Long-term effectiveness of epidural steroid injections after new episodes of low back pain in older adults.

BACKGROUND: There is limited research on the long-term effectiveness of epidural steroid injections (ESI) in older adults despite the high prevalence of back and leg pain in this age group. We tested the hypotheses that older adults undergoing ESI, compared to patients not receiving ESI: (1) have worse pain, disability and quality of life ('outcomes') pre-ESI, (2) have improved outcomes after ESI and (3) have improved outcomes due to a specific ESI effect. METHODS: We prospectively studied patients ≥65 years old presenting to primary care with new episodes of back pain in three US healthcare systems (BOLD registry). Outcomes were leg and back pain intensity, disability and quality of life, assessed at baseline and 3-, 6-, 12- and 24-month follow-ups. We categorized participants as: (1) ESI within 6 months from the index visit (n = 295); (2) no ESI within 6 months (n = 4809); (3) no ESI within 6 months, propensity-score matched to group 1 (n = 483). We analysed the data using linear regression and Generalized Estimating Equations. RESULTS: Pain intensity, disability and quality of life at baseline were significantly worse at baseline in ESI patients (group 1) than in group 2. The improvement from baseline to 24 months in all outcomes was statistically significant for group 1. However, no statistically significant differences were observed between outcome trajectories for the propensity-score matched groups 1 and 3. CONCLUSIONS: Older adults treated with ESI have long-term improvement. However, the improvement is unlikely the result of a specific ESI effect. SIGNIFICANCE: In this large, two-year, prospective study in older adults with a new episode of low back pain, back pain, leg pain, disability and quality of life improved after epidural steroid injections; however, propensity-score matching revealed that the improvement was unlikely the result of a specific effect of the injections, indicating that epidural steroids are unlikely to provide long-term benefits in older adults with new episodes of back and leg pain.

Providing Epidemiological Data in Lumbar Spine Imaging Reports Did Not Affect Subsequent Utilization of Spine Procedures: Secondary Outcomes from a Stepped-Wedge Randomized Controlled Trial.

OBJECTIVE: To evaluate the effect of inserting epidemiological information into lumbar spine imaging reports on subsequent nonsurgical and surgical procedures involving the thoracolumbosacral spine and sacroiliac joints. DESIGN: Analysis of secondary outcomes from the Lumbar Imaging with Reporting of Epidemiology (LIRE) pragmatic stepped-wedge randomized trial. SETTING: Primary care clinics within four integrated health care systems in the United States. SUBJECTS: 238,886 patients ≥18 years of age who received lumbar diagnostic imaging between 2013 and 2016. METHODS: Clinics were randomized to receive text containing age- and modality-specific epidemiological benchmarks indicating the prevalence of common spine imaging findings in people without low back pain, inserted into lumbar spine imaging reports (the "LIRE intervention"). The study outcomes were receiving 1) any nonsurgical lumbosacral or sacroiliac spine procedure (lumbosacral epidural steroid injection, facet joint injection, or facet joint radiofrequency ablation; or sacroiliac joint injection) or 2) any surgical procedure involving the lumbar, sacral, or thoracic spine (decompression surgery or spinal fusion or other spine surgery). RESULTS: The LIRE intervention was not significantly associated with subsequent utilization of nonsurgical lumbosacral or sacroiliac spine procedures (odds ratio [OR] = 1.01, 95% confidence interval [CI] 0.93-1.09; P = 0.79) or any surgical procedure (OR = 0.99, 95 CI 0.91-1.07; P = 0.74) involving the lumbar, sacral, or thoracic spine. The intervention was also not significantly associated with any individual spine procedure. CONCLUSIONS: Inserting epidemiological text into spine imaging reports had no effect on nonsurgical or surgical procedure utilization among patients receiving lumbar diagnostic imaging.

A targeted systematic review of cost analyses for implementation of simulation-based education in healthcare.

