Evaluation of symptoms in respiratory syncytial virus infection in adults: psychometric evaluation of the Respiratory Infection Intensity and Impact Questionnaire™ symptom scores.

BACKGROUND: The Respiratory Infection Intensity and Impact Questionnaire (RiiQ™) is a patient-reported outcome measure designed to assess symptoms and impacts of respiratory syncytial virus (RSV) infection. This study evaluated the construct validity, reliability, and responsiveness of the RiiQ™ Respiratory and Systemic Symptoms Scale scores. METHODS: Prospective data were analyzed from a total of 1795 participants, including from non-hospitalized patients with acute respiratory infection (ARI) and no coinfections enrolled in a Phase 2b RSV vaccine study (RSV-positive: n = 60; RSV-negative: n = 1615), and two observational studies of patients hospitalized with RSV (n = 20; n = 100). Descriptive statistics, confirmatory factor analysis (CFA), test-retest intraclass correlation coefficients (ICCs), construct validity correlations (between a clinician-assessed clinical questionnaire and the RiiQ™ symptoms scale), known-groups validity, and responsiveness (correlations of change scores) were evaluated. RESULTS: Mean patient age ranged from 66.5 to 71.5 years and the majority of patients were female. Initial assessments in the vaccine trial (ARI Day 1) were suggestive of less severe illness than in the observational studies with hospitalized patients. CFA loadings (> 0.40) supported summary scores. ICCs exceeding the recommended threshold of 0.70 supported test-retest reliability for Respiratory and Systemic Symptoms, except in the small observational study. At the scale level, correlations were moderate to strong (|r| ≥ 0.3) and positive between the Respiratory Symptoms Scale and the related clinical questionnaire scores, reflecting measurement of similar symptoms in support of convergent validity. Correlations with change in Patient Global Impression of Severity > 0.30 supported responsiveness. CONCLUSIONS: Psychometric tests applied to the RiiQ™ Symptoms scales provide evidence of its reliability, construct validity, discriminating ability, and responsiveness for use in clinical studies to assess the onset and severity of RSV symptoms.

Assessment of craving in opioid use disorder: Psychometric evaluation and predictive validity of the opioid craving VAS.

BACKGROUND: This work evaluated the psychometric properties of the single-item Opioid Craving Visual Analog Scale (OC-VAS) for opioid use disorder (OUD). METHODS: Psychometric evaluation of the OC-VAS (range: 0-100 mm) was supported by Subjective Opiate Withdrawal Scale (SOWS) item 16 and total score, Clinical Opiate Withdrawal Scale (COWS) scores, and the 36-Item Short-Form Health Survey, using data from phase 3 study (NCT02357901; N = 487) participants who received randomized treatment and completed the OC-VAS at screening. Descriptive properties, test-retest reliability, construct validity, known-groups validity, and responsiveness were assessed. Interpretation of meaningful change and predictive validity were also explored. RESULTS: Descriptive properties for the OC-VAS at screening did not provide evidence of problematic floor/ceiling effects or missingness. The test-retest reliability was established by weekly intraclass correlations >0.70. At the screening and end of the study, the strong positive correlations between OC-VAS and SOWS Total/Item 16 score and the significant OC-VAS differences among COWS severity groups supported construct validity and known-groups (discriminating ability) validity, respectively. The associations between the changes in OC-VAS and in supporting measures/opioid use from screening to the end of the study demonstrated responsiveness and the ability to detect change in clinical status. During the induction and randomization treatment periods, significant relationships were identified between OC-VAS score and subsequent opioid use. CONCLUSIONS: This psychometric evaluation of the OC-VAS performed on a large OUD patient population provides evidence to support its use to measure the severity of opioid craving and its ability to predict opioid use.

Development, psychometric evaluation, and initial feasibility assessment of a symptom tracker for use by patients with heart failure (HFaST).

