Effect of a Multifactorial Fall Injury Prevention Intervention on Patient Well-Being: The STRIDE Study

A pilot study to identify factors associated with frailty within the World Trade Center general responder cohort

BACKGROUND

Given the significant exposures experienced by the World Trade Center (WTC) general responders, there is increasing interest in understanding the effect of these exposures on aging in this population. We aim to identify factors that may be associated with frailty, a clinical syndrome characterized by a decrease in one's reserve that has been linked to poor health outcomes.

METHODS

WTC general responders enrolled in the WTC Health Program aged 50 and older provided informed consent. Validated frailty assessments, the Frailty Phenotype (with the Johns Hopkins Frailty Assessment Calculator) along with the FRAIL scale, categorized nonfrail from prefrail/frail. Fall risk, functional status, and cognition were also assessed. WTC variables, including an identified WTC-certified condition, were utilized. The risk of frailty was estimated using log binomial regression analysis. A 95% confidence interval (CI) was used to estimate the prevalence ratio (PR).

RESULTS

One hundred and six participants were included; 38 (35.8%) were classified as pre-frail or frail. More of the pre-frail/frail group were obese (57.9% vs. 25%; p = 0.004) and had a WTC-certified condition (78.9% vs. 58.8%; p = 0.036). Obesity (PR = 2.43, 95% CI = 1.31, 4.53), a WTC-certified condition (PR = 1.77, 95% CI = 1.09, 2.89), and risk of falling (PR = 1.97, 95% CI = 1.01, 3.84) were independently associated with frailty.

CONCLUSIONS

Obesity and having a WTC-certified condition were found to be risk factors for frailty in our pilot study. Future work may focus on further identifying risk factors for frailty in the larger WTC general responder population.

Validation of a Rule-Based ICD-10-CM Algorithm to Detect Fall Injuries in Medicare Data

BACKGROUND

Diagnosis-code-based algorithms to identify fall injuries in Medicare data are useful for ascertaining outcomes in interventional and observational studies. However, these algorithms have not been validated against a fully external reference standard, in ICD-10-CM, or in Medicare Advantage (MA) data.

METHODS

We linked self-reported fall injuries leading to medical attention (FIMA) from the Strategies to Reduce Injuries and Develop Confidence in Elders (STRIDE) trial (reference standard) to Medicare fee-for-service (FFS) and MA data from 2015-19. We measured the area under the receiver operating characteristic curve (AUC) based on sensitivity and specificity of a diagnosis-code-based algorithm against the reference standard for presence or absence of ≥1 FIMA within a specified window of dates, varying the window size to obtain points on the curve. We stratified results by source (FFS vs MA), trial arm (intervention vs control), and STRIDE's 10 participating health care systems.

RESULTS

Both reference standard data and Medicare data were available for 4 941 (of 5 451) participants. The reference standard and algorithm identified 2 054 and 2 067 FIMA, respectively. The algorithm had 45% sensitivity (95% confidence interval [CI]: 43%-47%) and 99% specificity (95% CI: 99%-99%) to identify reference standard FIMA within the same calendar month. The AUC was 0.79 (95% CI: 0.78-0.81) and was similar by FFS or MA data source and by trial arm but showed variation among STRIDE health care systems (AUC range by health care system, 0.71 to 0.84).

CONCLUSIONS

An ICD-10-CM algorithm to identify fall injuries demonstrated acceptable performance against an external reference standard, in both MA and FFS data.

Medicare's Hospital Readmission Reduction Program reduced fall-related health care use: An unexpected benefit?

OBJECTIVE

To assess whether Medicare's Hospital Readmissions Reduction Program (HRRP) was associated with a reduction in severe fall-related injuries (FRIs).

DATA SOURCES AND STUDY SETTING

Secondary data from Medicare were used.