Over the past two decades, there has been an increase in the use of simulation-based education for training healthcare providers in technical and non-technical skills. Simulation education and research programs have mostly focused on the impact on clinical knowledge and improvement of technical skills rather than on cost. To study and characterize existing evidence to inform multi-stakeholder investment decisions, we performed a systematic review of the literature on costs in simulation-based education in medicine in general and in neonatal resuscitation as a particular focus. We conducted a systematic literature search of the PubMed database using two targeted queries. The first searched for cost analyses of healthcare simulation-based education more broadly, and the second was more narrowly focused on cost analyses of neonatal resuscitation training. The more general query identified 47 qualified articles. The most common specialties for education interventions were surgery (51%); obstetrics, gynecology, or pediatrics (11%); medicine, nursing, or medical school (11%); and urology (9%), accounting for over 80% of articles. The neonatal resuscitation query identified five qualified articles. The two queries identified seven large-scale training implementation studies, one in the United States and six in low-income countries. There were two articles each from Tanzania and India and one article each from Zambia and Ghana. Methods, definitions, and reported estimates varied across articles, implying interpretation, comparison, and generalization of program effects are challenging. More work is needed to understand the costs, processes, and outcomes likely to make simulation-based education programs cost-effective and scalable. To optimize return on investments in training, assessing resource requirements, associated costs, and subsequent outcomes can inform stakeholders about the potential sustainability of SBE programs. Healthcare stakeholders and decision makers will benefit from more transparent, consistent, rigorous, and explicit assessments of simulation-based education program development and implementation costs in low- and high-income countries.

Clinical and Payer-Based Analysis of Value of Dual-Energy Computed Tomography for Workup of Incidental Abdominal Findings.

OBJECTIVE: To perform a clinical and payer-based analysis of the value of dual-energy computed tomography (DECT) for workup of incidental abdominal findings. METHODS: This was a single-center, retrospectively designed, Health Insurance Portability and Accountability Act-compliant study approved by our institutional review board. Sixty-nine examinations in 69 patients (45 men, 24 women; mean age, 57.7 years) who underwent single-phase postcontrast abdominal DECT studies between January 1, 2011, and December 31, 2017, were included. Two radiologists, blinded to study objective and design, reviewed all cases and identified incidental abdominal findings needing further imaging. All incidental findings were reviewed by 2 other investigators, who determined whether an imaging-based diagnosis could be made using DECT virtual noncontrast images and iodine maps. Additional studies and associated payer-reimbursement amounts avoided by use of DECT were estimated. All imaging costs were estimated based on the US Centers for Medicare & Medicaid Services reimbursement amounts. RESULTS: Thirty-four incidental findings (renal mass, n = 20; adrenal nodule, n = 8; pancreatic cystic lesions, n = 3; others, n = 3) were identified in 19 (27.5%) of 69 patients. Dual-energy computed tomography characterized 27 incidental findings in 15 patients and accounted for cost savings of 15 additional imaging examinations (abdominal magnetic resonance imaging, n = 11; abdominal computed tomography, n = 4). Based on Centers for Medicare & Medicaid Services reimbursement amounts, we estimated that, by abolishing the need for additional imaging use, DECT saved US $84.95 per patient. CONCLUSIONS: Dual-energy computed tomography can provide an imaging-based diagnosis of incidental abdominal findings, otherwise incompletely characterized on routine abdominal computed tomography, in approximately 21% of patients. In select patients, the monetary savings from abolishing additional imaging may reduce payer costs associated with use of DECT.

Imaging Intussusception in Children's Hospitals in the United States: Trends, Outcomes, and Costs.

OBJECTIVE: To describe imaging utilization, outcomes, and cost in the management of intussusception between 2010 and 2017 in pediatric hospitals in the United States. METHODS: All children (under 18 years of age) with a primary diagnosis of intussusception in a large administrative database were identified. Demographics, imaging, and costs were described. RESULTS: There were 17,032 children (63.3% boys, 36.7% girls, mean age: 3.2 years) that had 20,655 hospital encounters for intussusception, and 88.5% were <5 years of age. The average length of stay was 2.8 days (median: 1 day), with rates of intensive care unit admission, 3.7%; 90-day readmission, 10.5%; and mortality, 0.2%. The surgical rate was 19.6%, and 93.5% (n = 19,301) of patients underwent imaging: 87.2% (n = 16,822) received ultrasound, 69.1% (n = 13,329) had fluoroscopy, 59% (n = 11,380) had abdominal radiographs, and 8.8% (n = 1,696) had CT. The reduction success rate for fluoroscopy was 77.9%. Surgery was more common in rural patients (26.8% versus 18.7% in urban patients, P < .001). Median encounter costs were $2,675 (interquartile range: $1,637-$5,465). Imaging cost represented a quarter (median $680, interquartile range: $372-1,069) of all costs. Higher costs (median) were associated with longer length of stay (<3 days: $858 versus >3 days: $5,342; use of CT ($4,168 versus $943 in patients without a CT), and surgery ($4,434 versus $860 without surgery). CONCLUSION: The management of intussusception is mainly nonsurgical, most frequently involving imaging with ultrasound and fluoroscopy, and resulting in excellent outcomes in the great majority of the cases. Despite playing a central role for diagnosis and management, imaging only represents a fraction of total cost.

