Longitudinal Analysis of Dysphagia and Factors Related to Postoperative Pneumonia in Patients Undergoing Esophagectomy for Esophageal Cancer.

Few studies have quantified longitudinal changes in swallowing in patients undergoing esophagectomy for esophageal cancer. This study longitudinally analyzed the changes in the Modified Barium Swallow Study Impairment Profile (MBSImP™) scores, swallowing kinematic measurements, and swallowing-related symptoms in patients undergoing esophagectomy. We also examined the association between identified swallowing impairment and aspiration pneumonia after surgery. We included consecutive patients who underwent esophagectomy and completed laryngoscopy and videofluoroscopy before, two weeks, and three months after surgery. We analyzed physiological impairments using the MBSImP. We also assessed the swallowing kinematics on a 5 mL thickened liquid bolus at three time points. Vocal fold mobility was assessed using a laryngoscope. Repeated measures were statistically examined for longitudinal changes in swallowing function. The association between the significant changes identified after esophagectomy and aspiration pneumonia was tested. Twenty-nine patients were included in this study. Preoperative swallowing function was intact in all participants. The timing of swallowing initiation and opening of the pharyngoesophageal segment remained unchanged after surgery. Tongue base retraction and pharyngeal constriction ratio worsened two weeks after surgery but returned to baseline levels three months after surgery. Three months after surgery, hyoid displacement and vocal fold immobility did not fully recover. Aspiration pneumonia occurred in nine patients after surgery and was associated with postoperative MBSImP pharyngeal residue scores. Decreased hyoid displacement and vocal fold immobility were observed postoperatively and persisted for a long time. The postoperative pharyngeal residue was associated with pneumonia and thus should be appropriately managed after surgery.

Treatments and outcomes of adult parapharyngeal and retropharyngeal abscess: 1882 cases from a Japanese nationwide database.

PURPOSE: Although parapharyngeal and retropharyngeal abscesses are potentially fatal deep neck abscesses, there is limited evidence for the treatment courses for adult patients with these abscesses. We aimed to describe the practice patterns and clinical outcomes of adult patients undergoing an emergency surgery for parapharyngeal or retropharyngeal abscesses using a nationwide database. MATERIALS AND METHODS: We identified patients aged ≥18 years who underwent emergency surgery for parapharyngeal (para group, n = 1148) or retropharyngeal (retro group, n = 734) abscesses from July 2010 to March 2020, using a nationwide inpatient database. We performed between-group comparisons of the baseline characteristics, treatment course, and outcomes. RESULTS: Compared with the retro group, the para group was more likely to be older (median, 66 vs. 60 years; P < 0.001) and have several comorbidities, such as diabetes (21 % vs 16 %; P = 0.010) and epiglottitis (33 % vs. 26 %; P = 0.002), except for peritonsillar abscess (14 % vs. 22 %; P < 0.001) and tonsillitis (2.1 % vs. 13 %; P < 0.001). Regarding intravenous drugs administered within 2 days of admission, approximately half of the patients received steroids, non-antipseudomonal penicillins, and lincomycins. The para group received more comprehensive treatments, such as tracheostomy, intensive care unit admissions, and swallowing rehabilitation, within total hospitalization than the retro group. Moreover, it demonstrated higher in-hospital mortality (2.7 % vs. 1.1 %; P = 0.017) and morbidity (16 % vs. 9.7 %; P < 0.001), and longer length of hospitalization than the retro group. CONCLUSION: The current nationwide study provided an overview of the characteristics, treatments, and outcomes for patients who underwent an emergency surgery for parapharyngeal or retropharyngeal abscess.

Predictive Factors for Oral Intake Recovery After Acute Stroke: Analysis of a Japanese Nationwide Inpatient Database.

OBJECTIVE: It remains unclear which factors contribute to dysphagia recovery after an acute stroke. This study aimed to identify factors associated with complete oral intake recovery in patients with post-stroke dysphagia. METHODS: Data were obtained from the Diagnosis Procedure Combination database, which is a nationwide database of administrative claims and discharge abstracts in Japan. We selected patients admitted within 3 days of stroke onset and conducted multivariable logistic regression analysis. Total oral intake within 30 days of admission was the primary outcome measure. RESULTS: A total of 151,302 patients were included, and total oral intake was observed in 48% of them within 30 days of admission. Total oral intake was significantly associated with age, sex, stroke subtype, consciousness disturbance, low body mass index, multiple comorbidities, and the modified Rankin Scale before stroke onset. In addition, males had worse outcomes than females (odds ratio, 0.75; 95% confidence interval, 0.73-0.77, p < 0.001), and intracerebral and subarachnoid hemorrhagic stroke subtypes were associated with non-recovery. CONCLUSION: This study identified several prognostic factors for total oral intake in patients with acute stroke. These results may be useful for predicting a patient's dysphagia prognosis at the time of admission and designing a nutritional management plan for patients with acute stroke.

