Study design, setting, and sample
A non-equivalent, controlled, pre-, post-, and follow-up test design was employed to identify the effectiveness of the multicomponent interventions for pre-frail or frail older adults of low SES who live alone. The study comprised a 12-week intervention and a 12-week follow-up period from May to November 2019. Samples for this study were selected from those who were enrolled in a public health center as a candidate for home-visiting nursing services, in a city near the capital city of Seoul, Korea. The services primarily focus on socioeconomically vulnerable populations, thus low SES prefrail or frail older adults in the community were considered as the candidates of this study.
Potential participants were identified through community screening. Eligible participants were (1) aged 65 years or older, (2) living alone, and (3) classified as pre-frail or frail. Potential participants were approached by a trained research assistant and informed about the purpose of the research and its voluntary nature. Upon providing written informed consent, each participant underwent a baseline assessment. Frailty was screened using a comprehensive geriatric assessment questionnaire used in the Visiting Health Management Services of the Korean Ministry of Health and Welfare [12]. It consists of self-reported questionnaires and objective measures of complex mobility function. Self-reported items included questions about daily activities of living (five items: ability to use public transport, shop for small purchases, visit the bank, venture out, and attend counseling), mobility (five items: climbing stairs, standing from a chair, walking for 15 min, history of falling, and fear of falling), nutritional status (five items: weight loss and body mass index, chewing or swallowing difficulties, and having a dry mouth), social activity (two items: number of outings per week and the frequency compared to the previous year), cognitive function (three items: forgetfulness, ability to make phone calls, and ability to recall past events), mood (five items), sensory function (one item: vision and hearing), and comorbidity. This information was collected through personal interviews conducted by a trained research assistant. The complex mobility function was measured using TUG. Frailty levels were calculated based on the scoring guidelines. Two points were assigned to the presence of any comorbidity, and an abnormal TUG; one point was assigned to a negative answer to the other items, yielding a maximum possible score of 31. Individuals were classified as robust if the frailty score was 0–3, pre-frail for scores 4–12, and frail for scores 13–31. Based on these criteria, those with scores of 4 or more were included in this study [12].
The group assignment was based on the waiting list for home-visiting nursing services in the public center. According to the waiting list order, first the experimental group was assigned, and then the control group. A priori computation of sample size using G* Power version 3.1 revealed that 56 participants were required with an effect size (f) of 0.2, an alpha value of 0.05, and an actual power of 0.90. A total of 138 participants completed the initial assessments (Fig. 1). Among them, eight participants failed to meet the inclusion criteria (frailty score < 4), so 130 participants were assigned to the experimental (n=66) or the control (n=64) group. Four participants in the experimental group withdrew from the study. Therefore, the final sample of 126 participants (62 in the experimental and 64 in the control group) was analyzed in this study.
Intervention
The 12-week multicomponent intervention for the experimental group was composed of exercise, cognitive training, and education for nutrition and disease management based on the multidimentional concept of frailty [2]. The intervention was conducted in accessible, attractive, and safe places, such as public health centers or senior centers to reduce the attrition rate. The intervention consisted of two 40-minute sessions once a week for 12 weeks. The first was a 40-minute group exercise session administered to approximately 10–15 participants by an exercise coach and trained exercise assistants. Each exercise session consisted of stretching (5 min), resistance exercises with elastic TheraBands (20 min), and aerobic movements (15 min) on rhythmic music selected by the participants to ensure a fun session. The intensity of the exercise was adjusted to suit the prefrail or frail elderly to reduce the follow-up loss. Each participant was trained for every activity according to their competence, allowing them to track their own exercise. They were closely monitored by the exercise coach and her assistants to prevent any injury. Resistance exercises focused on both the upper and lower extremities, emphasizing on muscles that are important for balance and gait control to prevent falls. The aerobic portion included stepping in standing positions or while sitting in a chair, as well as standing up from and sitting in a chair. Educational leaflets for each movement were distributed so that the participants could exercise at home even on days when they did not participate in the exercise class.
After the first exercise session, cognitive training session continued for another 40 min. The second session included either calendar making or Cup Nanta, alternatively every other week, to improve cognitive function and sociality. These facilitated reminiscence and attention through art activities and folk music performances. The calendar-making program was operated using various materials; participants were encouraged to draw fun memories or special events of each month individually, and seasonal landscapes. The calendars were decorated with various, easily accessible materials, such as aluminum foil, old clothes, dried grains, coarse salt, cotton ball, etc. This process not only enabled the participants to reminisce about their meaningful everyday lives but also, and more crucially, helped them fulfill a desire for education that may have remained unfulfilled during their childhood. It simultaneously enhanced their concentration and sense of accomplishment.