Impact of co-morbidities on resource use and adherence to guidelines among commercially insured adults with new visits for back pain.

RATIONALE, AIMS AND OBJECTIVES: To assess if co-morbidity is associated with higher use of back-related care and adherence to back pain guidelines. METHODS: We conducted a retrospective cohort study using administrative claims data from 2007-2011. We included individuals ≥18 years with an index visit for back pain. Co-morbidities were measured 12 months prior to index. Co-morbidity burden was measured using Quan's Co-morbidity Index. Co-morbidities categories were measured using chronic condition indicators from the Agency for Healthcare Research and Quality. Total lumbar spine-related resource use for three years was ascertained using procedure codes. A clustering algorithm identified higher long-term utilizer. We identified initial use from day 0-42 for several categories of spine-related care. We used logistic regression to test the association between co-morbidities and resource use. RESULTS: Greater co-morbidity burden was associated with higher long-term spine-related resource use. Those with ≥2 on Quan's Co-morbidity Index had 29% higher odds of being a high back-specific resource user compared to those with no co-morbidities [Odds Ratio (OR): 1.29, 95% Confidence Interval (CI): 1.23-1.35]. Greater co-morbidity burden was associated with more frequent initial use of imaging, emergency visits, injections, and opioid fills; and less frequent initial use of medical and physical therapy visits. Co-morbid musculoskeletal conditions had the strongest association with being a high utilizer of long-term back-specific resources (OR: 1.53, 95% CI: 1.50-1.57). CONCLUSIONS: Co-morbidity burden and the presence of specific chronic conditions, such as musculoskeletal conditions, were associated with high long-term use of back-related care and care inconsistent with guidelines.

Including patient-reported outcomes and patient-reported resource-use questionnaires in studies.

RATIONALE: More efficient and better informed healthcare systems are expected to have improved knowledge of the impact of interventions on patient outcomes and resources used by patients and providers in specific health conditions. OBJECTIVES: To describe trends related to putting patients at the center of healthcare decision making, regulatory trends and best practice recommendations for developing high-quality patient-reported outcomes (PROs), and strategic issues related to including PROs in studies. MATERIALS AND METHODS: We summarize PRO concepts, definitions, and broadly-accepted scientific standards for developing, assessing, and interpreting PROs. Three conceptual models are presented as examples for assessing PROs in relation to other outcomes. We discuss different perspectives for stakeholders, including regulatory issues pertaining to formal guidance for PRO development and for use in trials. We provide examples of PROs used in studies for assessing health outcomes in oncology and resource-use outcomes in low back pain patients. RESULTS: Psychometric scientists working closely with multi-disciplinary teams and regulatory authorities have greatly improved the science of collecting, assessing, and understanding patient-reported outcomes in clinical trials. A simplified framework is presented for strategic considerations for including PROs in studies, such as the appropriate timing for PRO endpoints. Asking patients about their health status and/or use of resources improves our understanding of how interventions and care processes may impact their lives and their budgets. We provide examples from a back pain trial of patient-reported resource-use questionnaires for medicines taken and other services or products used by patients. CONCLUSIONS: Healthcare stakeholders are placing increased emphasis on resource use and the impact of interventions on patients, including effects associated with diagnostic tests. Patient-reported outcomes are being used in clinical practice and in clinical research, supported by formal best-practice guidelines. Radiology has a role as an engaged stakeholder in the design, conduct, and interpretation of patient-based evidence, and in its relevance to health policy implementation.

Systematic review of comparative effectiveness data for oncology orphan drugs.