Relationship Between Laryngeal Sensory Deficits, Aspiration, and Pneumonia in Patients with Dysphagia.

The laryngeal adductor reflex (LAR) is an airway protective reflex that manifests as a brief vocal fold closure in response to laryngeal stimulation. This study examined if the absence of the LAR in response to touch delivered by a laryngoscope is associated with penetration/aspiration or pneumonia in patients with dysphagia. Inpatients at a teaching hospital with clinical symptoms of dysphagia were recruited upon referral to the otolaryngology clinic for a swallowing evaluation. Otolaryngologists observed the status of secretions and touched each arytenoid with the tip of the laryngoscope. The patients were then asked to swallow 3-5 mL grape gelatin and 3-5 mL colored water. All procedures were video-recorded. Two independent raters noted absence/presence of the LAR and penetration/aspiration of pharyngeal secretions, gelatin, and water on the recorded videos. A diagnosis of pneumonia during the patient's entire hospital stay was determined by a review of the hospital's medical records. Statistical analyses were performed using Fisher's exact test. Sixty-one patients were included. Twenty-one patients (34.5%) did not exhibit the LAR. No association was found between the absent LAR and penetration or aspiration. There was, however, a significant association between an absence of the LAR and pneumonia development. Patients with an absent LAR had 6.8 times the odds of developing pneumonia as compared to those with a present LAR (OR 6.75; 95% CI 1.76-25.96; p < 0.01). Using the LAR as a marker of laryngeal sensory function appears to be valuable for identifying patients at high risk of pneumonia.

Electromyography of Swallowing with Fine Wire Intramuscular Electrodes in Healthy Human: Amplitude Difference of Selected Hyoid Muscles.

Few studies have examined the intensity of muscle activity during swallowing in healthy humans. We examined selected hyoid muscles using fine wire intramuscular electromyography (EMG) during swallowing of four food consistencies. Thirteen healthy adults were studied using videofluorography and EMG of the anterior belly of digastric (ABD), geniohyoid (GH), sternohyoid (SH), and masseter (MA; surface electrodes) while ingesting thin liquid (three trials) and solid food of three consistencies (banana, tofu, and cookie, three trials each). After rectification, integration, and normalization, peak EMG amplitudes for each muscle in each trial were measured. Hyoid displacements were measured in two dimensions. Data were analyzed using repeated measures ANOVA with Bonferroni correction. GH had the highest adjusted amplitude for both solids and liquid. For MA and ABD, amplitude was highest with triturated cookie. For ABD, amplitude was lowest with liquid. There were no significant food consistency effects for GH or SH. Hyoid displacements were greatest for cookie and the lowest for liquid. EMG amplitude varied with initial food consistency. The high peak EMG amplitude of GH is consistent with its essential role in opening the upper esophageal sphincter. High MA amplitude with hard solid foods is likely due to the higher tongue-palate pressure with triturated solids. The higher ABD amplitude with solid food is associated with greater hyoid displacement. These findings support the existence of a central pattern generator that modifies the level of muscle activity during pharyngeal swallowing in response to input from mechanoreceptors in the oral cavity.

Three-dimensional motion analysis of lumbopelvic rhythm during lateral trunk bending.

[Purpose] To examine the variations in the lumbopelvic rhythm and lumbar-hip ratio in the frontal plane. [Subjects and Methods] Markers were placed on the T10 and T12 spinous processes, bilateral paravertebral muscles at the T11 level, the pelvis, and the femur. Lumbar spine and hip angles were measured during lateral trunk bending using three-dimensional motion analysis. Data from the trunk lateral bending movement were categorized into descending (start of hip movement to when the hip angle reached its maximum value) and ascending (from the maximum hip angle to the end of movement) phases. The lumbar-hip ratio was calculated as the ratio of the lumbar spine angle to the hip angle. [Results] The lumbar-hip ratio decreased from 5.9 to 3.6 in the descending phase, indicating lumbar spinal movement was less than hip movement. In the ascending phase, the lumbar-hip ratio was reversed. The lumbopelvic rhythm was better expressed by a cubic or quadratic function rather than a linear function. These functions indicate that when the hip inclines by 1° that the lumbar spine bends laterally by 2.4°. [Conclusion] The lumbopelvic rhythm and lumbar-hip ratio indicate lumbar lateral bending instead of a limitation of hip inclination.