BACKGROUND: This study aimed to develop and provide a psychometric and feasibility pilot evaluation of the Heart Failure (HF) Symptom Tracker (HFaST), a new patient-reported tool designed to facilitate communication between patients and health care providers (HCPs) in routine clinical care. The HFaST enables patients to identify worsening HF symptoms, with a long-term goal of preventing hospitalizations or emergency room visits. METHODS: The HFaST was developed drawing on evidence from the literature, qualitatively with cognitive interviews (12 patient/caregiver and 8 HCPs), and evaluated quantitatively (psychometric, feasibility assessment). The HFaST was administered for 7 consecutive days to 100 individuals diagnosed with HF during a multisite, non-interventional US pilot study. Health care providers then completed a survey assessing the feasibility and importance of the HFaST in clinical practice. Qualitative development included a literature review and cognitive interviews with patients, caregivers, and HCPs. The psychometric properties of the HFaST were evaluated using classical test theory methods. Descriptive statistics provided insight into HCPs' perceptions of the feasibility of using the HFaST in clinical practice. RESULTS: A preliminary set of 40 items was developed for the symptom tracker and iteratively reduced to 10 items based on the qualitative phase. Test-retest reliability (weighted kappa 0.71-0.97), discriminating validity, and construct validity of the HFaST were acceptable. HCPs rated the HFaST as a good (70%) or excellent (30%) means of tracking HF symptoms. Six HFaST items were ultimately retained, covering concepts of fatigue, shortness of breath (3 items), swelling, and rapid weight gain. CONCLUSIONS: The 6-item HFaST is an easy-to-use tool designed to raise patients' awareness of HF symptoms and facilitate communication with HCPs. Future research should evaluate HFaST implementation in clinical practice and effectiveness as an intervention to potentially prevent hospitalizations and emergency room visits.

Long-term health-related quality-of-life and symptom response profiles with arformoterol in COPD: results from a 52-week trial.

Background: Symptom severity is the largest factor in determining subjective health in COPD. Symptoms (eg, chronic cough, dyspnea) are associated with decreased health-related quality of life (HRQoL). We evaluated the impact of arformoterol on HRQoL in COPD patients, measured by St George's Respiratory Questionnaire (SGRQ). Post hoc growth mixture model (GMM) analysis examined symptom response profiles. Methods: We examined data from a randomized, double-blind, parallel-group, 12-month safety trial of twice-daily nebulized arformoterol 15 µg (n=420) versus placebo (n=421). COPD severity was assessed by Global Initiative for Chronic Obstructive Lung Disease (GOLD) status. GMM analysis identified previously unknown patient subgroups and examined the heterogeneity in response to SGRQ Symptoms scores. Results: SGRQ Total score improved by 4.24 points with arformoterol and 2.02 points with placebo (P=0.006). Significantly greater improvements occurred for arformoterol versus placebo in SGRQ Symptoms (6.34 vs 4.25, P=0.031) and Impacts (3.91 vs 0.97, P=0.001) scores, but not in Activity score (3.57 vs 1.75, P=0.057). GMM identified responders and nonresponders based on the SGRQ Symptoms score. End-of-study mean difference in SGRQ Symptoms scores between these latent classes was 20.7 points (P<0.001; 95% confidence interval: 17.6-23.9). Compared with nonresponders, responders were more likely current smokers (55.52% vs 44.02%, P=0.0021) and had more severe COPD (forced expiratory volume in 1 second [FEV1]: 1.16 vs 1.23 L, P=0.0419), more exacerbations (0.96 vs 0.69, P=0.0018), and worse mean SGRQ Total (59.81 vs 40.57, P<0.0001), Clinical COPD Questionnaire (3.29 vs 2.05, P<0.0001), and Modified Medical Research Council Dyspnea Scale (3.13 vs 2.75, P<0.0001) scores. Arformoterol-receiving responders exhibited significantly greater improvements in FEV1 (0.09 vs 0.008, P=0.03) and fewer hospitalizations (0.13 vs 0.24, P=0.02) than those receiving placebo. Conclusion: In this study, arformoterol treatment significantly improved HRQoL reflected by SGRQ. For the analysis performed on these data, arformoterol may be particularly effective in improving lung function and reducing hospitalizations among patients who are unable to quit smoking or present with more severe symptoms.

Quantifying the importance of inhaler attributes corresponding to items in the patient satisfaction and preference questionnaire in patients using Combivent Respimat.

