2023 Volume 8 Article ID: 20230028
Objectives: Little attention has been paid to the relationship between balance function and bathing independence. This research aimed to determine the degree of balance function needed by patients with stroke and patients with hip fracture (hereinafter referred to as patients with stroke and hip fracture) to bathe independently.
Methods: Retrospective data analysis was performed on 59 patients with hip fracture and 201 patients with stroke. Logistic regression was performed to determine whether bathing independence was associated with the Berg Balance Scale (BBS) in patients with stroke and hip fracture. A receiver operating characteristic curve was generated to calculate cutoff values.
Results: The BBS was significantly associated with bathing independence in patients with stroke and hip fracture. The calculated BBS cutoff value was 48 points for those with stroke (sensitivity, 84.7%; specificity, 79.1%) and 43 points for those with hip fracture (sensitivity, 81.3%; specificity, 77.8%).
Conclusions: Balance function was independently associated with bathing independence. The level of balance function required for bathing independence may be lower for patients with hip fracture than for those with stroke. This could be a simple and useful indicator for rehabilitation professionals to interpret BBS results when conducting bathing interventions.
Stroke and hip fracture are two of the major diseases that require rehabilitation. In 2019, 12.2 million incident cases of stroke and 14.2 million cases of hip fracture were reported.1,2) These numbers are unlikely to decline in the foreseeable future as the global population continues to age. Stroke and hip fractures have a substantial impact on the medium- to long-term disabilities of affected patients.3,4) For these individuals, rehabilitation is crucial to regaining the capacity to perform activities of daily living (ADLs).
Bathing is one of the most difficult ADLs to perform independently.5) Patients with stroke and those with hip fracture (hereinafter collectively referred to as patients with stroke and hip fracture) have difficulty with independent bathing even after rehabilitation.6,7) However, bathing is an important ADL that maintains physical cleanliness and relaxes the body and mind. Bathing has also been reported to improve subjective health and sleep quality, reduce the risk of cardiovascular disease, and decrease blood glucose and obesity.8,9,10) Bathing is a popular and often habitual pastime that is part of the Japanese culture.8)
Balance function has been closely associated with independence in ADL among patients with stroke and hip fracture.11,12) Reports have shown that around 83% of patients with stroke suffer from balance impairment, and good balance is a prerequisite for regaining the ability to perform ADLs independently.13) Balance impairment is the primary risk factor for falls in the elderly population, and falls are the most common cause of age-related hip fractures.14,15) Therefore, improving balance function is a key component of rehabilitation for patients with stroke and hip fracture.16,17)
Generally, little attention has been paid to the relationship between balance function and bathing independence. In particular, the level of balance function necessary for bathing independence has not been investigated to date and remains unclear. Clarifying the level of balance function required for bathing independence in patients with stroke and hip fracture will provide useful information for rehabilitation planning. This study aimed to determine the level of balance function required for bathing independence in patients with stroke and hip fracture. The results of this research are expected to be used to interpret balance assessment data and to guide balance training.
A retrospective observational research design was used for this study. The participants included 260 inpatients (201 with stroke and 59 with hip fracture) who were admitted to a convalescent rehabilitation ward in Japan and satisfied the following criteria. The inclusion criteria for patients with stroke were as follows: (1) those aged 20 years or older, (2) those with unilateral supratentorial lesions, (3) those diagnosed with a cerebral hemorrhage or infarction for the first time, (4) those admitted or discharged between April 2011 and December 2017. The inclusion criteria for patients with hip fracture were as follows (1) those admitted or discharged between April 2015 and March 2018, (2) those diagnosed with a femoral neck or trochanteric fracture, (3) those without a history of stroke, and (4) those aged 20 years or older. Patients with missing data were excluded. This study was approved by the Kita-Fukushima Medical Center and Fukushima Medical University’s ethics review committee (No. 94, general 2020–236). Because the design of our study was retrospective without intervention, the opt-out method was used instead of informed consent.
