Predictors of functional deterioration in Chinese patients with psoriatic arthritis: a longitudinal study.

BACKGROUND: Psoriatic arthritis (PsA) disease activities at baseline may determine physical function over time. There is no longitudinal data on course of physical function in PsA patients from Asia. We aim to describe variables associated with a deterioration of physical function in PsA in Chinese over a 6-year period. METHODS: 125 consecutive patients with PsA fulfilled the CASPAR criteria from a rheumatology outpatient center were recruited to give sociodemographic and clinical data in 2006 to 2008. Follow up interviews were conducted in 2012 to 2013 to assess physical function using Health Assessment Questionnaire (HAQ). Regression models were constructed to determine baseline variables that predict physical function on follow up. RESULTS: A total of 97 patients completed the follow up survey, with mean follow up time of 6.2 (±0.7) years, response rate 77.6%. PsA patients had poor physical function and health related quality of life (HRQoL) compared to normal population. There were 33% who improved in disability status and 41.2% had persistent minimal disability by HAQ categories (HAQ 0-0.49) over time. There were 14.4% of the patients who had persistent moderate disability (HAQ 0.5-1.50) and 10.3% had deterioration in disability status. There were 17.5% of patients who had deterioration in physical function as defined by an increment of HAQ score of more than 0.2 at follow up survey. Age, physical function at baseline and the number of damaged joint were significantly related HAQ at follow up. CONCLUSION: Chinese patients with PsA had had poor physical function and quality of life. One fifth of patient experienced deterioration of physical function over time. Joint damage and baseline physical function were important factors associated with poor physical function in PsA over time.

Validation of a wearable forehead sleep recorder against polysomnography in sleep staging and desaturation events in a clinical sample.

STUDY OBJECTIVES: Wearable sleep recording devices may be a helpful alternative method for polysomnography (PSG) due to their higher accessibility and comfort as well as lower cost, but their validities need to be examined. The aim of this study was to evaluate the accuracy of a novel single-channel, electroencephalography-based wearable forehead sleep recorder (UMindSleep) to assess sleep staging and oxygen desaturation. METHODS: Two hundred and three Chinese adults recruited from a sleep medicine center underwent an overnight study wearing UMindSleep and PSG simultaneously. Sleep parameters including sleep staging and oxygen desaturation index were compared between UMindSleep and PSG. RESULTS: A total of 195,349 valid epochs from 197 participants (171 with obstructive sleep apnea, 86.8%) were included in analyses of sleep staging. Sensitivities of UMindSleep compared to PSG were 79.7% for wake, 85.8% for light sleep, 79.4% for deep sleep, and 82.7% for rapid eye movement sleep. Specificities were 95.3% for wake, 83.4% for light sleep, 97.0% for deep sleep, and 96.8% for rapid eye movement sleep. Furthermore, the kappa agreements of 0.69-0.79 were indicative of a substantial agreement for sleep staging between UMindSleep and PSG. Sensitivity and specificity regarding oxygen desaturation index were 93.4% and 88.9%, yielding a kappa coefficient of 0.82. CONCLUSIONS: Our findings suggest that UMindSleep may serve as a feasible, accurate, and dependable device for screening of sleep disorders (eg, obstructive sleep apnea) and assessing sleep structure. CITATION: Chen X, Jin X, Zhang J, Ho KW, Wei Y, Cheng H. Validation of a wearable forehead sleep recorder against polysomnography in sleep staging and desaturation events in a clinical sample. J Clin Sleep Med. 2023;19(4):711-718.

Testing scaling assumptions, reliability and validity of medical outcomes study short-form 36 health survey in psoriatic arthritis.

OBJECTIVES: The Medical Outcome Survey short-form 36 (SF-36) is widely used in studies of PsA. We test the fundamental scaling assumptions for the validity of SF-36 eight scales and two summary scores in PsA. METHODS: We tested the five scaling criteria according to the International Quality of Life Assessment project and the validity of the physical component summary (PCS) and mental component summary (MCS) scores. The construct validity for SF-36 in PsA was evaluated. RESULTS: A total of 168 PsA subjects according to CASPAR criteria (46.4% females) with SF-36 data were analysed. The mean (S.D.) age and duration of illness were 47.7 (11.9) and 8.4 (7.3) years. PsA subjects had poorer quality of life as compared with normal population. The norm-based mean (S.D.) PCS and MCS were 31.6 (14.2) and 45.2 (12.7), respectively. The Pearson's correlations between an item and its hypothesized scale were all >0.4, indicating item internal consistency. All item-own scale correlations exceed item-other scale correlations, except minor scaling failure in general health. The Cronbach's alpha-coefficients of internal reliability (Cronbach's alpha) were all above the standard value of 0.7, indicating a unique concept in each scale. Principal component analysis explained 69.4 and 73.7-99.9% of the total variance and total reliable variance in all SF-36 scales. The two-factor model is supported. CONCLUSIONS: PsA had high impact on quality of life. All eight scales and two summary scores of SF-36 satisfied criteria for scaling assumption. SF-36 is a valid measurement for quality of life in PsA. The reporting of PCS and MCS in PsA is supported.