BACKGROUND: Physicians consider ease of use, satisfaction, and preferences when prescribing an inhaler device. These factors may impact appropriate usage and compliance. METHODS: The objectives were to quantify the relative importance of inhaler attributes in patients currently using Combivent Respimat by eliciting preferences for performance and convenience attributes assessed by items in the Patient Satisfaction and Preference Questionnaire (PASAPQ). Using a pharmacy database, 19,964 adults in the United States who filled ≥2 Combivent Respimat prescriptions were identified. Of those, 8150 patients were randomly selected to receive invitation letters. The online cross-sectional survey included the PASAPQ and best-worst scaling (BWS) questions. The PASAPQ measures satisfaction with medication attributes across two domains: performance and convenience. BWS questions asked participants to select the most and least important device attributes. A descriptive statistics analysis of the PASAPQ and a random-parameters logit model of BWS responses were conducted. RESULTS: The survey was completed by 503 participants. Most were female (57.3%), white (88.5%), and 51-70 years old (67.6%). Approximately 47% reported a chronic obstructive pulmonary disease diagnosis, 21.9% asthma, 8.2% other lung disease, and 23.1% more than one lung disease. PASAPQ scores indicated that the majority were satisfied or very satisfied; up to 20% reported being dissatisfied with Combivent Respimat. The three most important inhaler attributes were Feeling that your medicine gets into your lungs, Inhaler works reliably, and Inhaler makes inhaling your medicine easy. The most important attributes corresponded to six of seven items in the PASAPQ performance domain. CONCLUSIONS: Most participants reported satisfaction with Combivent Respimat. Performance attributes were more important than convenience attributes.

Health Status of Patients with Moderate to Severe COPD after Treatment with Nebulized Arformoterol Tartrate or Placebo for 1 Year.

PURPOSE: Chronic obstructive pulmonary disease (COPD) is a progressive disease that impairs both objectively measured lung function and patient-reported health status. In a randomized clinical trial of patients with moderate to severe COPD, we compared changes in health status after adding arformoterol tartrate or placebo to patients' treatment regimens. METHODS: In this multicenter, double-blind trial, patients were randomized to receive nebulized arformoterol 15 µg BID (n = 420) or matched placebo (n = 421). Treatment with other COPD medications was permitted, except for long-acting ß2-agonists. Inclusion criteria were a forced expiratory volume in 1 second (FEV1) ≤65% of predicted, FEV1 >0.50 L, age ≥40 years, smoking history ≥15 pack-years, and a baseline breathlessness severity grade ≥2. The Clinical COPD Questionnaire (CCQ) was used to measure health status at randomization and at months 3, 6, and 12. CCQ scores range from 0 to 6, with higher scores indicating worse health status, and a decrease from baseline in total score by 0.4 point is considered clinically significant. Outcomes were analyzed by using mixed models for repeated measures. FINDINGS: At baseline, patients' mean age was 63.8 years; 42.9% of patients were female, and 51.4% were current smokers. The mean baseline CCQ total scores were 2.88 and 2.91 for the arformoterol and placebo groups, respectively. A total of 841 patients were randomized to receive either arformoterol (n = 420) or placebo (n = 421); among them, 211 (50.1%) who received placebo and 255 (60.7%) who received arformoterol completed the trial. Arformoterol-treated patients had greater mean improvement from baseline in CCQ total score (-0.18 vs 0.02; P = 0.001), symptoms (-0.21 vs 0.01; P = 0.002), functional state (-0.15 vs 0.02; P = 0.018), and mental state (-0.18 vs 0.02; P = 0.023) than patients receiving placebo. At study end, 38.3% of the arformoterol-treated patients and 30.8% of patients receiving placebo reported clinically significant improvements on the CCQ (P = 0.026). These improvements were only modestly correlated with improvements in FEV1 (r = -0.15; P < 0.01). IMPLICATIONS: In this 52-week trial, arformoterol-treated patients had greater improvements in health status than patients receiving placebo. Assessing health status along with lung function seems to provide additional information regarding the effectiveness of COPD maintenance treatments. ClinicalTrials.gov identifier: NCT00909779.

Psychometric validation of the Psoriasis Symptom Diary using Phase III study data from patients with chronic plaque psoriasis.