STUDY DESIGN

Using an event study design, among older (≥65) Medicare fee-for-service beneficiaries, we assessed changes in 30- and 90-day FRI readmissions before and after HRRP's announcement (April 2010) and implementation (October 2012) for conditions targeted by the HRRP (acute myocardial infarction [AMI], congestive heart failure [CHF], and pneumonia) versus "non-targeted" (gastrointestinal) conditions. We tested for modification by hospitals with "high-risk" before HRRP and accounted for potential upcoding. We also explored changes in 30-day FRI readmissions involving emergency department (ED) or outpatient care, care processes (length of stay, discharge destination, and primary care visit), and patient selection (age and comorbidities).

DATA COLLECTION

Not applicable.

PRINCIPAL FINDINGS

We identified 1.5 million (522,596 pre-HRRP, 514,844 announcement, and 474,029 implementation period) index discharges. After its announcement, HRRP was associated with 12%-20% reductions in 30- and 90-day FRI readmissions for patients with CHF (-0.42 percentage points [ppt], p = 0.02; -1.53 ppt, p < 0.001) and AMI (-0.35, p = 0.047; -0.97, p = 0.001). Two years after implementation, HRRP was associated with reductions in 90-day FRI readmission for AMI (-1.27 ppt, p = 0.01) and CHF (-0.98 ppt, p = 0.02) patients. Results were similar for hospitals at higher versus lower baseline risk of FRI readmission. After HRRP's announcement, decreases were observed in home health (AMI: -2.43 ppt, p < 0.001; CHF: -8.83 ppt, p < 0.001; pneumonia: -1.97 ppt, p < 0.001) and skilled nursing facility referrals (AMI: -5.95 ppt, p < 0.001; CHF: -3.19 ppt, p < 0.001; pneumonia: -10.27 ppt, p < 0.001).

CONCLUSIONS

HRRP was associated with reductions in FRIs, primarily for HF and pneumonia patients. These decreases may reflect improvements in transitional care including changes in post-acute referral patterns that benefit patients at risk for falls.

Cognitive behavioural therapy (CBT) with and without exercise to reduce fear of falling in older people living in the community

BACKGROUND

Fear of falling (FoF) is a lasting concern about falling that leads to an individual avoiding activities that he/she remains capable of performing. It is a common condition amongst older adults and may occur independently of previous falls. Cognitive behavioural therapy (CBT), a talking therapy that helps change dysfunctional thoughts and behaviour, with and without exercise, may reduce FoF, for example, by reducing catastrophic thoughts related to falls, and modifying dysfunctional behaviour.

OBJECTIVES

To assess the benefits and harms of CBT for reducing FoF in older people living in the community, and to assess the effects of interventions where CBT is used in combination with exercise.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 1, 2023), MEDLINE Ovid (from 1946 to 11 January 2023), Embase Ovid (from 1980 to 11 January 2023), CINAHL Plus (Cumulative Index to Nursing and Allied Health Literature) (from 1982 to 11 January 2023), PsycINFO (from 1967 to 11 January 2023), and AMED (Allied and Complementary Medicine from 1985 to 11 January 2023). We handsearched reference lists and consulted experts for identifying additional studies.

SELECTION CRITERIA

This review included randomised controlled trials (RCTs), quasi-RCTs, and cluster-RCTs assessing CBT with and without exercise interventions compared to control groups with sham-treatment, or treatment as usual. We defined CBT as a collaborative, time-limited, goal-oriented, and structured form of speaking therapy. Included studies recruited community-dwelling older adults, with a mean population age of at least 60 years minus one standard deviation, and not defined by a specific medical condition.