Cup Nanta, a performance involving tapping cups on a desk according to a rhythm to achieve harmony, is designed to strengthen the fingers as well as to improve sociality and emotional bonds among the participants. The meticulous efforts taken by each member to produce a unified performance, by aligning the sequence and rhythm of each movement, and prevent errors, enhanced the overall performance.
Health education regarding nutrition and chronic disease management was provided once per month. Nutrition education or cooking classes focused on selecting healthy foods and convenient recipes. Physicians enhanced medication adherence and healthy lifestyle choices to the participants. They provided health education on therapeutic goals for managing chronic disease, blood glucose, blood pressure and self-management skills. In addition, therapeutic connections were formed between the participants and the medical doctors practicing in the participants’ area of residence for direct treatment and consultation, to enable continuous treatment and monitoring after the program intervention. Healthy snacks were provided to reduce the risk of attrition. To ensure the validity of the study’s results, the researchers who collected and analyzed the data did not participate in the program. They were blinded to the participants’ group assignments.
Measures
Measures for the following outcome variables were completed three times: at pre-intervention, post-intervention, and at the 12-week follow-up.
Frailty
We used 28-item frailty index to evaluate the effect of the intervention in this study [12]. It contains questions (containing five items each) regarding instrumental activities of daily living, physical functioning, nutritional status, and cognitive functioning. Participants were asked to answer yes or no to each question. Subsequently, the scores for all items were summed to indicate the level of frailty. Possible scores range from 0 to 31, with higher scores indicating a higher likelihood of frailty.
Timed Up and Go test (TUG)
The complex mobility function was measured using TUG. Participants were asked to stand up from a standard armchair, walk 3 m straight, turn around, walk back, and sit down on the chair. The time from getting up from the seat to sitting again was measured in seconds.
Handgrip strength
The handgrip strength of the dominant hand was measured with a dynamometer (Tabita 6103) with participants standing upright, facing forward, with elbows fully extended and their feet shoulder-width apart. For each of the three measurement points (pre-intervention, post-intervention, and at follow-up), handgrip strength was measured in kilograms twice, with a one-minute interval, and the scores were averaged for the analyses.
Depression
The 15-item Geriatric Depression Scale-Short Form Korean Version (GDSSF-K) measured depression [21, 22]. Participants were asked to rate their mood status on a yes or no scale. The level of depression was expressed as the average of all item scores, ranging from 0 to 15. Higher scores represented a greater level of depressive mood. The reliability coefficient of the GDSSF-K in Kee’s study was 0.88 [22], and 0.92 in this study.
Social activity
A five-item social activity scale developed in a sample of Korean older women living alone [23] was used to assess the levels of social activity in this study. Participants were asked to rate the frequency of their social activity for particular purposes, such as friend gatherings and economic or religious activities, on a scale of 0 (not at all) to 5 (every day). Total scores were calculated by averaging item scores, with higher scores indicating a greater frequency of social activities. Cronbach’s alpha was 0.89 in the present study.
Social support
The 19-item Medical Outcomes Study Social Support Scale was used to measure the level of social support on a five-point Likert scale [24]. The total social support score was calculated based on the scoring guidelines, ranging from 0 to 100. Higher scores indicate higher levels of social support. The scale was found to have good internal reliability at the time of its development. In this study, the internal reliability was 0.94.
Statistical analysis
Data were analyzed using IBM SPSS software (version 23.0; IBM Corp., Armonk, NY, USA). The variables were screened for potential errors, missing data, and outliers. Assumptions were checked for every statistical analysis. Descriptive statistics were calculated for all variables. Bivariate analyses (i.e., t-tests, chi-square tests, and Fisher’s exact test) were conducted to examine the homogeneity between the two groups. To evaluate the effect of the intervention over time, a mixed ANOVA (repeated measures) was used to compare the differences between the outcome measures of the two groups. Partial eta-squared values were presented as a measure of effect size. A value of 0.01 indicates a small effect size, 0.06 indicates a moderate effect size, and 0.14 indicates a large effect size [25]. Differences were considered statistically significant at p < 0.05.