2.74 points), fair correlations with physical function (r = 0.37-0.50), anxiety (r=-0.42), and depression (r=-0.50), fair to moderately-strong correlations with quality of life (r = 0.48-0.63), and strong correlation with the static LLDI limitation domain (r = 0.80). The LLDI-CAT scores differed between people with different symptom severity, prognosis and frailty phenotype (p ≤ 0.004). The mean administration time for the LLDI-CAT was 3.3 (1.5) minutes, less than that of the static LLDI at 6.3 (2.8) minutes (p < 0.001). The LLDI-CAT demonstrates evidence of test-retest reliability and construct validity, and correlates well with the limitation domain of the static LLDI for people with COPD. The LLDI-CAT can be used to assess participation for this population.

Safety, Reactogenicity, and Health-Related Quality of Life After Trivalent Adjuvanted vs Trivalent High-Dose Inactivated Influenza Vaccines in Older Adults: A Randomized Clinical Trial

IMPORTANCE

Trivalent adjuvanted inactivated influenza vaccine (aIIV3) and trivalent high-dose inactivated influenza vaccine (HD-IIV3) are US-licensed for adults aged 65 years and older. Data are needed on the comparative safety, reactogenicity, and health-related quality of life (HRQOL) effects of these vaccines.

OBJECTIVE

To compare safety, reactogenicity, and changes in HRQOL scores after aIIV3 vs HD-IIV3.

DESIGN, SETTING, AND PARTICIPANTS

This randomized blinded clinical trial was a multicenter US study conducted during the 2017 to 2018 and 2018 to 2019 influenza seasons. Among 778 community-dwelling adults aged at least 65 years and assessed for eligibility, 13 were ineligible and 8 withdrew before randomization. Statistical analysis was performed from August 2019 to August 2020.

INTERVENTIONS

Intramuscular administration of aIIV3 or HD-IIV3 after age-stratification (65-79 years; ≥80 years) and randomization.

MAIN OUTCOMES AND MEASURES

Proportions of participants with moderate-to-severe injection-site pain and 14 other solicited reactions during days 1 to 8, using a noninferiority test (5% noninferiority margin), and serious adverse events (SAE) and adverse events of clinical interest (AECI), including new-onset immune-mediated conditions, during days 1 to 43. Changes in HRQOL scores before and after vaccination (days 1, 3) were also compared between study groups.

RESULTS

A total of 757 adults were randomized, 378 to receive aIIV3 and 379 to receive HD-IIV3. Of these participants, there were 420 women (55%) and 589 White individuals (78%) with a median (range) age of 72 (65-97) years. The proportion reporting moderate-to-severe injection-site pain, limiting or preventing activity, after aIIV3 (12 participants [3.2%]) (primary outcome) was noninferior compared with HD-IIV3 (22 participants [5.8%]) (difference -2.7%; 95% CI, -5.8 to 0.4). Ten reactions met noninferiority criteria for aIIV3; 4 (moderate-to-severe injection-site tenderness, arthralgia, fatigue, malaise) did not. It was inconclusive whether these 4 reactions occurred in higher proportions of participants after aIIV3. No participant sought medical care for a vaccine reaction. No AECI was observed. Nine participants had at least SAE after aIIV3 (2.4%; 95% CI,1.1% to 4.5%); 3 had at least 1 SAE after HD-IIV3 (0.8%; 95% CI, 0.2% to 2.2%). No SAE was associated with vaccination. Changes in prevaccination and postvaccination HRQOL scores were not clinically meaningful and not different between the groups.

CONCLUSIONS AND RELEVANCE

Overall safety and HRQOL findings were similar after aIIV3 and HD-IIV3, and consistent with prelicensure data. From a safety standpoint, this study's results support using either vaccine to prevent influenza in older adults.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03183908.