DATA COLLECTION AND ANALYSIS

Two review authors used standard methodological procedures expected by Cochrane. For continuous data, as assessed by single- or multiple-item questionnaires, we report the mean difference (MD) with 95% confidence interval (CI) when studies used the same outcome measures, and standardised mean difference (SMD) when studies used different measures for the same clinical outcome. For dichotomous outcomes, we reported the treatment effects as risk ratios (RR) with 95% CIs. We measured the primary outcome, FoF, immediately, up to, and more than six months after the intervention. We analysed secondary outcomes of activity avoidance, occurrence of falls, depression, and quality of life when measured immediately after the intervention. We assessed risk of bias for each included study, using the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We selected 12 studies for this review, with 11 studies included for quantitative synthesis. One study could not be included due to missing information. Of the 11 individual studies, two studies provided two comparisons, which resulted in 13 comparisons. Eight studies were RCTs, and four studies were cluster-RCTs. Two studies had multiple arms (CBT only and CBT with exercise) that fulfilled the inclusion criteria. The primary aim of 10 studies was to reduce FoF. The 11 included studies for quantitative synthesis involved 2357 participants, with mean ages between 73 and 83 years. Study total sample sizes varied from 42 to 540 participants. Of the 13 comparisons, three investigated CBT-only interventions while 10 investigated CBT with exercise. Intervention duration varied between six and 156 hours, at a frequency between three times a week and monthly over an eight- to 48-week period. Most interventions were delivered in groups of between five and 10 participants, and, in one study, up to 25 participants. Included studies had considerable heterogeneity, used different questionnaires, and had high risks of bias. CBT interventions with and without exercise probably improve FoF immediately after the intervention (SMD -0.23, 95% CI -0.36 to -0.11; 11 studies, 2357 participants; moderate-certainty evidence). The sensitivity analyses did not change the intervention effect significantly. Effects of CBT with or without exercise on FoF may be sustained up to six months after the intervention (SMD -0.24, 95% CI -0.41 to -0.07; 8 studies, 1784 participants; very low-certainty evidence). CBT with or without exercise interventions for FoF probably sustains improvements beyond six months (SMD -0.28, 95% CI -0.40 to -0.15; 5 studies, 1185 participants; moderate-certainty of evidence). CBT interventions for reducing FoF may reduce activity avoidance (MD -2.57, 95% CI -4.67 to -0.47; 1 study, 312 participants; low-certainty evidence), and level of depression (SMD -0.41, 95% CI -0.60 to -0.21; 2 studies, 404 participants; low-certainty evidence). We are uncertain whether CBT interventions reduce the occurrence of falls (RR 0.96, 95% CI 0.66 to 1.39; 5 studies, 1119 participants; very low-certainty evidence). All studies had a serious risk of bias, due to performance bias, and at least an unclear risk of detection bias, as participants and assessors could not be blinded due to the nature of the intervention. Downgrading of certainty of evidence also occurred due to heterogeneity between studies, and imprecision, owing to limited sample size of some studies. There was no reporting bias suspected for any article. No studies reported adverse effects due to their interventions.

AUTHORS' CONCLUSIONS

CBT with and without exercise interventions probably reduces FoF in older people living in the community immediately after the intervention (moderate-certainty evidence). The improvements may be sustained during the period up to six months after intervention (low-certainty evidence), and probably are sustained beyond six months (moderate-certainty evidence). Further studies are needed to improve the certainty of evidence for sustainability of FoF effects up to six months. Of the secondary outcomes, we are uncertain whether CBT interventions for FoF reduce the occurrence of falls (very low-certainty evidence). However, CBT interventions for reducing FoF may reduce the level of activity avoidance, and may reduce depression (low-certainty evidence). No studies reported adverse effects. Future studies could investigate different populations (e.g. nursing home residents or people with comorbidities), intervention characteristics (e.g. duration), or comparisons (e.g. CBT versus exercise), investigate adverse effects of the interventions, and add outcomes (e.g. gait analysis). Future systematic reviews could search specifically for secondary outcomes.

Designing three-level cluster randomized trials to assess treatment effect heterogeneity

Cluster randomized trials often exhibit a three-level structure with participants nested in subclusters such as health care providers, and subclusters nested in clusters such as clinics. While the average treatment effect has been the primary focus in planning three-level randomized trials, interest is growing in understanding whether the treatment effect varies among prespecified patient subpopulations, such as those defined by demographics or baseline clinical characteristics. In this article, we derive novel analytical design formulas based on the asymptotic covariance matrix for powering confirmatory analyses of treatment effect heterogeneity in three-level trials, that are broadly applicable to the evaluation of cluster-level, subcluster-level, and participant-level effect modifiers and to designs where randomization can be carried out at any level. We characterize a nested exchangeable correlation structure for both the effect modifier and the outcome conditional on the effect modifier, and generate new insights from a study design perspective for conducting analyses of treatment effect heterogeneity based on a linear mixed analysis of covariance model. A simulation study is conducted to validate our new methods and two real-world trial examples are used for illustrations.