Neck range of motion measurements using a new three-dimensional motion analysis system: validity and repeatability.

PURPOSE: Neck movement is important for many activities of daily living (ADL). Neck disorders, such as cervical spondylosis and whiplash can limit neck movement and ADL. The cervical range of motion (CROM) device has been recently used to measure neck range of motion (ROM); however, this measurement includes trunk motion, and therefore does not represent a pure neck ROM measurement. The authors aimed to develop a new method to establish pure neck ROM measurements during flexion, extension, lateral bending, and rotation using a three-dimensional motion analysis system, VICON. METHODS: Twelve healthy participants were recruited and neck ROMs during flexion, extension, lateral bending, and rotation were measured using VICON and the CROM device. Test-retest repeatability was assessed using interclass correlation coefficients (ICCs), standard error of measurement (SEM), and minimal detectable change (MDC). Validity between two measurements was evaluated using a determination coefficient and Pearson's correlation coefficient. RESULTS: ICCs of neck ROM measured using VICON and the CROM device were all at substantial or almost perfect levels [VICON: ICC(1,2) = 0.786-0.962, the CROM device: ICC(1,2) = 0.736-0.950]. Both SEMs and MDCs were low in all measurement directions (VICON: SEM = 1.3°-4.5°, MDC = 3.6°-12.5°; the CROM device: SEM = 2.2°-3.9°, MDC = 6.1°-10.7°). Determination coefficients (R(2)s) and Pearson's correlation coefficients (rs) between the two measurement methods were high (R(2) = 0.607-0.745, r = 0.779-0.863). CONCLUSIONS: VICON is a useful system to measure neck ROMs and evaluate the efficacy of interventions, such as surgery or physiotherapeutic exercise.

Frequency of stage II oral transport cycles in healthy human.

Stage II transport (St2Tr) is propulsion of triturated food into the pharynx for storage before swallowing via tongue squeeze-back against the palate. To clarify the phenomenology of St2Tr, we examined the effects of food consistency and the number of chewing cycles on the number of St2Tr cycles in a chew-swallow sequence. We recorded chew-swallow sequences in lateral projection with videofluoroscopy of 13 healthy volunteers eating 6 g of hard (shortbread cookie), and soft foods (ripe banana and tofu) with barium. We counted the number of chewing and St2Tr cycles from food intake to terminal swallow. We used the Friedman test for bivariate analyses and negative binomial regression for multivariable analyses. On bivariate analysis, food consistency had a positive association with the number of chewing cycles (P = 0.013), but not with the number of St2Tr cycles (P = 0.27). Multivariable analysis, however, revealed a greater number of St2Tr cycles with hard than soft food (P ≤ 0.01) and a trend toward negative correlation between the numbers of St2Tr and chewing cycles (P = 0.083). The number of chewing cycles needed to clear the mouth differs among food consistencies as demonstrated previously. Greater numbers of both St2Tr and chewing cycles were elicited with the hard than with the soft foods. Given the trend toward negative correlation, the association between the number of St2Tr cycles and that of chewing cycles deserves further study.

Electromyography of swallowing with fine wire intramuscular electrodes in healthy human: activation sequence of selected hyoid muscles.

Few studies have reported the activation sequence of the swallowing muscles in healthy human participants. We examined temporal characteristics of selected hyoid muscles using fine wire intramuscular electromyography (EMG). Thirteen healthy adults were studied using EMG of the anterior belly of digastric (ABD), geniohyoid (GH), sternohyoid (SH), and masseter (MA, with surface electrodes) while ingesting thin liquid, banana, tofu, and cookie (3 trials each). Onset timing was measured from rectified and integrated EMG. Data were analyzed using repeated-measures ANOVA with Bonferroni correction. When drinking thin liquid, MA, GH, and ABD were activated almost simultaneously, but SH was activated later (using GH onset as 0 s, MA -0.07 (-0.20 to 0.17) second [median (interquartile range)]; ABD 0.00 (-0.10 to 0.07) second; SH 0.17 (0.02 to 0.37) second; P < 0.01). With solid foods, MA contraction preceded GH and ABD; SH was last and delayed relative to liquid swallows (GH 0 s; MA -0.17 (-0.27 to 0.07) second; ABD 0.00 (-0.03 to 0.03) second; SH 0.37 (0.23 to 0.50) second; P < 0.01). The role of the MA differs between solids and liquids so the variation in its timing is expected. The synchronous contraction of GH and ABD was consistent with their role in hyolaryngeal elevation. The SH contracted later with solids, perhaps because if the longer duration of the swallow. The consistent pattern among foods supports the concept of a central pattern generator for pharyngeal swallowing.