The Nursing Home Physical Performance Test: A Secondary Data Analysis of Women in Long-Term Care Using Item Response Theory

Background and Objectives

The Nursing Home Physical Performance Test (NHPPT) was developed to measure function among nursing home residents using sit-to-stand, scooping applesauce, face washing, dialing phone, putting on sweater, and ambulating tasks. Using item response theory, we explore its measurement characteristics at item level and opportunities for improvements.

Research Design and Methods

We used data from long-term care women. We fitted a graded response model, estimated parameters, and constructed probability and information curves. We identified items to be targeted toward lower and higher functioning persons to increase the range of abilities to which the instrument is applicable. We revised the scoring by making sit-to-stand and sweater items harder and dialing phone easier. We examined changes to concurrent validity with activities of daily living (ADL), frailty, and cognitive function.

Results

Participants were 86 years old, had more than three comorbidities, and a NHPPT of 19.4. All items had high discrimination and were targeted toward the lower middle range of performance continuum. After revision, sit-to-stand and sweater items demonstrated greater discrimination among the higher functioning and/or greater spread of thresholds for response categories. The overall test showed discrimination over a wider range of individuals. Concurrent validity correlation improved from 0.60 to 0.68 for instrumental ADL and explained variability (R2) from 22% to 36% for frailty.

Discussion and Implications

NHPPT has good measurement characteristics at the item level. NHPPT can be improved, implemented in computerized adaptive testing, and combined with self-report for greater utility, but a definitive study is needed.

Validation and responsiveness of the Late-Life Function and Disability Instrument Computerized Adaptive Test in community-dwelling stroke survivors

BACKGROUND

Follow-up of stroke survivors is important to objectify activity limitations and/or participations restrictions. Responsive measurement tools are needed with a low burden for professional and patient.

AIM

To examine the concurrent validity, floor and ceiling effects and responsiveness of both domains of the Late-Life Function and Disability Index Computerized Adaptive Test (LLFDI-CAT) in first-ever stroke survivors discharged to their home setting.

DESIGN

Longitudinal study.

SETTING

Community.

POPULATION

First ever stroke survivors.

METHODS

Participants were visited within three weeks after discharge and six months later. Stroke Impact Scale (SIS 3.0) and Five-Meter Walk Test (5MWT) outcomes were used to investigate concurrent validity of both domains, activity limitations, and participation restriction, of the LLFDI-CAT. Scores at three weeks and six months were used to examine floor and ceiling effects and change scores were used for responsiveness. Responsiveness was assessed using predefined hypotheses. Hypotheses regarding the correlations with change scores of related measures, unrelated measures, and differences between groups were formulated.

RESULTS

The study included 105 participants. Concurrent validity (R) of the LLFDI-CAT activity limitations domain compared with the physical function domain of the SIS 3.0 and with the 5MWT was 0.79 and -0.46 respectively. R of the LLFDI-CAT participation restriction domain compared with the participation domain of the SIS 3.0 and with the 5MWT was 0.79 and -0.41 respectively. A ceiling effect (15%) for the participation restriction domain was found at six months. Both domains, activity limitations and participation restrictions, of the LLFDI-CAT, scored well on responsiveness: 100% (12/12) and 91% (12/11) respectively of the predefined hypotheses were confirmed.

CONCLUSIONS

The LLFDI-CAT seems to be a valid instrument and both domains are able to detect change over time. Therefore, the LLFDI-CAT is a promising tool to use both in practice and in research.

CLINICAL REHABILITATION IMPACT

The LLFDI-CAT can be used in research and clinical practice.

The Positive Benefits of Negative Movement Patterns Following Total Knee Arthroplasty

Introduction:

Eccentric (negative) resistance exercise of the legs using specialized machines has been reported to be useful and often superior to standard exercise following total knee arthroplasty (TKA). Movements that utilize body mass and gravity as a mode of eccentric resistance exercise in a more pragmatic rehabilitation paradigm may also be useful in reversing chronic muscle impairments observed years following surgery. This study explores whether an eccentrically biased, body mass resistance exercise induces greater magnitude of sagittal plane extensor angular impulse of the support torque and individual net joint torque contributions during both squatting and lunging movement patterns 6 weeks following TKA.