Costs of fall injuries in the STRIDE study: an economic evaluation of healthcare system heterogeneity and heterogeneity of treatment effect

OBJECTIVES

The Strategies to Reduce Injuries and Develop Confidence in Elders (STRIDE) Study cluster-randomized 86 primary care practices in 10 healthcare systems to a patient-centered multifactorial fall injury prevention intervention or enhanced usual care, enrolling 5451 participants. We estimated total healthcare costs from participant-reported fall injuries receiving medical attention (FIMA) that were averted by the STRIDE intervention and tested for healthcare-system-level heterogeneity and heterogeneity of treatment effect (HTE).

METHODS

Participants were community-dwelling adults age ≥ 70 at increased fall injury risk. We estimated practice-level total costs per person-year of follow-up (PYF), assigning unit costs to FIMA with and without an overnight hospital stay. Using independent variables for treatment arm, healthcare system, and their interaction, we fit a generalized linear model with log link, log follow-up time offset, and Tweedie error distribution.

RESULTS

Unadjusted total costs per PYF were $2,034 (intervention) and $2,289 (control). The adjusted (intervention minus control) cost difference per PYF was -$167 (95% confidence interval (CI), -$491, $216). Cost heterogeneity by healthcare system was present (p = 0.035), as well as HTE (p = 0.090). Adjusted total costs per PYF in control practices varied from $1,529 to $3,684 for individual healthcare systems; one system with mean intervention minus control costs of -$2092 (95% CI, -$3,686 to -$944) per PYF accounted for HTE, but not healthcare system cost heterogeneity.

CONCLUSIONS

We observed substantial heterogeneity of healthcare system costs in the STRIDE study, with small reductions in healthcare costs for FIMA in the STRIDE intervention accounted for by a single healthcare system.

TRIAL REGISTRATION

Clinicaltrials.gov (NCT02475850).

Effects of case management based on preventing falls in older people: A systematic review

BACKGROUND

Falls among older adults can lead to negative consequences with physical, functional, social, and psychological functioning, and a high prevalence of mortality. However, it is still unclear whether case management can reduce the number of falls in this population.

AIMS

The aims of this review were to analyze the effects of case management on preventing falls and reducing risk factors for falls in older people.

METHODS

A systematic review was conducted, searching for and synthesizing clinical trials involving case management in older people who had falls or risk for fall outcomes. Two authors extracted data using predefined data fields, and risk of bias was assessed by the Physiotherapy Evidence Database (PEDro) scale.

RESULTS

Twelve studies were included in the final review. Case management in older people did not significantly reduce the number of falls, falls per person, or severity of falls compared to control groups. Adherence to recommendations in case management ranged from 25% to 88%.

LINKING EVIDENCE TO ACTION

There is limited evidence of reduced rates of falls and specific risk factors for falls among people who received case management interventions. Randomized trials with good quality are needed.

Potential Solutions for the Mitigation of Hip Injuries Caused by Falls in Older Adults: A Narrative Review

BACKGROUND

Hip injuries caused by falling are common and often catastrophic for older adults. There is thus an urgent need to develop solutions designed to mitigate fall injuries to the hip by reducing the forces created on the body by ground impact.

METHODS

The goal of this narrative review was to synthesize published literature on available products developed with the expressed goal of reducing fall-related hip injuries.

RESULTS

Three categories were identified: passive wearables (eg, hip protectors), active wearables (eg, instrumented belts with deployable airbags), and compliant flooring. Laboratory studies indicate that each technology can reduce peak forces induced by simulated falls. Considerable preliminary data suggest that passive wearables and compliant flooring may reduce fall-related injuries within long-term care facilities. Controlled trials of specific types of these 2 technologies, however, have produced inconsistent results. While little is known about the effectiveness of active wearables, promising early data indicate the feasibility of an instrumented belt worn around the waist to effectively deploy an airbag to protect the hips prior to ground impact. Important challenges associated with one or more identified technologies included poor adherence to instructed wear as well as the potential for significant physical or time burden to caregivers or health care professionals.

