Floor effect

Abstract: OBJECTIVES: The objective was to examine whether the Oxford Hip Score (OHS) demonstrated a floor or a ceiling effect when used to measure the outcome of hip replacement surgery in a large national cohort. SETTING: Secondary database analysis of a national audit conducted in England and Wales on patient undergoing hip and knee arthroplasty in a secondary care setting. PARTICIPANTS: 93 253 primary arthroplasty patients completed preoperative OHS questionnaires and 69 361 completed 6-month postoperative OHS questionnaires. The population had a mean age of 67.78 (range 14-100, SD 11.3) and 59% were female. PRIMARY SECONDARY OUTCOME MEASURES: Primary outcome measure was the Oxford Hip Score (OHS). Secondary outcome measures were the OHS-FCS and OHS-PCS. Floor and ceiling effects were considered present if >15% of patients achieved the worst score/floor effect (0/48) or best/ceiling effect (48/48) score. RESULTS: Preoperatively, 0% of patients achieved the best score (48) and 0.1% achieved the worst score (0). Postoperatively, 0.1% patients achieved the worst score, but the percentage achieving the best score increased to 11.6%. Subgroup analyses demonstrated that patients between 50 and 59 years of age had the highest postoperative best score, at 15.3%. The highest postoperative OHS worst score percentage was in a group of patients who had a preoperative OHS above 41/48 at 28%. Furthermore, 22.6% of patients achieved the best postoperative OHS-PCS and 19.9% best postoperative OHS-FCS. CONCLUSIONS: Based on NHS PROMS data the overall OHS does not exhibit a ceiling or floor effect and should continue to be used as a valid measure of patient-reported outcomes for patients undergoing total hip arthroplasty. However, subscale analysis does indicate some limitations in the OHS-PCS and OHS-FCS. TRIAL REGISTRATION NUMBER: NDORMS. Introducing standardised and evidence-based thresholds for hip and knee replacement surgery. The Arthroplasty Candidacy Help Engine (ACHE tool). HTA Project 11/63/01.

Abstract: PURPOSE Patient-reported outcomes are important to assess effectiveness of clinical interventions. For orthopaedic trauma patients, the short Musculoskeletal Function Assessment (sMFA) is a commonly used questionnaire. Recently, the Patient-Reported Outcome Measurement Information System (PROMIS) PF Function Computer Adaptive Test (PF CAT) was developed using item response theory to efficiently administer questions from a calibrated bank of 124 PF questions using computerized adaptive testing. In this study, we compared the sMFA versus the PROMIS PF CAT for trauma patients. METHODS Orthopaedic trauma patients completed the sMFA and the PROMIS PF CAT on a tablet wirelessly connected to the PROMIS Assessment Center. The time for each test administration was recorded. A 1-parameter item response theory model was used to examine the psychometric properties of the instruments, including precision and floor/ceiling effects. RESULTS One hundred fifty-three orthopaedic trauma patients participated in the study. Mean test administration time for PROMIS PF CAT was 44 seconds versus 599 seconds for sMFA (P < 0.05). Both instruments showed extremely high item reliability (Cronbach alpha = 0.98). In terms of instrument coverage, neither instrument showed any floor effect; however, the sMFA revealed 14.4% ceiling effect, whereas the PROMIS PF CAT had no appreciable ceiling effect. CONCLUSIONS Administered by electronic means, the PROMIS PF CAT required less than one-tenth the amount of time for patients to complete than the sMFA while achieving equally high reliability and less ceiling effects. The PROMIS PF CAT is a very attractive and innovative method for assessing patient-reported outcomes with minimal burden to patients.

Abstract: Study design Patient-reported outcomes provide vital information when assessing effectiveness of clinical care. Yet, most patient-reported outcome instruments are limited by lack of validation and reliability to measure PF adequately. As part of the Patient-Reported Outcomes Measurement Information System (PROMIS), a PF item bank consisting of 124 items has been developed. Objective There is validation evidence for the PROMIS PF item bank in the general orthopedic patient population in general, but has yet to be validated in the patient with spinal disorders. This study aims to evaluate the psychometric properties of the PROMIS PF item bank specifically for patients presenting with spine-related complaints. Summary of background data Data were collected from adult patients visiting a university spine clinic for back and neck problems. All patients older than 18 years were eligible to participate. A total of 438 patients (49% male) were enrolled in this prospective study. Patients were 18- to 89-year old and presented with back problems (n = 286) and neck problems (n = 152). All patients were administered a 131 item questionnaire. Methods Conventional descriptive statistics such as means, standard deviations, and proportions were conducted to examine patient characteristics. A Rasch model was used to examine the psychometric properties of the instrument including dimensionality, floor/ceiling effects, reliabilities, and item bias. Results Results showed that a single PF dimension was supported by the data (i.e., unexplained variance was 2.9%). The instrument had 1.7% ceiling effect and 0.2% floor effect. Item reliability was 1.00 and person reliability was 0.99. We found evidence of item response bias associated with sex, age, and education in some items. Conclusion The PROMIS PF item bank adequately addressed outcomes of patients with spinal disorders as reliabilities were excellent, minimal ceiling/floor effect existed, and item bias was limited. Future effort should be focused on eliminating, rescaling, or modifying those items that had item bias. Level of evidence 2.

Abstract: BACKGROUND: Fear of falling scales typically have a strong floor effect in active people and use short phrases to state overall context of fear-related activities. We developed the Iconographical Falls Efficacy Scale (Icon-FES), which includes more demanding activities and uses pictures to provide more complete environmental contexts. METHODS: Two-hundred and fifty community-dwelling older people (70-90 years) were assessed on the Icon-FES in conjunction with the Falls Efficacy Scale International (FES-I). RESULTS: Overall structure and measurement properties of the 30-item Icon-FES (evaluated with item-response theory) were good. It measured a single factor with 2 dimensions assessing fear about less and more demanding daily activities. It had high internal consistency (Cronbach's alpha = 0.96) and excellent test-retest reliability. The Icon-FES distribution was considerably closer to normal compared with FES-I, indicating absence of floor and ceiling effects. Construct validity of the Icon-FES was supported by its relation with FES-I and its ability to discriminate between groups relating to demographic characteristics and fall risk factors. A shortened 10-item Icon-FES showed similar psychometric properties to the 30-item Icon-FES. CONCLUSIONS: The Icon-FES is an innovative way of assessing fear of falling using pictures to describe a range of activities and situations. This initial validation study showed that the Icon-FES has excellent psychometric properties and showed close continuity with the FES-I. Main advantages of the Icon-FES over the FES-I are its normal distribution and its ability to assess fear of falling in high functioning older people. Language: en