Methods:

Cross-sectional laboratory-based study design including 10 patients following primary unilateral TKA (6.5 ± 0.8 weeks.). All patients completed 3 trials of the squat and lunge movement pattern under both a concentric and an eccentric condition. Extensor angular impulse of the support torque and net joint torque contributions were calculated by integrating the joint torque versus time curves. A Two-way analysis of covariance was conducted and contracts of clinical interest were computed using Wald posttest. P Values for all pairwise comparisons were adjusted for multiplicity using Bonferroni multiple comparison procedure.

Results:

The eccentric condition, compared to the concentric condition, displayed larger magnitude of extensor angular impulse during both the squat (P < .001) and lunge (P < .001) movement patterns for the support torques. Similarly, the eccentric condition, compared to the concentric condition, displayed larger magnitude of extensor angular impulse of the hip, knee, and ankle (P < .001) during both movement patterns.

Conclusion:

Eccentrically biased, body mass movement exercises can produce higher levels of extensor angular impulse on the surgical limb in patients early after TKA. Patients in this study were able to tolerate the higher extensor angular impulse demands and performed the eccentrically biased conditions (without specialized machines) that could be beneficial in postoperative rehabilitation.

Self-Reported Function More Informative than Frailty Phenotype in Predicting Adverse Postoperative Course in Older Adults

BACKGROUND/OBJECTIVE

Current preoperative assessment tools such as the American College of Surgeons Surgical Risk Calculator (ACS Calculator) are suboptimal for evaluating older adults. The objective was to evaluate and compare the performance of the ACS Calculator for predicting risk of serious postoperative complications with the addition of self-reported physical function versus a frailty score.

DESIGN

Prospective cohort.

SETTING

Two tertiary care academic medical centers in Massachusetts.

PARTICIPANTS

Individuals aged 65 and older undergoing any surgery with a risk of serious complication of 5% or greater (N = 403).

MEASUREMENTS

We measured self-reported physical function using the Late-Life Function and Disability Instrument (LLFDI FUNCTION) and frailty phenotype (FP), which has a score ranging from 0 to 5 based on slow gait speed, weak handgrip, exhaustion, weight loss, or low activity. Using c-statistic and net classification improvement (NRI), we then analyzed capability of LLFDI-FUNCTION versus FP to improve the ACS Calculator for predicting an adverse postoperative course (serious complication, discharge to nursing home, readmission, death within 30 days of surgery). Increase in c-statistic and net reclassification improvement (NRI) for LLFDI-FUNCTION versus FP in addition to the ACS Calculator for predicting an adverse postoperative course (serious complication, discharge to nursing home, readmission, death within 30 days of surgery) RESULTS: Over 30 days, 26% of participants developed an adverse postoperative course. The increase in c-statistic for the ACS Calculator (baseline value 0.645) was slightly greater with LLFDI-FUNCTION (0.076) than with FP (0.058), with a bootstrapped difference in c-statistic of 0.005 (95% confidence interval = 0.002-0.007). NRI was also better with LLFDI-FUNCTION.

CONCLUSION

The LLFDI-FUNCTION predicted postoperative complications slightly better than the FP. Further studies are needed to confirm these findings and validate the use of the LLFDI-FUNCTION with the ACS Calculator for preoperative assessments of older adults.

Patient-Reported Measures of Physical Function in Knee Osteoarthritis

Knee osteoarthritis is a common cause of an array of functional limitations in older adults, and the accurate assessment of such limitations is critical for practicing clinicians and scientists. Patient-reported measures are a valuable resource to track the type and severity of limitation, although the psychometric performance of each instrument should be thoroughly evaluated before adoption. This article reviews the validity, reliability, sensitivity to change, and responsiveness of 3 patient-reported measures of physical function: the Western Ontario and McMaster Universities Osteoarthritis Index, the Knee Injury and Osteoarthritis Outcome Score, and the Patient Reported Outcomes Measurement Information System Physical Function scale.