CONCLUSIONS

Passive wearables, active wearables, and compliant flooring have shown promise in reducing fall-related hip injuries in older adults. Still, each type of product is accompanied by limited real-world data and/or significant challenges that must be overcome to maximize effectiveness and minimize unintended side effects.

Effect of a Home Health and Safety Intervention on Emergency Department Use in the Frail Elderly: A Prospective Observational Study

INTRODUCTION

Geriatric patients are often frail and may lose independence through a variety of mechanisms including cognitive decline, reduced mobility, and falls. Our goal was to measure the effect of a multidisciplinary home health program that assessed frailty and safety and then coordinated ongoing delivery of community resources on short-term, all-cause emergency department (ED) utilization across three study arms that attempted to stratify frailty by fall risk.

METHODS

Subjects became eligible for this prospective observational study via one of three pathways: 1) by visiting the ED after a fall (2,757 patients); 2) by self-identifying as at risk for falling (2,787); or 3) by calling 9-1-1 for a "lift assist" after falling and being unable to get up (121). The intervention consisted of sequential home visits by a research paramedic who used standardized assessments of frailty and risk of falling (including providing home safety guidance), and a home health nurse who aligned resources to address the conditions found. Outcomes of interest were all-cause ED utilization at 30, 60, and 90 days post-intervention compared with subjects who enrolled via the same study pathway but declined the study intervention (controls).

RESULTS

Subjects in the fall-related ED visit arm were significantly less likely to have one or more subsequent ED encounters post-intervention than controls at 30 days (18.2% vs 29.2%, P<0.001); 60 days (27.5% vs 39.8%, P<0.001); and 90 days (34.6% vs 46.2%, P<0.001). In contrast, participants in the self-referral arm had no difference in ED encounters post-intervention compared to controls at 30, 60, or 90 days (P=0.30, 0.84, and 0.23, respectively). The size of the 9-1-1 call arm limited statistical power for analysis.

CONCLUSION

A history of a fall requiring ED evaluation appeared to be a useful marker of frailty. Subjects recruited through this pathway experienced less all-cause ED utilization over subsequent months after a coordinated community intervention than without it. The participants who only self-identified as at risk for falling had lower rates of subsequent ED utilization than those recruited in the ED after a fall and did not significantly benefit from the intervention.

Engagement of older adults in STRIDE's multifactorial fall injury prevention intervention

BACKGROUND

Evidence-based multifactorial fall prevention interventions in clinical practice have been less effective than expected. One plausible reason is that older adults' engagement in fall prevention care is suboptimal.

METHODS

This was a post-hoc analysis of 2403 older adults' engagement in a multifactorial fall prevention intervention in the Strategies to Reduce Injuries and Develop Confidence in Elders (STRIDE) pragmatic trial. Based on the direct clinical care level of the Patient and Family Continuum of Engagement (CE) framework, three indicators of progressively interactive engagement were assessed: (1) Consultation (receiving information), (2) Involvement (prioritizing risks), and (3) Partnership (identifying prevention actions). Drop off at each step was determined as well as predictors of engagement.

RESULTS

The participants' engagement waned with increasingly interactive CE domains. Although all participants received information about their positive fall risk factors (consultation) and most (51%-96%) prioritized them (involvement), fewer participants (33%-55%) identified fall prevention actions (partnership) for most of their risk factors, except for strength gait or balance problems (95%). More participants (70%) identified home exercises than other actions. Finally, fall prevention actions were identified more commonly among participants who received two visits compared to one (OR = 2.33 [95% CI, 2.06-2.64]), were ≥80 years old (OR = 1.83 [95% CI, 1.51-2.23]), and had fewer fall risk factors (OR = 0.90 [95% CI, 0.83-0.99]).

CONCLUSIONS

The drop-off in participants' engagement based on the level of their interaction with clinicians suggests that future multifactorial fall prevention interventions need to be more focused on interactive patient-clinician partnerships that help older adults increase and maintain fall prevention actions. Our analyses suggest that more frequent contact with clinicians and more monitoring of the implementation and outcomes of Fall Prevention Care Plans could potentially improve engagement and help older adults maintain fall prevention actions.