OBJECTIVES: To systematically assess clinical and economic evidence for oncology orphan drugs marketed in the United States and to highlight the challenges and opportunities for evidence development within this pharmaceutical category. STUDY DESIGN: Systematic review. METHODS: We conducted systematic literature searches of the Medline and Embase databases for clinical and cost-effectiveness studies published before June 2010 for all oncology orphan drugs marketed in the United States. We used the Grading of Recommendations Assessment, Development and Evaluation method and the Quality of Health Economic Studies criteria to assess the quality of the selected studies. RESULTS: We identified 60 randomized controlled trials and 21 cost-effectiveness analyses to support 47 oncology orphan drugs. A total of 21 drugs had moderate or high-quality bodies of clinical evidence, 11 had low-quality or very low quality clinical evidence, and 15 drugs could not be evaluated because we were unable to identify clinical evidence that met our inclusion criteria. The Spearman rank correlation coefficient for the level of evidence for oncology orphan drugs and disease prevalence was 0.3 (95% confidence interval, 0.0-0.5). The cost-effectiveness analyses received quality scores between 72 and 100 (range 0-100), with a mean score of 85. CONCLUSIONS: The results of our study show that oncology orphan drugs marketed in the United States have varying levels and quality of clinical evidence and a paucity of evidence regarding economic value. Innovative analytic and policy approaches are needed to develop and implement a decision-making framework for this pharmaceutical category that is consistent with evidence-based medicine and comparative effectiveness research.

Study protocol- Lumbar Epidural steroid injections for Spinal Stenosis (LESS): a double-blind randomized controlled trial of epidural steroid injections for lumbar spinal stenosis among older adults.

BACKGROUND: Lumbar spinal stenosis is one of the most common causes of low back pain among older adults and can cause significant disability. Despite its prevalence, treatment of spinal stenosis symptoms remains controversial. Epidural steroid injections are used with increasing frequency as a less invasive, potentially safer, and more cost-effective treatment than surgery. However, there is a lack of data to judge the effectiveness and safety of epidural steroid injections for spinal stenosis. We describe our prospective, double-blind, randomized controlled trial that tests the hypothesis that epidural injections with steroids plus local anesthetic are more effective than epidural injections of local anesthetic alone in improving pain and function among older adults with lumbar spinal stenosis. METHODS: We will recruit up to 400 patients with lumbar central canal spinal stenosis from at least 9 clinical sites over 2 years. Patients with spinal instability who require surgical fusion, a history of prior lumbar surgery, or prior epidural steroid injection within the past 6 months are excluded. Participants are randomly assigned to receive either ESI with local anesthetic or the control intervention (epidural injections with local anesthetic alone). Subjects receive up to 2 injections prior to the primary endpoint at 6 weeks, at which time they may choose to crossover to the other intervention.Participants complete validated, standardized measures of pain, functional disability, and health-related quality of life at baseline and at 3 weeks, 6 weeks, and 3, 6, and 12 months after randomization. The primary outcomes are Roland-Morris Disability Questionnaire and a numerical rating scale measure of pain intensity at 6 weeks. In order to better understand their safety, we also measure cortisol, HbA1c, fasting blood glucose, weight, and blood pressure at baseline, and at 3 and 6 weeks post-injection. We also obtain data on resource utilization and costs to assess cost-effectiveness of epidural steroid injection. DISCUSSION: This study is the first multi-center, double-blind RCT to evaluate the effectiveness of epidural steroid injections in improving pain and function among older adults with lumbar spinal stenosis. The study will also yield data on the safety and cost-effectiveness of this procedure for older adults. TRIAL REGISTRATION: Clinicaltrials.gov NCT01238536.

Economic evaluation in radiology: reviewing the literature and examples in oncology.

RATIONALE AND OBJECTIVES: To review US health care trends related to medical imaging utilization and costs as well as to present standard methods for conducting economic evaluation for health care interventions and medical imaging specifically. MATERIALS AND METHODS: A review of the medical literature was performed to assess health policy and health technology assessment trends, expenditures, and cost-effectiveness analysis (CEA) related to medical imaging. Standard approaches to conducting economic evaluation and cost-effectiveness analysis were reviewed and summarized. Examples of CEA evidence related to imaging in select oncology conditions were presented. RESULTS: Several high-quality methodology publications have provided guidance for conducting economic evaluation and CEA in radiology. There is variability in the quality of CEA models and their dissemination. However, there are numerous methodologically sound cost-effectiveness analyses for radiology procedures, and the evidence base of CEA studies for medical imaging continues to increase. Advanced imaging approaches for diagnosing and staging oncology conditions have the potential to provide cost-effective care when used in appropriate patient subpopulations. CONCLUSIONS: Additional rigorous comparative effectiveness studies for advanced imaging, including cost-effectiveness analyses, can provide useful information to policy makers and health care providers on the relative effects and costs associated with diagnostic alternatives.

