Use of Rasch analysis to refine a patient-reported questionnaire on satisfaction with communication of the multiple sclerosis diagnosis.

BACKGROUND: The Comunicazione medico-paziente nella Sclerosi Multipla - Revised (COSM-R) is a patient self-assessed questionnaire probing the moment of multiple sclerosis (MS) diagnosis disclosure (section 1, five items) and following period (section 2, 15 items). OBJECTIVES: This study examined COSM-R dimensionality and measurement properties through Rasch analysis (partial-credit model) and proposed a revised questionnaire. METHODS: Cross-sectional COSM-R data were obtained from 1068 people with MS (PwMS, 1065 questionnaires) participating in four studies (102 centres). Mean age was 40 years (range 17-73); 70% were women; 53% were from Northern, 25% from Central, and 21% from Southern Italy. RESULTS: Unidimensionality was not confirmed for COSM-R section 1, but was for section 2 after removal of three items. The revised instrument (COSM-S, Shortened) consisted of the original five-item checklist (section 1), modified by removing the table grouping of three items, and 12 of the original 15 section 2 items, which could now be summed and transformed into an interval scale. Scores were higher for items assessing emotional satisfaction than for those assessing informational satisfaction. CONCLUSIONS: The proposed COSM-S is a composite measure of satisfaction with MS diagnosis communication with improved metric properties over the original COSM-R, and whose section 2 satisfies Rasch model expectations.

The Royal College of Ophthalmologists' National Ophthalmology Database Study of cataract surgery. Report 5: Clinical outcome and risk factors for posterior capsule rupture and visual acuity loss following cataract surgery in patients aged 90 years and older.

BACKGROUND: Older age is commonly associated with an increased risk of surgical complications and comparatively poor outcomes. PURPOSE: To report cataract surgery outcomes and risk indicators for patients aged 90 years and older. METHODS: Data collected as part of routine cataract care in 34 centres contributing to the United Kingdom Royal College of Ophthalmologists' National Ophthalmology Database (NOD) were analysed. Very elderly people undergoing cataract surgery were profiled in terms of demographics, pre- and postoperative best-measured visual acuity (VA), ocular co-morbidities, intraoperative posterior capsule rupture (PCR) or vitreous loss or both, and risk indicators for operative PCR and adverse VA outcome. RESULTS: 25,856 cataract operations in 19,166 people of 90 years or older between 2000 and 2014 are reported. Preoperative VA was available for 82.4% eyes, being 0.30 LogMAR or better in 21.5%. Postoperative VA was available for 61.8% eyes, being 0.30 LogMAR or better in 74.4%. For those without ocular co-morbidity, postoperative VA was 0.30 LogMAR or better in 84.7%. Various co-morbidities were present in 49% and contributed to an adverse VA outcome. PCR data were available for all operations and occurred in 2.7%. Significant risk indicators for PCR included pseudoexfoliation/phakodonesis, mature cataract, smaller pupil and worse preoperative VA. CONCLUSIONS: Slightly poorer cataract surgery outcome results were noted in patients of 90 years or older, more so in patients with ocular co-morbidity which was highly prevalent. However, surgeons should not be deterred from offering cataract surgery to the very elderly as successful visual rehabilitation remains achievable.

Cataract surgery patient-reported outcome measures: a head-to-head comparison of the psychometric performance and patient acceptability of the Cat-PROM5 and Catquest-9SF self-report questionnaires.

Background Cataract surgery is the most frequently undertaken NHS surgical procedure. Visual acuity (VA) provides a poor indication of visual difficulty in a complex visual world. In the absence of a suitable outcome metric, recent efforts have been directed towards the development of a cataract patient-reported outcome measure (PROM) of sufficient brevity, precision, and responsiveness to be implementable in routine high volume clinical services.Aim To compare and contrast the two most promising candidate PROMs for routine cataract surgery.Method The psychometric performance and patient acceptability of the recently UK developed five-item Cat-PROM5 questionnaire was compared with the English translation of the Swedish nine-item Catquest-9SF using Rasch-based performance metrics and qualitative semistructured interviews.Results Rasch-based performance was assessed in 822 typical NHS cataract surgery patients across four centres in England. Both questionnaires demonstrated good to excellent performance for all metrics assessed, including Person Reliability Indices of 0.90 (Cat-PROM5) and 0.88 (Catquest-9SF), responsiveness to surgery (Cohen's standardized effect size) of 1.45 SD (Cat-PROM5) and 1.47 SD (Catquest-9SF) and they were highly correlated with each other (R=0.85). Qualitative assessments confirmed that both questionnaires were acceptable to patients, including in the presence of ocular comorbidities. Preferences were expressed for the shorter Cat-PROM5, which allowed patients to map their own issues to the questions as opposed to the more restrictive specific scenarios of Catquest-9SF.Conclusion The recently UK developed Cat-PROM5 cataract surgery questionnaire is shorter, with performance and patient acceptability at least as good or better than the previous 'best of class' Catquest-9SF instrument.

Cat-PROM5: a brief psychometrically robust self-report questionnaire instrument for cataract surgery.

PurposeTo develop a short, psychometrically robust and responsive cataract patient reported outcome measure suitable for use in high-volume surgical environments.MethodsA prospective study in which participants completed development versions of questionnaires exploring the quality of their eyesight using items harvested from two existing United Kingdom developed parent questionnaires. Participants were 822 patients awaiting cataract surgery recruited from 4 cataract surgical centres based in the UK. Exclusion criteria were other visually significant comorbidities and age <50 years. An iterative multi-stage process of evaluation using Rasch and factor analyses with sequential item reduction was undertaken.ResultsA definitive item set of just five items delivered performance in accordance with the requirements of the Rasch model: no threshold disordering, no misfitting items, Rasch-based reliability 0.90, person separation 2.98, Cronbach's α 0.89, good targeting of questions to patients with cataract with pre-operative item mean -0.41 logits and absence of significant floor or ceiling effects, minor deviations of item invariance, and confirmed unidimensionality. The test-re-test repeatability intra-class correlation coefficient was 0.89 with excellent responsiveness to surgery, Cohen's d -1.45 SD. Rasch calibration values are provided for Cat-PROM5 users.ConclusionsA psychometrically robust and highly responsive five-item cataract surgery patient reported outcome measure has been developed, which is suitable for use in high-volume cataract surgical services.