Effect of the STRIDE fall injury prevention intervention on falls, fall injuries, and health-related quality of life

BACKGROUND

Falls are common in older adults and can lead to severe injuries. The Strategies to Reduce Injuries and Develop Confidence in Elders (STRIDE) trial cluster-randomized 86 primary care practices across 10 health systems to a multifactorial intervention to prevent fall injuries, delivered by registered nurses trained as falls care managers, or enhanced usual care. STRIDE enrolled 5451 community-dwelling older adults age ≥70 at increased fall injury risk.

METHODS

We assessed fall-related outcomes via telephone interviews of participants (or proxies) every 4 months. At baseline, 12 and 24 months, we assessed health-related quality of life (HRQOL) using the EQ-5D-5L and EQ-VAS. We used Poisson models to assess intervention effects on falls, fall-related fractures, fall injuries leading to hospital admission, and fall injuries leading to medical attention. We used hierarchical longitudinal linear models to assess HRQOL.

RESULTS

For recurrent event models, intervention versus control incidence rate ratios were 0.97 (95% confidence interval [CI], 0.93-1.00; p = 0.048) for falls, 0.93 (95% CI, 0.80-1.08; p = 0.337) for self-reported fractures, 0.89 (95% CI, 0.73-1.07; p = 0.205) for adjudicated fractures, 0.91 (95% CI, 0.77-1.07; p = 0.263) for falls leading to hospital admission, and 0.97 (95% CI, 0.89-1.06; p = 0.477) for falls leading to medical attention. Similar effect sizes (non-significant) were obtained for dichotomous outcomes (e.g., participants with ≥1 events). The difference in least square mean change over time in EQ-5D-5L (intervention minus control) was 0.009 (95% CI, -0.002 to 0.019; p = 0.106) at 12 months and 0.005 (95% CI, -0.006 to 0.015; p = 0.384) at 24 months.

CONCLUSIONS

Across a standard set of outcomes typically reported in fall prevention studies, we observed modest improvements, one of which was statistically significant. Future work should focus on patient-, practice-, and organization-level operational strategies to increase the real-world effectiveness of interventions, and improving the ability to detect small but potentially meaningful clinical effects.

CLINICALTRIALS

gov identifier: NCT02475850.

Extended effects of a wearable sensory prosthesis on gait, balance function and falls after 26 weeks of use in persons with peripheral neuropathy and high fall risk—The walk2Wellness trial

Background

We recently reported that individuals with impaired plantar sensation and high fall risk due to sensory peripheral neuropathy (PN) improved gait and balance function following 10 weeks of use of Walkasins^®, a wearable lower limb sensory prosthesis that provides directional specific mechanical tactile stimuli related to plantar pressure measurements during standing and walking (RxFunction Inc., Eden Prairie, MN, United States). Here, we report 26-week outcomes and compare pre- and in-study fall rates. We expected improvements in outcomes and reduced fall rates reported after 10 weeks of use to be sustained.

Materials and methods

Participants had clinically diagnosed PN with impaired plantar sensation, high fall risk (Functional Gait Assessment, FGA score < 23) and ability to sense tactile stimuli above the ankle at the location of the device. Additional outcomes included 10 m Gait Speed, Timed Up and Go (TUG), Four-Stage Balance Test, and self-reported outcomes, including Activities-Specific Balance Confidence scale and Vestibular Disorders Activities of Daily Living Scale. Participants tracked falls using a calendar.

Results

We assessed falls and self-reported outcomes from 44 individuals after 26 weeks of device use; 30 of them conducted in-person testing of clinical outcomes. Overall, improvements in clinical outcomes seen at 10 weeks of use remained sustained at 26 weeks with statistically significant increases compared to baseline seen in FGA scores (from 15.0 to 19.2), self-selected gait speed (from 0.89 to 0.97 m/s), and 4-Stage Balance Test (from 25.6 to 28.4 s), indicating a decrease in fall risk. Non-significant improvements were observed in TUG and fast gait speed. Overall, 39 falls were reported; 31 of them did not require medical treatment and four caused severe injury. Participants who reported falls over 6 months prior to the study had a 43% decrease in fall rate during the study as compared to self-report 6-month pre-study (11.8 vs. 6.7 falls/1000 patient days, respectively, p < 0.004), similar to the 46% decrease reported after 10 weeks of use.