Impact of efalizumab on psoriasis-specific patient-reported outcomes. Results from three randomized, placebo-controlled clinical trials of moderate to severe plaque psoriasis.

The objective of this study was to document the disease burden associated with moderate to severe plaque psoriasis, and assess the impact of efalizumab psoriasis treatment in improving patient-reported outcomes. This included analysis of patient-reported dermatology-related quality of life (DRQL) and psoriasis symptom scores among patients with moderate to severe psoriasis participating in three phase III, randomized, double-blinded, parallel-group, placebo-controlled, multi-center clinical trials conducted to evaluate the efficacy and safety of efalizumab. A total of 1,242 patients with moderate to severe psoriasis treated either with efalizumab 1.0 mg/kg/wk or placebo were followed for 12 weeks. DRQL and psoriasis symptom severity were assessed at baseline (pre-treatment) and at the end of the first treatment phase (12 weeks). DRQL was measured using the Dermatology Life Quality Index (DLQI). Symptoms were measured using the Psoriasis Symptom Assessment (PSA) and an Itch scale. Disease burden was assessed at baseline by examining responses to individual questions of the DLQI, PSA, and Itch patient-reported outcome measures. The impact of treatment on disease burden was assessed over a 12-week double-blind study period by comparing changes in DLQI, PSA, and Itch scale scores between the active treatment and placebo groups. Patient-reported outcomes were also assessed during a 12-week extended treatment phase. Prior to treatment, the responses to DLQI and PSA items revealed significant disease burden. Greater than 90% of patients reported being embarrassed or self conscious because of their skin, 53% reported that their skin prevented them from working or studying. and 98% reported that scaling and itching was bothersome. Compared to placebo-treated patients, efalizumab-treated patients showed significant improvement in patient-reported outcomes, reducing the limitations and burden associated with moderate to severe psoriasis within each of the three studies, as measured by DLQI (p<0.001), PSA-Severity (p<0.001), PSA-Frequency (p<0.001), and Itch (p<0.001) scores. Across all measures, the proportion of patients that improved on both statistical and clinical criteria for meaningful improvement was at least twofold greater among efalizumab-treated patients than in placebo-treated patients. The benefit of efalizumab was maintained over the course of an additional 12 weeks during an extended treatment phase. In conclusion, patients with moderate to severe plaque psoriasis reported significant DRQL burden and symptom severity at baseline, but efalizumab significantly improved patient-reported DRQL and reduced the frequency and severity of psoriasis symptoms during 12-week double-blind and 12-week extended treatment periods.

The burden of illness associated with psoriasis: cost of treatment with systemic therapy and phototherapy in the US.

OBJECTIVE: To evaluate utilization and direct healthcare expenditures among psoriasis patients treated with systemic therapy and phototherapy in the United States. DESIGN: Cohort study using retrospective administrative medical claims. PATIENTS: Psoriasis patients treated with systemic therapy and phototherapy, as well as a matched cohort of non-psoriasis patients. All patients were covered by employer-sponsored insurance between 1 April 1996 and 31 December 2000. MAIN OUTCOME MEASURES: Estimated risk of hospitalization and total annual healthcare expenditures overall and by comorbidity status were compared for persons with psoriasis using systemic therapy or phototherapy and persons without psoriasis. Annualized utilization rates for hospitalizations, and use of emergency department, outpatient physician, outpatient laboratory, and outpatient pharmaceutical services were also compared across the two cohorts. RESULTS: Seventeen percent of psoriasis patients were treated with systemic therapy or phototherapy. Patients with comorbid anemia, carcinoma, diabetes, depression, GI disorders, hepatotoxicity, hypertension, and nephrotoxicity had significantly higher expenditures than non-psoriasis patients with the same comorbidities (p < or =0.05). Elevated risk of hospitalization also contributed to higher expenditures in patients treated with systemic therapy or phototherapy. Limitations of this study include those inherent in using claims data such as dependence on diagnosis coding, the fact that psoriasis severity cannot be determined directly from claims data, confounding comorbidities, and the fact that only direct healthcare expenditures were considered in this analysis. CONCLUSION: Psoriasis patients treated with systemic therapies/phototherapies have significantly more comorbidities and higher mean total healthcare expenditures compared to non-psoriasis patients. Psoriasis patients with selected comorbidities have significantly higher mean total healthcare expenditures compared to non-psoriasis persons with the same comorbidities.