Instruments for Data CollectionInformation on age, gender, independence in bathing (including showering), and physical and mental functions (including balance function at discharge) were collected from the medical charts of the participants. Bathing was assessed using the Barthel Index,18) and a score of 5 points was defined as “independent” in this study. Assessment using the Barthel Index was performed by occupational therapists. The Berg Balance Scale (BBS)19) was used as an index of balance function. This scale evaluates balance function based on 14 tasks, with higher scores indicating a higher balance function. Other important functional assessments included the Stroke Impairment Assessment Set (SIAS)20) for patients with stroke and knee extension strength for patients with hip fracture. The SIAS comprehensively assesses functions commonly affected by stroke, which include motor function, sensory function, muscle tone, range of motion, non-affected side function, language and visuospatial perception, and pain. Knee extension strength was measured using a hand-held dynamometer (Tas F1; Anima, Tokyo, Japan) in the sitting position. The sensor was placed on the front of the distal lower leg and fixed with a belt and the therapist’s hand. To standardize the knee extension strength, the result was calculated as the average value for the left and right sides and was normalized relative to body weight and lower leg length. The Revised Hasegawa’s Dementia Scale (HDS-R) was used as an indicator of cognitive performance.21)
Data AnalysisTo determine whether bathing independence was correlated with balance function in patients with stroke and hip fracture, logistic regression was used, with bathing independence and the BBS being considered as the dependent and independent variables, respectively (crude model). In addition, logistic regression adjusting for age, gender, HDS-R, and SIAS in patients with stroke or knee extension strength in patients with hip fracture was also performed to adjust for confounders (adjusted model). Thereafter, we determined cutoff values using the receiver operating characteristic (ROC) curve. Accordingly, cutoff values were determined using the Youden Index when the area under the ROC curve (AUC) was greater than 0.7 (moderate accuracy).22) All statistical analyses were performed using SPSS Statistics for Windows Version 25.0 (IBM, Armonk, NY, USA) with the significance level set at less than 5%.
Patients with stroke had a mean age of 73.2±13.7 years, with men accounting for 57.7% of the cohort, whereas those with hip fracture had a mean age of 82.3±7.4 years, with men accounting for 18.6% of the cohort (Table 1). Of the 201 patients with stroke and the 59 patients with hip fracture, 72 (35.8%) and 32 (54.2%) were capable of independent bathing, respectively. The BBS scores were 39.0±17.5 and 40.5±14.5 for patients with stroke and those with hip fracture, respectively. The HDS-R scores were 22.5±7.3 and 21.5±7.6 for patients with stroke and those with hip fracture, respectively.
| Variable | Stroke (n=201) | Hip fracture (n=59) |
| Age, years | 73.2 (13.7) | 82.3 (7.4) |
| Male, % | 57.7 | 18.6 |
| Right-side affected, % | 50.7 | 50.8 |
| Post-onset period at admission, days | 28.3 (11.0) | 24.4 (7.8) |
| Length of hospital stay, days | 77.8 (34.7) | 56.6 (22.1) |
| Bathing item of Barthel Index at discharge | 0 (0–5) | 5 (0–5) |
| Bathing independence at discharge, % | 35.8 | 54.2 |
| Berg Balance Scale | 39.0 (17.5) | 40.5 (14.5) |
| HDS-R | 22.5 (7.3) | 21.5 (7.6) |
| SIAS | 59.3 (14.4) | |
| Knee extension strength, Nm/kg | 0.79 (0.31) |
Data given as mean (standard deviation), percentage, or median (interquartile range).
Logistic regression showed that in the crude model (univariate analysis), BBS was significantly associated with bathing independence in patients with stroke and hip fracture (P<0.01; Table 2, 3). In the adjusted model (multivariate analysis), the BBS remained significantly associated with bathing independence. ROC curve analysis showed that patients with hip fracture had an AUC of 0.88 [95% confidence interval (CI): 0.79–0.96, P<0.01] and those with stroke had an AUC of 0.90 (95% CI: 0.85–0.94, P<0.01) for independence of bathing based on the BBS. The calculated cutoff values for the BBS were 48 points for patients with stroke (sensitivity, 84.7%; specificity, 79.1%) and 43 points for patients with hip fracture (sensitivity, 81.3%; specificity, 77.8%).
| Crude model | Adjusted model | ||||
| Odds ratio (95% CI) |
P value | Odds ratio (95% CI) |
P value | ||
| Berg Balance Scale | 1.28 (1.18–1.38) | <0.01 | 1.21 (1.10–1.32) | <0.01 | |
| Age | 0.98 (0.95–1.03) | 0.44 | |||
| Gender (Women:1) | 0.72 (0.31–1.67) | 0.44 | |||
| HDS-R | 1.03 (0.95–1.11) | 0.53 | |||
| SIAS | 1.07 (1.00–1.14) | <0.05 | |||
| Crude model | Adjusted model | ||||
| Odds ratio (95% CI) |
P value | Odds ratio (95% CI) |
P value | ||
| Berg Balance Scale | 1.18 (1.08–1.29) | <0.01 | 1.17 (1.02–1.33) | <0.05 | |
| Age | 1.08 (0.96–1.22) | 0.20 | |||
| Gender (Women:1) | 5.48 (0.69–43.3) | 0.11 | |||
| HDS-R | 1.15 (0.99–1.33) | 0.07 | |||
| Knee extension strength | 1.43 (0.02–91.04) | 0.87 | |||
The current study investigated the relationship between bathing, the most difficult ADL to perform independently, and balance function for patients with stroke and hip fracture. The strengths of this study were as follows: (1) our inclusion of two major groups of patients requiring rehabilitation, namely those with stroke and hip fracture and (2) our examination of not only the relationship between bathing and balance function but also the level required for independence. The results of this study revealed cutoff values associated with bathing independence as measured by the BBS in patients with stroke and hip fracture.