Conclusion

A wearable sensory prosthesis can improve outcomes of gait and balance function and substantially decreases incidence of falls during long-term use. The sustained long-term benefits in clinical outcomes reported here lessen the likelihood that improvements are placebo effects.

Clinical trial registration

ClinicalTrials.gov, identifier #NCT03538756.

A Matched Cohort Analysis for Examining the Association Between Slow Gait Speed and Shortened Longevity in Older Americans

This investigation examined the association between slow gait speed, as defined with newly established cut-points, and all-cause mortality in older Americans with a matched cohort analysis. The analytic sample included 10,259 Americans aged ≥65 years from the 2006-2014 waves of the Health and Retirement Study. Walking speed was measured in participant residences. Slow gait speed cut-points of <0.60 and <0.75 m/s were used separately for classifying participants as having slow walking speed. Nearest-neighbor propensity score matching was used to match the slow to the not-slow cohorts separately using both cut-points using relevant covariates. Persons with gait speed <0.60 m/s had a 1.42 higher hazard for mortality (95% CI: 1.28-1.57). Older Americans with gait speed <0.75 m/s had a 1.36 higher hazard for mortality (95% CI: 1.23-1.50). Slow gait speed may represent failing health and addressing how slow gait speed could be improved may help with referrals to appropriate interventions.

Accounting for unequal cluster sizes in designing cluster randomized trials to detect treatment effect heterogeneity

Unequal cluster sizes are common in cluster randomized trials (CRTs). While there are a number of previous investigations studying the impact of unequal cluster sizes on the power for testing the average treatment effect in CRTs, little is known about the impact of unequal cluster sizes on the power for testing the heterogeneous treatment effect (HTE) in CRTs. In this work, we expand the sample size procedures for studying HTE in CRTs to accommodate cluster size variation under the linear mixed model framework. Through analytical derivation and graphical exploration, we show that the sample size for the HTE with an individual-level effect modifier is less affected by unequal cluster sizes than with a cluster-level effect modifier. The impact of cluster size variability jointly depends on the mean and coefficient of variation of cluster sizes, covariate intraclass correlation coefficient (ICC) and the conditional outcome ICC. In addition, we demonstrate that the HTE-motivated analysis of covariance framework can be used for analyzing the average treatment effect, and offer a more efficient sample size procedure for studying the average treatment effect adjusting for the effect modifier. We use simulations to confirm the accuracy of the proposed sample size procedures for both the average treatment effect and HTE in CRTs. Extensions to multivariate effect modifiers are provided and our procedure is illustrated in the context of the Strategies to Reduce Injuries and Develop Confidence in Elders trial.

Bibliometrics and Co-Citation Network Analysis of Systematic Reviews of Evidence-Based Nursing Guidelines for Preventing Inpatient Falls

Advances in bibliometrics and co-citation analysis provide the opportunity to analyze quantitatively the large amount of nursing research used in evidence-based nursing. Numerous nursing researchers have attempted to obtain evidence that using evidence-based nursing improves the quality of nursing practices. However, little is known about how these efforts comply with the rigorous methods required for a systematic review in a subject area. This study explored the comprehensiveness of systematic reviews in four guidelines for preventing inpatient falls using bibliometrics and a co-citation network technique. Citations (n = 659) and 9417 unique bibliographic records written by 6537 authors were collected from the guidelines in January 2020. The results showed none of the references spanned all four authoring bodies, whereas only 0.1% and 4.7% of the references spanned three and two of the authoring bodies, respectively. The co-citation analysis revealed differences in the scope and primary concerns among the development groups, even in the same setting, with differences in the highly influential articles and authors. These findings imply that although the systematic reviews of guidelines on fall prevention were of good quality, there remain areas for improvement in terms of harmonizing the selection of bibliographic citations comprehensively.