Efalizumab for patients with moderate to severe plaque psoriasis: a randomized controlled trial.

CONTEXT: Because T-cell interactions are involved in the pathophysiology of psoriasis, therapy with a T-cell modulator may have beneficial effects on psoriasis severity and health-related quality of life (HRQL). OBJECTIVE: To assess the efficacy and safety of efalizumab, a T-cell modulator, in patients with plaque psoriasis. DESIGN, SETTING, AND PATIENTS: Phase 3 randomized, double-blind, parallel-group, placebo-controlled trial involving 556 adult patients with stable, moderate to severe plaque psoriasis and conducted at 30 study centers in the United States and Canada between January and July 2002. INTERVENTIONS: Patients were randomly assigned in a 2:1 ratio to receive 12 weekly doses of subcutaneous efalizumab, 1 mg/kg (n = 369), or placebo equivalent (n = 187). MAIN OUTCOME MEASURES: At least 75% improvement on the Psoriasis Area and Severity Index (PASI-75); improvement on the overall Dermatology Life Quality Index (DLQI), Itching Visual Analog Scale (VAS), and Psoriasis Symptom Assessment (PSA) at week 12 vs baseline. RESULTS: Efalizumab-treated patients experienced significantly greater improvement on all end points than placebo-treated patients. Twenty-seven percent of efalizumab-treated patients achieved PASI-75 vs 4% of the placebo group ( P<.001). Efalizumab-treated patients exhibited significantly greater mean percentage improvement than placebo-treated patients on the overall DLQI (47% vs 14%; P<.001), Itching VAS (38% vs -0.2%; P<.001), and PSA frequency and severity subscales (48% vs 18% and 47% vs 17%, respectively; P<.001 for both) at the first assessment point. Efalizumab was safe and well tolerated, with primarily mild to moderate adverse events. CONCLUSION: In this 12-week study, efalizumab resulted in significant improvements in clinical end points, including physician-assessed and dermatology-specific patient-reported HRQL measures, in patients with moderate to severe plaque psoriasis.

Validity and reliability of patient reported outcomes used in psoriasis: results from two randomized clinical trials.

BACKGROUND: Two Phase III randomized controlled clinical trials were conducted to assess the efficacy, safety, and tolerability of weekly subcutaneous administration of efalizumab for the treatment of psoriasis. Patient reported measures of psoriasis-related functionality and health-related quality of life and of psoriasis-related symptom assessments were included as part of the trials. OBJECTIVE: To assess the reliability, validity, and responsiveness of the patient reported outcome measures that were used in the trials - the Dermatology Life Quality Index (DLQI), the Psoriasis Symptom Assessment (PSA) Scale, and two itch measures, a Visual Analog Scale (VAS) and the National Psoriasis Foundation (NPF) itch measure. METHODS: Subjects aged 18 to 70 years with moderate to severe psoriasis for at least 6 months were recruited into the two clinical trials (n = 1095). Internal consistency reliability was evaluated for all patient reported outcomes at baseline and at 12 weeks. Construct validity was evaluated by relations among the different patient reported outcomes and between the patient reported outcomes and the clinical assessments (Psoriasis Area and Severity Index; Overall Lesion Severity Scale; Physician's Global Assessment of Change) assessed at baseline and at 12 weeks, as was the change over the course of the 12 week portion of the trial. RESULTS: Internal consistency reliability ranged from 0.86 to 0.95 for the patient reported outcome measures. The patient reported outcome measures were all shown to have significant construct validity with respect to each other and with respect to the clinical assessments. The four measures also demonstrated significant responsiveness to change in underlying clinical status of the patients over the course of the trial, as measured by the independently assessed clinical outcomes. CONCLUSIONS: The DLQI, the PSA, VAS, and the NPF are considered useful tools for the measurement of dermatology-related limitations of functional ability and the frequency, severity and impact of psoriasis symptoms on patients' lives and psoriasis-related quality of life.