Linguistic and Psychometric Validation of the Cognition Bolt-On Version of the Japanese EQ-5D-5L for the Elderly.

BACKGROUND: The need for a cognition bolt-on version of the EQ-5D, which would capture cognitive impairment by adding a dimension to the generic instrument assessing health status, has been increasing in Japan. OBJECTIVE: To develop a cognition bolt-on version of the 5-level EQ-5D (EQ-5D-5L+C), we linguistically validated a cognition dimension and psychometrically validated the EQ-5D-5L+C. METHODS: Following linguistic validation of the cognition dimension, psychometric validation of the EQ-5D-5L+C proxy version utilized anonymized data collected from nursing home residents between October 2021 to April 2022. The validity, reliability, and sensitivity to change were evaluated. RESULTS: Data from 254 participants, including the finalized Japanese EQ-5D-5L+C proxy version, were analyzed for the psychometric validation. Mean (±standard deviation) age and Mini-Mental State Examination (MMSE) scores were 87.14±7.29 years and 15.76±8.46, respectively. The correlation was strongest between the cognition dimension and MMSE scores (rs = -0.640). Test-retest reliability was good in the cognition dimension in both baseline and two-time points (3 months: k = 0.644; 6 months: k = 0.656). Although a correlation between changes in the cognition dimension and those in the MMSE score from baseline was weak (3 months: rs = -0.191; 6 months: rs = -0.267), a correlation with changes in the MMSE score was higher when the cognition dimension was added compared to the EQ-5D alone (3 months: rs = -0.142 versus rs = -0.074). CONCLUSION: The Japanese EQ-5D-5L+C proxy version developed is a valid tool that captures health status including cognitive function, with a consideration for an over-time assessment. The benefits in adding the cognition dimension to the EQ-5D-5L to assess health state were suggested.

Assessment of risk factors for non-specific chronic disabling low back pain in Japanese workers-findings from the CUPID (Cultural and Psychosocial Influences on Disability) study.

The majority of patients with non-specific low back pain (LBP) suffer from chronic pain. Psychosocial factors play an important role in the chronicity of LBP. To explore the risk factors for chronic disabling LBP in detail, we assessed its various risk factors in Japanese workers, using data from the Cultural and Psychosocial Influences on Disability (CUPID) study. Data were drawn from a 1 yr follow-up of 20‒59 yr-old workers who participated in the CUPID study. A self-administered questionnaire assessed various factors, including individual characteristics, ergonomic work demands, and work-related or other psychosocial factors. Logistic regression analyses were performed to assess the associations between these factors and chronic disabling LBP. Of 198 participants, 35 (17.7%) had chronic disabling LBP during the 1 yr follow-up. Multivariate logistic regression analysis revealed that the interaction effect of the two factors, expectation of LBP problems and excessive working hours (≥ 60 h per week), was associated with chronic disabling LBP. Chronic disabling LBP was present in 42.5% of participants with both of these two risk factors, whereas it was present in 11.8% of participants without these risk factors. In conclusion, among various factors, the combination of two psychosocial factors was particularly associated with chronic disabling LBP.

Development of the Japanese Core Outcome Measures Index (COMI): cross-cultural adaptation and psychometric validation.

BACKGROUND: The patient-rated Core Outcome Measures Index (COMI) assesses the multidimensional impact of back problems on the sufferer. The brevity and comprehensibility of the tool make it practical for use in clinical and research settings. Although the COMI has been cross-culturally adapted in various languages worldwide, there is currently no Japanese version. The aim of this study was to develop a Japanese version of the COMI by: (1) performing a cross-cultural adaptation of the English version and (2) evaluating the psychometric properties of the Japanese version of the COMI in Japanese volunteers with chronic back problems. METHODS: The English version of the COMI was cross-culturally adapted for the Japanese language using established guidelines. The pre-final version was pilot-tested in five Japanese-speaking patients with low back pain (LBP) and a history of spine surgery. The psychometric properties of the Japanese COMI were tested in a group of 1052 individuals with chronic LBP (LBP ≥3 months), aged 20-69 years, who were recruited through a web-based survey. The psychometric properties that were evaluated included convergent and known-group validity, using the following reference questionnaires: EuroQol 5 Dimension, Roland Morris Disability Questionnaire, Short Form 8™ Health Survey, and the Keele STarT Back Screening Tool. RESULTS: The pre-final version of the cross-culturally adapted Japanese COMI was completed without any major problems of understanding or acceptability. For the evaluation of its psychometric properties, tests for convergent validity showed moderate correlations between COMI items and the respective reference questionnaires for symptom-specific well-being [- 0.33--0.48] and disability domains [0.48] and strong correlations (> 0.5) for the other domains and the COMI summary score. The analysis of known-group validity showed a linear trend for the COMI score in relation to prognostic risk (P < 0.001). CONCLUSIONS: The Japanese COMI retained conceptual equivalence to the original using comprehensible and acceptable Japanese expressions. We developed a Japanese version of the COMI that displayed qualities that support its convergent and known-group validity. The availability of a Japanese version of the COMI should allow for improved documentation of the care provided to patients with back problems.