Services in public long-term care insurance in Japan.

In Japan, a public long-term care insurance system was launched in 2000. Residents can receive long-term care according to their care needs, as determined by a nationally standardized certification system. The present report describes the details of the long-term care services covered by public insurance. The Long-Term Care Insurance Act categorizes services into three major types: in-home, nursing-home, and community-based long-term care services. In-home care services include visiting, commuting, short-stay, and other services. Welfare, health, and medical facilities provide nursing-home care services for the elderly. Community-based care services were categorized into visiting, commuting, nursing-home, and composite services.

Implicit learning provides advantage over explicit learning for gait-cognitive dual-task interference.

Dual-task performance holds significant relevance in real-world scenarios. Implicit learning is a possible approach for improving dual-task performance. Analogy learning, utilizing a single metaphor to convey essential information about motor skills, has emerged as a practical method for fostering implicit learning. However, evidence supporting the effect of implicit learning on gait-cognitive dual-task performance is insufficient. This exploratory study aimed to examine the effects of implicit and explicit learning on dual-task performance in both gait and cognitive tasks. Tandem gait was employed on a treadmill to assess motor function, whereas serial seven subtraction tasks were used to gauge cognitive performance. Thirty healthy community-dwelling older individuals were randomly assigned to implicit or explicit learning groups. Each group learned the tandem gait task according to their individual learning styles. The implicit learning group showed a significant improvement in gait performance under the dual-task condition compared with the explicit learning group. Furthermore, the implicit learning group exhibited improved dual-task interference for both tasks. Our findings suggest that implicit learning may offer greater advantages than explicit learning in acquiring autonomous motor skills. Future research is needed to uncover the mechanisms underlying implicit learning and to harness its potential for gait-cognitive dual-task performance in clinical settings.

Association between Care-need Level after Discharge and Long-term Outcomes in 7491 Patients Requiring Rehabilitation for Stroke.

Introduction: Stroke is a major cause of disability and mortality worldwide and requires long-term care, including rehabilitation. This study aims to elucidate the association between care-need levels after discharge and long-term outcomes in patients with stroke. Methods: We used a Japanese administrative database that covers both medical and long-term care insurance systems to retrospectively identify 7491 patients who underwent acute-phase in-hospital rehabilitation for stroke between June 2014 and February 2019. We investigated the association between nationally standardized care-need levels (support levels 1-2 and care-need levels 1-3) 6 months after discharge and long-term outcomes. Using the Fine-Gray model, we conducted multivariable survival analysis with adjustment for patient backgrounds and treatment courses to estimate hazard ratios (HR) for mortality and the incidence of being bedridden. Results: The median age was 82 (interquartile range [IQR], 76-87) years, 5418 patients (72%) had cerebral infarction, and 4009 patients (54%) had partial dependence after discharge. During a median follow-up of 580 (IQR, 189-925) days, 1668 patients (22%) became bedridden, and 2174 patients (29%) died. Compared with patients with support level 1, those with higher care-need levels showed significantly higher proportions of being bedridden-the subdistribution HR [95% confidence interval] were 1.52 [1.10-2.12], 2.85 [2.09-3.88], and 3.79 [2.79-5.15] in those with care-need levels 1, 2, and 3, respectively. Higher care-need levels were also significantly associated with higher mortality. Conclusions: This large-scale observational study demonstrated that a higher level of care-need after discharge was significantly associated with poorer functional outcomes and higher mortality.

Fluoroscopic evaluation of tongue and jaw movements during mastication in healthy humans.