An extensive survey of previous studies23,24) reported that the mean age at stroke onset was 74.3 years with men accounting for 46.1% of patients, whereas the mean age upon sustaining a hip fracture was 84.5 years with men accounting for 22.1% of patients. In our study population, patients with stroke had a mean age of 73.2 years (57.7% men), whereas those with hip fracture had a mean age of 82.3 years (18.6% men), a finding consistent with those presented in previous studies. Regarding the BBS score in previous studies that included patients similar to those included herein (i.e., those admitted to Japanese rehabilitation hospital wards), Tamura et al.25) found that patients with stroke had a median BBS score of 39.5, whereas Takeda et al.26) reported that patients with hip fracture had a mean BBS score of 39.7. These values are close to those obtained in the current study. Therefore, the participants of the current study do not appear to constitute a significantly biased sample.
The outcomes of logistic regression in this study revealed a relationship between bathing independence and balance function in patients with stroke and hip fracture. Age,27) gender,28) cognitive function,29) and the SIAS30) have been reported to be associated with ADL independence in patients with stroke. However, age,31) cognitive function,31) and knee extension muscle strength32) have also been reported to be associated with ADL independence in patients with hip fracture. In this study, bathing independence remained significantly associated with balance function after adjusting for these factors, suggesting that balance function is independently associated with bathing. The calculated odds ratios for BBS were 1.21 and 1.17 in patients with stroke and hip fracture, respectively, which were higher than those for age, gender, and other functions. Furthermore, considering that the BBS is a multistep scale ranging from 0 to 56 points, the odds ratio value of this study suggests that the influence of balance on bathing independence is large.
The BBS cutoff values associated with bathing independence calculated in this study were 48 points for patients with stroke and 43 points for patients with hip fracture. This could be a simple and useful indicator that could help rehabilitation professionals interpret the results of the BBS when conducting bathing interventions. In previous studies, several BBS cutoff values associated with ADL independence in patients with stroke have been reported: 39–43 points for toileting,33) 41–44 points for dressing,33,34) and 49–54 points for climbing stairs.33,35) Considering that bathing is one of the most difficult ADLs in patients with stroke36) and the values of other ADLs mentioned above, the calculated cutoff values for bathing in patients with stroke are considered reasonable. However, there was a 5-point difference in BBS cutoff values between patients with stroke and those with hip fracture. The minimal clinically important difference (MCID) for the BBS has been reported to be 4–5 points in patients with stroke,25) 3 points in those with multiple sclerosis,37) and 5 points in those with chronic obstructive pulmonary disease.38) Therefore, it is possible that the 5-point difference in the cutoff value between patients with stroke and those with hip fracture is beyond the margin of error. In fact, patients with hip fracture can compensate for balance function by grasping a support with both hands, which allows them to move and transfer more easily than patients with stroke hemiplegia. Therefore, the required balance function for bathing independence may have been lower for patients with hip fracture than for those with stroke. However, a score of 11.5 points for BBS was reported for MCID in patients with hip fracture,39) suggesting the need for further study.
One of the major limitations of this study is that it was conducted in a hospital setting. The hospital bathrooms are well equipped when compared with an average home; for example, handrails are installed, there are no steps at the toilet entrance, and shower chairs are available if necessary. Therefore, generalization of the results of this study would be restricted to hospitalized patients. Another limitation of the current study is that we also considered patients who were able to shower independently as being capable of independent bathing. This is because showering is easier than bathing in a bathtub. Therefore, bathing, which involves getting in and out of the bathtub, may require a balance function higher than the cutoff value established in the current study. Moreover, the sample size of patients with hip fracture was quite small for this study, suggesting the need for further studies with a larger sample size to confirm our findings.
The authors declare no conflict of interest.
This work was supported by the Japan Society for the Promotion of Science KAKENHI (grant no. 22K11422).
The authors declare that there are no conflict of interests.