Assessment of potential risk factors for new onset disabling low back pain in Japanese workers: findings from the CUPID (cultural and psychosocial influences on disability) study.

BACKGROUND: Most studies of risk factors for new low back pain (LBP) have been conducted in Western populations, but because of cultural and environmental differences, the impact of causal factors may not be the same in other countries. We used longitudinal data from the Cultural and Psychosocial Influences on Disability (CUPID) study to assess risk factors for new onset of disabling LBP among Japanese workers. METHODS: Data came from a 1-year prospective follow-up of nurses, office workers, sales/marketing personnel, and transportation workers, initially aged 20-59 years, who were employed in or near Tokyo. A baseline questionnaire included items on past history of LBP, personal characteristics, ergonomic work demands, and work-related psychosocial factors. Further information about LBP was collected at follow-up. Analysis was restricted to participants who had been free from LBP during the 12 months before baseline. Logistic regression was used to assess baseline risk factors for new onset of disabling LBP (i.e. LBP that had interfered with work) during the 12 months of follow-up. RESULTS: Among 955 participants free from LBP during the 12 months before baseline, 58 (6.1%) reported a new episode of disabling LBP during the 12-month follow-up period. After mutual adjustment in a multivariate logistic regression analysis, which included the four factors that showed associations individually (p < 0.1) in analyses adjusted only for gender and age, the highest odds ratio (OR) was for past history of LBP (2.8, 95% [confidence interval {CI}]: 1.6-4.9), followed by working ≥60 h per week (1.8, 95% CI: 1.0-3.5) and lifting weights ≥25 kg by hand (1.6, 95% CI: 0.9-3.0). When past history of LBP was excluded from the model, ORs for the remaining risk factors were virtually unchanged. CONCLUSIONS: Our findings suggest that among Japanese workers, as elsewhere, past history of LBP is a major risk factor for the development of new episodes of disabling back pain. They give limited support to the association with occupational lifting that has been observed in earlier research, both in Japan and in Western countries. In addition, they suggest a possible role of long working hours, which merits further investigation.

Development of a Japanese version of the Somatic Symptom Scale-8: Psychometric validity and internal consistency.

OBJECTIVE: We aimed to psychometrically validate the Japanese version of the Somatic Symptom Scale-8 (SSS-8) in Japanese individuals. METHOD: Data were collected from Japanese individuals aged 20-64years, who were recruited online, in February 2015. The scale reliability and validity were analyzed. RESULTS: Data from 52,353 individuals were analyzed. Cronbach's alpha for the assessment of internal consistency reliability was 0.86 for the total score. The concurrent validity results showed strong correlations with three domains of the Profile of Mood States-Brief form (ρ=0.51-0.61) and the EuroQol 5 Dimension (ρ=-0.54). The known-group validity results indicated a linear trend in the severity of depression stratified using the Patient Health Questionnaire-2 (Jonckheere-Terpstra test, p<0.001). Regarding convergent and discriminant validities, all items correlated most strongly with their own domains (coefficients≥0.5), except for one item (headaches). Scores on perceived stress, pain, and general health differed across five SSS-8 severity groups (Steel-Dwass test, p<0.001), expect for one group pair in health. CONCLUSION: The Japanese version of the SSS-8 was valid with good internal consistency. This questionnaire could help detect somatic symptom burdens of chronic and severe musculoskeletal pain for primary prevention.

Psychometric assessment of the Japanese version of the Revised Fibromyalgia Impact Questionnaire: reliability and validity.

AIM: To assess the psychometric properties of the Japanese version of the Revised Fibromyalgia Impact Questionnaire (JFIQR) in fibromyalgia (FM) patients. METHOD: The reliability and validity of the JFIQR were assessed using online data collected from Japanese FM patients. Reliability was evaluated based on test-retest reliability results and internal consistency; validity was evaluated on the basis of concurrent and known-group validity. RESULTS: A total of 105 patients completed the online questionnaire. Intra-class correlation coefficients for test-retest were 0.91 for the JFIQR total score with a range of 0.84-0.90 in three domains: function, overall impact and symptoms. Internal consistency results indicated a Cronbach's alpha of 0.90 for the total score with a range of 0.83 and 0.85 for the domains. Concurrent validity results showed that the total score was correlated to all external criteria (Japanese version of the Fibromyalgia Impact Questionnaire, Fibromyalgia Activity Scale-31, Medical Outcomes Study 36-item Short-Form health survey) from a moderate to strong degree with most indicating a strong correlation. Results of known-group validity showed that the JFIQR total score is capable of discriminating between FM and the other groups, such as rheumatic arthritis and no chronic pain (P < 0.0001 for all pairwise comparisons). CONCLUSION: The current psychometric assessment of the JFIQR demonstrated that it is a reliable and valid questionnaire in Japanese patients with FM. Usefulness of the JFIQR in clinical studies and medical practice for Japanese-speaking populations is expected.

Development of the Japanese Version of the Leeds Assessment of the Neuropathic Symptoms and Signs Pain Scale: Diagnostic Utility in a Clinical Setting.