When chewing solid food, part of the bolus is propelled into the oropharynx before swallowing; this is named stage II transport (St2Tr). However, the tongue movement patterns that comprise St2Tr remain unclear. We investigated coronal jaw and tongue movements using videofluorography. Fourteen healthy young adults ate 6 g each of banana, cookie, and meat (four trials per foodstuff). Small lead markers were glued to the teeth and tongue surface to track movements by videofluorography in the anteroposterior projection. Recordings were divided into jaw motion cycles of four types: stage I transport (St1Tr), chewing, St2Tr, and swallowing. The range of horizontal tongue motion was significantly larger during St1Tr and chewing than during St2Tr and swallowing, whereas vertical tongue movements were significantly larger during chewing and St2Tr than during swallowing. Tongue movements varied significantly with food consistency. We conclude that the small horizontal tongue marker movements during St2Tr and swallowing were consistent with a "squeeze-back" mechanism of bolus propulsion. The vertical dimension was large in chewing and St2Tr, perhaps because of food particle reduction and transport in chewing and St2Tr.

Development, reliability, and validation of an infant mammalian penetration-aspiration scale.

A penetration-aspiration scale exists for assessing airway protection in adult videofluoroscopy and fiberoptic endoscopic swallowing studies; however, no such scale exists for animal models. The aim of this study was threefold: (1) develop a penetration-aspiration scale (PAS) for infant mammals, (2) test the scale's intra- and interrater reliabilities, and (3) validate the use of the scale for distinguishing between abnormal and normal animals. After discussion and reviewing many videos, the result was a 7-point infant mammal PAS. Reliability was tested by having five judges score 90 swallows recorded with videofluoroscopy across two time points. In these videos, the frame rate was either 30 or 60 frames per second and the animals were either normal, had a unilateral superior laryngeal nerve (SLN) lesion, or had hard palate local anesthesia. The scale was validated by having one judge score videos of both normal and SLN lesioned pigs and testing the difference using a t test. Raters had a high intrarater reliability [average κ = 0.82, intraclass correlation coefficient (ICC) = 0.92] and high interrater reliability (average κ = 0.68, ICC = 0.66). There was a significant difference in reliability for videos captured at 30 and 60 frames per second for scores of 3 and 7 (P < 0.001). The scale was also validated for distinguishing between normal and abnormal pigs (P < 0.001). Given the increasing number of animal studies using videofluoroscopy to study dysphagia, this scale provides a valid and reliable measure of airway protection during swallowing in infant pigs that will give these animal models increased translational significance.

Development of new measurement system of thoracic excursion with biofeedback: reliability and validity.

BACKGROUND: Respiratory rehabilitation reduces breathlessness from patient with respiratory dysfunction. Chest expansion score, which represents the circumference magnitude of the thoracic cage, is used for a target when treating patients with respiratory disease. However, it is often difficult for patients to understand the changes in the respiratory status and be motivated for therapy continuously. We developed a new measurement system with biofeedback named BREATH which shows chest expansion scores in real time. The purpose of this study was to determine the reliability and validity of the novel system in advance of clinical application. METHODS: Three evaluators measured chest expansion in 33 healthy individuals using tape measure, which is used for the measurement traditionally, and BREATH. The wire for BREATH system was threaded over the thoracic continuously and the data was recorded automatically; whereas the tape was winded and measured each maximal expiration and inspiration timing by evaluator. All participants were performed both measurement simultaneously for three times during deep breath. In this study, we studied chest expansion score without using biofeedback data of BREATH to check the validity of the result. To confirm intra- and inter-evaluator reliability, we computed intra-class correlations (ICCs). We used Pearson's correlation coefficient to evaluate the validity of measurement result by BREATH with reference to the tape measure results. RESULTS: The average (standard deviation) chest expansion scores for all, men and women by the tape measure were 5.53 (1.88), 6.40 (1.69) and 5.22 (1.39) cm, respectively, and those by BREATH were 3.89 (2.04), 4.36 (1.83) and 2.89 (1.66) cm, respectively. ICC within and among the three evaluators for BREATH and the tape measure were 0.90-0.94 and 0.85-0.94 and 0.85 and 0.82, respectively. The correlation coefficient between the two methods was 0.76-0.87. CONCLUSION: The novel measurement system, BREATH, has high intra- and inter-evaluator reliabilities and validity; therefore it can lead us more effective respiratory exercise. Using its biofeedback data, this system may help patients with respiratory disease to do exercises more efficiently and clinicians to assess the respiratory exercise more accurately.

Esophageal Speech for a Patient with Amyotrophic Lateral Sclerosis Who Underwent a Central-part Laryngectomy to Prevent Aspiration: A Case Report.