Construct validity of the modified numeric rating scale of patient global assessment in psoriatic arthritis.

OBJECTIVE: The construct validity of the patient global health assessment (PGA) in psoriatic arthritis (PsA) has not been analyzed, despite its common use. We evaluated the construct validity of a numeric rating scale (NRS) of the PGA in PsA. METHODS: Patients with PsA who fulfilled the ClASsification for Psoriatic ARthritis (CASPAR) criteria were recruited at a tertiary referral center. Demographic data were collected and PGA data were determined from administration of an 11-point NRS (0 to 10 points representing best to worst status). Convergent and discriminant validity were evaluated by correlation between PGA and clinical variables. Patients were grouped as having severe disease based on Disease Activity Score 28-joint count (DAS28) > 5.1, Health Assessment Questionnaire (HAQ) > 1.0, walking with aids, and social welfare-dependent. Patients were grouped as being in remission by DAS28 < 2.6 and the Minimal Disease Activity Criteria. Known-group validity of PGA was evaluated. RESULTS: A total of 125 patients (52% men) were studied. Convergent validity revealed strong correlations of PGA with pain score, HAQ, and DAS28; and weak correlations with skin severity score, physician's global assessment and morning stiffness. In multivariate analysis, PGA was associated with pain, physical function, mental function, and skin severity score. PGA distinguished different levels of severity well, as determined by comparison with different known groups with large effect sizes. CONCLUSION: Judged on an NRS, the PGA had good construct validity and satisfactorily distinguished all levels of severity in PsA.

Evaluation of spinal mobility measurements in predicting axial psoriatic arthritis.

Axial psoriatic arthritis (PsA) represents a more severe form of disease than peripheral PsA. We evaluate the usefulness of various spinal mobility measurements in predicting a radiographically defined axial PsA. A cross-sectional study on PsA patients with spinal mobility measurement performed. PsA were classified to axial or peripheral PsA by the presence of sacroiliitis. Three Bath Ankylosing Spondylitis Metrology Indexes (BASMIs) were calculated. The sensitivity, specificity, and area under receiver operator curves (AUC) of each spinal mobility measurement in prediction of axial PsA were analyzed. A total of 125 subjects studied (males 52%) with mean age and duration of illness of 47.5 ± 12.4 and 9.2 ± 6.7 years. Twenty-nine patients (17 males and duration of illness 12 females) had axial PsA. Axial PsA patients had longer disease duration (p = 0.05) and more limitation in spinal mobility. Axial PsA patients had higher inflammatory markers and a trend towards poorer global health, higher damaged joint count, and poorer physical function. The tragus-to-wall distance, modified schober test, and lumber side flexion had good sensitivity and specificity in predicting axial PsA. In the logistic regression model, the lumbar side flexion (OR 0.82, 95% CI 0.72-0.92) was independently associated with axial PsA. All three sets of composite scores BASMI(2), BASMI(10), and BASMI (lin) had good prediction for axial PsA (AUC 0.619, 0.626, and 0.618). Spinal mobility measurements and BASMI were useful in differentiating axial and peripheral PsA. Lumber side flexion and modified schober test best differentiate axial and peripheral PsA.

Comparison of 4 functional indexes in psoriatic arthritis with axial or peripheral disease subgroups using Rasch analyses.

OBJECTIVE: Rasch item response theory analysis is essential in evaluating measurement tools in specific disease cohorts. We compared the performance of 4 functional indexes in patients with psoriatic arthritis (PsA) in axial or peripheral disease subgroups. METHODS: A cross-sectional study was performed in a single center. Functional outcomes assessed by the Health Assessment Questionnaire (HAQ), Bath Ankylosing Spondylitis Functional Index (BASFI), Dougados Functional Index (FI), and the physical functioning scale of the Medical Outcome Study Short-form 36 (SF-36-PF) were analyzed by the Rasch model for item fit, item separation, measurement span, and distribution properties. Patient subgroups with axial or peripheral disease were analyzed for differential item functioning (DIF). RESULTS: One hundred eight patients with PsA were assessed. The 4 functional indexes were highly correlated with each other and moderately correlated with patients' perception of health and pain scores. Floor effects were less marked in SF-36-PF. The 4 indexes satisfied the unidimensionality assumption of the Rasch model. HAQ and SF-36-PF had better information-weighted fit statistics (INFIT) and outlier-sensitive (OUTFIT) statistics. HAQ had the poorest item separation. SF-36-PF had the highest item separation (6.99), reliability (0.85), and the longest span of item threshold (9.03 logits). Only 1 and 2 items in BASFI and Dougados-FI had DIF in patients with sacroiliitis. CONCLUSION: HAQ, BASFI, Dougados-FI, and SF-36-PF provide unidimensional measures of functional disability in PsA. SF-36-PF was the best in terms of less floor effect, highest item separation, longest span of item threshold, and better distributional properties. BASFI and Dougados-FI behaved similarly in patients with and without sacroiliitis and conferred no superiority in patients with axial disease.