Gait Speed Predicts Incident Disability: A Pooled Analysis

BACKGROUND

Functional independence with aging is an important goal for individuals and society. Simple prognostic indicators can inform health promotion and care planning, but evidence is limited by heterogeneity in measures of function.

METHODS

We performed a pooled analysis of data from seven studies of 27,220 community-dwelling older adults aged 65 or older with baseline gait speed, followed for disability and mortality. Outcomes were incident inability or dependence on another person in bathing or dressing; and difficulty walking ¼ - ½ mile or climbing 10 steps within 3 years.

RESULTS

Participants with faster baseline gait had lower rates of incident disability. In subgroups (defined by 0.2 m/s-wide intervals from <0.4 to ≥ 1.4 m/s) with increasingly greater gait speed, 3-year rates of bathing or dressing dependence trended from 10% to 1% in men, and from 15% to 1% in women, while mobility difficulty trended from 47% to 4% in men and 40% to 6% in women. The age-adjusted relative risk ratio per 0.1 m/s greater speed for bathing or dressing dependence in men was 0.68 (0.57-0.81) and in women: 0.74 (0.66-0.82); for mobility difficulty, men: 0.75 (0.68-0.82), women: 0.73 (0.67-0.80). Results were similar for combined disability and mortality. Effects were largely consistent across subgroups based on age, gender, race, body mass index, prior hospitalization, and selected chronic conditions. In the presence of multiple other risk factors for disability, gait speed significantly increased the area under the receiver operator characteristic curve.

CONCLUSION

In older adults, gait speed predicts 3 year incidence of bathing or dressing dependence, mobility difficulty, and a composite outcome of disability and mortality.

Non-pharmacological interventions for adults with mild cognitive impairment and early stage dementia: An updated scoping review

The purpose of this scoping review was to examine the science related to non-pharmacological interventions designed to slow decline for older adults with Mild Cognitive Impairment or early-stage dementia. We reviewed 32 unique randomized controlled trials that employed cognitive training (remediation or compensation approaches), physical exercise, or psychotherapeutic interventions that were published before November 2014. Evidence suggests that cognitive training focused on remediation and physical exercise interventions may promote small improvements in selected cognitive abilities. Cognitive training focused on compensation interventions and selected psychotherapeutic interventions may influence how cognitive changes impact daily living. However, confidence in these findings is limited due to methodological limitations. To better assess the value of non-pharmacological interventions for this population, we recommend: (1) adoption of universal criteria for "early stage cognitive decline" among studies, (2) adherence to guidelines for the conceptualization, operationalization, and implementation of complex interventions, (3) consistent characterization of the impact of interventions on daily life, and (4) long-term follow-up of clinical outcomes to assess maintenance and meaningfulness of reported effects over time.

Computer-adaptive balance testing improves discrimination between community-dwelling elderly fallers and nonfallers

OBJECTIVES

To build an item response theory-based computer adaptive test (CAT) for balance from 3 traditional, fixed-form balance measures: Berg Balance Scale (BBS), Performance-Oriented Mobility Assessment (POMA), and dynamic gait index (DGI); and to examine whether the CAT's psychometric performance exceeded that of individual measures.

DESIGN

Secondary analysis combining 2 existing datasets.

SETTING

Community based.

PARTICIPANTS

Community-dwelling older adults (N=187) who were aged ≥65 years (mean age, 75.2±6.8y, 69% women).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The BBS, POMA, and DGI items were compiled into an initial 38-item bank. The Rasch partial credit model was used for final item bank calibration. CAT simulations were conducted to identify the ideal CAT. CAT score accuracy, reliability, floor and ceiling effects, and validity were examined. Floor and ceiling effects and validity of the CAT and individual measures were compared.