Background: To prevent aspiration, patients with irreversible dysphagia may undergo surgeries that separate the esophagus and trachea. Such interventions result in loss of vocal function and require alternative communication methods. We report a patient with amyotrophic lateral sclerosis (ALS) who used esophageal speech after receiving a central-part laryngectomy (CPL) to prevent aspiration. Case: A 64-year-old woman with ALS was admitted to our hospital. The patient maintained good cognitive and oral function and presented with mild dysarthria and dysphagia. Faced with rapidly worsening respiratory distress, saliva aspiration, and excessive sputum, she underwent a tracheostomy on the premise of invasive ventilation. Subsequently, the patient began using a voice-generating application for communication. Given the patient's sincere hope to prevent aspiration and aspiration pneumonia, achieve safe oral intake, and decrease caregiver burden for frequent suctioning, the patient underwent a CPL. Following surgery, belching was observed during meals, and the patient could phonate when she belched. This finding led to four speech therapy sessions to practice esophageal speech, allowing the patient to use the pseudo-speech technique for short conversations. Removal of the entire cricoid cartilage in the CPL decreases the upper esophageal sphincter (UES) pressure, thereby allowing air to easily pass through the UES. Therefore, the patient could use the air as a sound source for esophageal speech without extensive training. Discussion: Esophageal speech may be an alternative to oral communication in patients undergoing CPL. Further research is warranted to generalize these findings to patients undergoing CPL.

Food transit duration is associated with the number of stage II transport cycles when eating solid food.

OBJECTIVE: When eating solids, stage II transport (St2Tr) propels triturated food into the pharynx for bolus formation and storage before swallowing. Although the existence of St2Tr is acknowledged, the reason for its existence remains unclear. Understanding it may facilitate development of food appropriate for individuals with dysphagia. The purpose of this study was to explore how measures of duration of eating and swallowing affect the number of St2Tr cycles. DESIGN: Videofluorography was performed on 13 healthy subjects eating 6-g squares of banana, tofu, and cookies. Measurements included the number of St2Tr cycles, duration of processing (from food entering the mouth to onset of swallowing), pre-upper esophageal sphincter (UES) transit duration (from onset of swallowing to onset of UES transit), UES transit duration (leading edge to trailing edge passing the UES), and total sequence duration (from onset of swallowing to terminal swallow). Principal component (PC) analysis was used to identify factors affecting the number of St2Tr cycles. Analysis of covariance was performed using the 1st PC as an independent variable for predicting the number of St2Tr cycles. RESULTS: All four duration measures were significantly positively correlated with the number of St2Tr cycles. Analysis revealed two orthogonal PCs with variable loading. The 1st PC was a function of the timing variables. The 2nd PC was a function of the number of swallows. CONCLUSIONS: The number of St2Tr cycles was associated with measures of food transit duration and was greater with harder foods before processing and more viscous foods just before swallowing.

Mortality-Reducing Effect of Rehabilitation for COPD: Observational Propensity-Matched Cohort Study Using a Nationwide Database.

BACKGROUND: In the course of therapy of patients with COPD, non-pharmacologic treatment, such as rehabilitation, plays an important role. Although some studies have provided concrete evidence of the effectiveness of rehabilitation in improving functional outcomes in subjects with COPD, evidence of its mortality-reducing effect has been insufficient. In the present study, we examined whether rehabilitation had positive effects on in-hospital mortality of subjects with COPD. METHODS: We used the Japanese Diagnosis Procedure Combination nationwide administrative claims database. This was a retrospective cohort study, and there were 18,037 eligible subjects with COPD from 1,055 hospitals. The main outcome was in-hospital mortality rates. A one-to-one propensity score matching method was used to compare hospital mortality rates after admission between rehabilitation and non-rehabilitation groups. RESULTS: A total of 3,356 pairs of subjects were selected from the rehabilitation and non-rehabilitation groups (n = 6,712). Subjects in the rehabilitation program showed a reduction in the odds of mortality (odds ratio = 0.80, 95% CI 0.65-1.00, P = .045). In the subgroup analyses, the rehabilitation group had a lower in-hospital mortality in the pre-obese subgroup (body mass index 25.0-29.9) than the non-rehabilitation group (P = .02). Although not significant, the rehabilitation group showed a relatively low in-hospital mortality in the Hugh-Jones dyspnea scale class 5 subgroup (P = .066). CONCLUSIONS: This large nationwide cohort study showed that rehabilitation indeed contributed to a reduction of in-hospital mortality. These findings underscore the importance of adopting rehabilitation as part of the treatment of COPD.