OBJECTIVE: We aimed to assess the diagnostic utility of the linguistically validated Japanese version of the Leeds Assessment of Neuropathic Symptoms and Signs Pain Scale (LANSS-J) as a screening tool for neuropathic pain in the clinical setting. METHODS: Patients with neuropathic pain or nociceptive pain who were 20 to 85 years of age were included. Sensitivity and specificity using the original cutoff value of 12 were assessed to evaluate the diagnostic utility of the LANSS-J. Sensitivity and specificity with possible cutoff values were calculated, along with area under the receiver operating characteristic curve. We then evaluated agreement regarding assessment of the LANSS-J by two investigators. We used the intraclass correlation coefficient (ICC) for the total score and Cohen's kappa coefficient for each item. RESULTS: Data for patients with neuropathic pain (n = 30) and those with nociceptive pain (n = 29) were analyzed. With a cutoff of 12, the sensitivity was 63.3% (19/30) and the specificity 93.1% (27/29). Sensitivity improved substantially with a cutoff of ≤ 11 (≥ 83.3%, 25/30). High specificity (93.1%, 27/29) was sustained with a cutoff of 9 to 12. The ICC for the total score was 0.85, indicating sufficient agreement. Kappa coefficients ranged from 0.68 to 0.84. CONCLUSIONS: The LANSS-J is a valid screening tool for detecting neuropathic pain. Our results suggest that employing the original cutoff value provides high specificity, although a lower cutoff value of 10 or 11 (with its high specificity maintained) may be more beneficial when pain attributed to neuropathic mechanisms is suspected in Japanese patients.

Assessment of psychosocial risk factors for the development of non-specific chronic disabling low back pain in Japanese workers-findings from the Japan Epidemiological Research of Occupation-related Back Pain (JOB) study.

To investigate the associations between psychosocial factors and the development of chronic disabling low back pain (LBP) in Japanese workers. A 1 yr prospective cohort of the Japan Epidemiological Research of Occupation-related Back Pain (JOB) study was used. The participants were office workers, nurses, sales/marketing personnel, and manufacturing engineers. Self-administered questionnaires were distributed twice: at baseline and 1 yr after baseline. The outcome of interest was the development of chronic disabling LBP during the 1 yr follow-up period. Incidence was calculated for the participants who experienced disabling LBP during the month prior to baseline. Logistic regression was used to assess risk factors for chronic disabling LBP. Of 5,310 participants responding at baseline (response rate: 86.5%), 3,811 completed the questionnaire at follow-up. Among 171 eligible participants who experienced disabling back pain during the month prior to baseline, 29 (17.0%) developed chronic disabling LBP during the follow-up period. Multivariate logistic regression analysis implied reward to work (not feeling rewarded, OR: 3.62, 95%CI: 1.17-11.19), anxiety (anxious, OR: 2.89, 95%CI: 0.97-8.57), and daily-life satisfaction (not satisfied, ORs: 4.14, 95%CI: 1.18-14.58) were significant. Psychosocial factors are key to the development of chronic disabling LBP in Japanese workers. Psychosocial interventions may reduce the impact of LBP in the workplace.

Identification of risk factors for new-onset sciatica in Japanese workers: findings from the Japan epidemiological research of Occupation-related Back pain study.

STUDY DESIGN: Two-year, prospective cohort data collected for the Japan epidemiological research of Occupation-related Back pain study were used for the analysis. OBJECTIVE: To identify potential risk factors for the development of new-onset sciatica in initially symptom-free Japanese workers with no history of sciatica. SUMMARY OF BACKGROUND DATA: Although the associations between individual and occupational factors and cases of new-onset sciatica are established, the effect of psychosocial factors on the development of sciatica has still not been adequately clarified. METHODS: In total, 5310 participants responded to a self-administered baseline questionnaire (response rate: 86.5%). Furthermore, 3194 (60.2%) completed both 1- and 2-year follow-up questionnaires. The baseline questionnaire assessed individual characteristics, ergonomic work demands, and work-related psychosocial factors. The outcome of interest was new-onset sciatica with or without low back pain during the 2-year follow-up period. Incidence was calculated for participants who reported no low back pain in the preceding year and no history of lumbar radicular pain (sciatica) at baseline. Logistical regression assessed risk factors associated with new-onset sciatica. RESULTS: Of 765 eligible participants, 141 (18.4%) reported a new episode of sciatica during the 2-year follow-up. In crude analysis, significant associations were found between new-onset sciatica and age and obesity. In adjusted analysis, significant associations were found for obesity and mental workload in a qualitative aspect after controlling for age and sex. Consequently, in multivariate analysis with all the potential risk factors, age and obesity remained statistically significant (odds ratios: 1.59, 95% confidence interval: 1.01-2.52; odds ratios: 1.77, 95% confidence interval: 1.17-2.68, respectively). CONCLUSION: In previously asymptomatic Japanese workers, the risk of developing new-onset sciatica is mediated by individual factors. Our findings suggest that the management of obesity may prevent new-onset sciatica. LEVEL OF EVIDENCE: 3.