RESULTS

A 23-item bank met model expectations. A 10-item CAT was selected, showing a very strong association with full item bank scores (r=.97) and good overall reliability (.78). Reliability was better in low- to midbalance ranges as a result of better item targeting to balance ability when compared with the highest balance ranges. No floor effect was noted. The CAT ceiling effect (11.2%) was significantly lower than the POMA (40.1%) and DGI (40.3%) ceiling effects (P<.001 per comparison). The CAT outperformed individual measures, being the only test to discriminate between fallers and nonfallers (P=.007), and being the strongest predictor of self-reported function.

CONCLUSIONS

The balance CAT showed excellent accuracy, good overall reliability, and excellent validity compared with individual measures, being the only measure to discriminate between fallers and nonfallers. Prospective examination, particularly in low-functioning older adults and clinical populations with balance deficits, is recommended. Development of an improved CAT based on an expanded item bank containing higher difficulty items is also recommended.

Conceptual limitations of balance measures for community-dwelling older adults

BACKGROUND

Psychometric limitations of balance measures for community-dwelling elderly may be related to gaps in task and environmental representation.

OBJECTIVE

The purposes of this study were: (1) to conduct item-level content analysis of balance measures for community-dwelling elderly people based on task and environmental factors and (2) to develop profiles of individual measures summarizing their task and environment representation.

DESIGN

A systematic content analysis was conducted.

METHODS

A literature search was conducted to identify balance measures. Item-level content analysis was based on 7 criteria related to task and environment: (1) task role, (2) environmental variation, (3) object interaction, (4) obstacle negotiation, (5) external forces, (6) dual-tasking, and (7) moving people or objects in the environment.

RESULTS

Twenty-six measures, containing 167 items, were identified. Task role was fairly evenly distributed, with the majority of items examining gait tasks (32.3%), followed by dynamic body stability (29.9%) and static body stability (25.1%). The majority of items involved no environmental variation (58.1%), followed by variation of support surfaces (20.4%), visual conditions (13.2%), and both support and visual conditions (8.4%). Limited task role variability was seen within measures, with 73.1% of measures examining only one task role. Environmental variation was present in 65.3% of measures, primarily during static body stability tasks. Few measures involved object interaction (23.1%), obstacle negotiation (38.5%), external forces (11.5%), dual-tasking (7.7%), or moving people or objects (0%).

LIMITATIONS

The classification framework was not externally validated.

CONCLUSIONS

Existing measures focus on single-task assessment in static environments, underrepresenting postural control demands in daily-life situations involving dynamic changing environments, person-environment interactions, and multitasking. New items better reflecting postural control demands in daily-life situations are needed for more ecologically valid balance assessment. Individual balance measure profiles provided can help identify the most appropriate measure for a given purpose.

Quality of life in sarcopenia and frailty

The reduced muscle mass and impaired muscle performance that define sarcopenia in older individuals are associated with increased risk of physical limitation and a variety of chronic diseases. They may also contribute to clinical frailty. A gradual erosion of quality of life (QoL) has been evidenced in these individuals, although much of this research has been done using generic QoL instruments, particularly the SF-36, which may not be ideal in older populations with significant comorbidities. This review and report of an expert meeting presents the current definitions of these geriatric syndromes (sarcopenia and frailty). It then briefly summarizes QoL concepts and specificities in older populations and examines the relevant domains of QoL and what is known concerning QoL decline with these conditions. It calls for a clearer definition of the construct of disability, argues that a disease-specific QoL instrument for sarcopenia/frailty would be an asset for future research, and discusses whether there are available and validated components that could be used to this end and whether the psychometric properties of these instruments are sufficiently tested. It calls also for an approach using utility weighting to provide some cost estimates and suggests that a time trade-off study could be appropriate.