OBJECTIVES: This analysis aimed to confirm the reliability, validity, and responsiveness of the Psoriasis Symptom Diary (PSD) using data from two Phase III studies in patients with moderate to severe chronic plaque psoriasis. METHODS: Data from two randomized, double-blind, double-dummy, placebo-controlled, multicenter Phase III studies (n = 820) assessing the efficacy and safety of secukinumab were used. The PSD (24-h recall; 0-10 numeric rating scale) was electronically administered each evening. Test-retest reliability was determined using intraclass correlations. Construct validity hypotheses were evaluated via correlations with the Psoriasis Area and Severity Index (PASI), Investigator's Global Assessment (IGA), Dermatology Life Quality Index (DLQI), EuroQoL 5-Dimension Health Status Questionnaire, and Patient Global Impression of Change (PGIC). Discriminating ability and responsiveness were evaluated by estimating mean differences and effect sizes between known groups (using the PASI and IGA). Phase II-derived, anchor-based PGIC thresholds and cumulative distribution function (CDF) plots described meaningful change. RESULTS: Items on the PSD yielded high intraclass coefficients (>0.90). Correlations were in the anticipated direction and by week 12 were moderate to strong (0.41-0.73) in magnitude, demonstrating construct validity. Average PSD item scores differed predictably and significantly between known groups. Responsiveness effect size estimates were moderate to large (0.6-1.5), and CDF plots showed the percentage of responders to be consistently higher in treatment than in placebo arms across the range of change in PSD scores. CONCLUSIONS: The PSD is reliable, valid, and responsive, and represents a valid tool to enhance treatment decisions in patients with moderate to severe plaque psoriasis.

Comparison of adequate relief with symptom, global, and responder endpoints in linaclotide phase 3 trials in IBS-C.

BACKGROUND: Optimal clinical trial endpoints for irritable bowel syndrome with constipation (IBS-C) are uncertain. OBJECTIVE: The objective of this article is to compare adequate relief (AR) to abdominal/bowel symptoms, global endpoints, and FDA and EMA responder criteria; and to use AR as an anchor to assess clinically meaningful change (CMC) in IBS-C symptoms. METHODS: Using pooled 12-week data from two phase 3 linaclotide clinical trials, daily abdominal/bowel symptoms and weekly global assessments were correlated with AR. Symptom CMC thresholds were estimated using AR as an anchor. Agreement between AR and FDA/EMA responder criteria was assessed. RESULTS: Correlations of AR with percentage change in abdominal symptoms, bowel symptoms, and global endpoints ranged from 0.48-0.54, 0.32-0.39, and 0.61-0.71, respectively. Using AR as an anchor, CMC thresholds were 29% improvement in abdominal pain, 29% improvement in abdominal discomfort, and 0.7/week increase in CSBMs, similar to thresholds for IBS-C responder endpoints recommended by the FDA and EMA. There was considerable agreement of weekly responder rates between AR and the FDA and EMA endpoints (on average, 70%-76% and 71%-82% of weeks with agreement, respectively). CONCLUSIONS: AR bridges IBS-C clinical trials, putting into perspective the disparate primary endpoints recommended by professional societies and regulatory authorities, and allowing researchers, practitioners, and regulators to compare trial results.

Psychometric validation of patient-reported outcome measures assessing chronic constipation.

BACKGROUND: Measures assessing treatment outcomes in previous CC clinical trials have not met the requirements described in the US Food and Drug Administration's guidance on patient-reported outcomes. AIM: Psychometric analyses using data from one Phase IIb study and two Phase III trials of linaclotide for the treatment of chronic constipation (CC) were conducted to document the measurement properties of patient-reported CC Symptom Severity Measures. STUDY METHODS: Each study had a multicenter, randomized, double-blind, placebo-controlled, parallel-group design, comparing placebo to four doses of oral linaclotide taken once daily for 4 weeks in the Phase IIb dose-ranging study (n=307) and to two doses of linaclotide taken once daily for 12 weeks in the Phase III trials (n=1,272). The CC Symptom Severity Measures addressing bowel function (Bowel Movement Frequency, Stool Consistency, Straining) and abdominal symptoms (Bloating, Abdominal Discomfort, Abdominal Pain) were administered daily using interactive voice-response system technology. Intraclass correlations, Pearson correlations, factor analyses, F-tests, and effect sizes were computed. RESULTS: The CC Symptom Severity Measures demonstrated satisfactory test-retest reliability and construct validity. Factor analyses indicated one factor for abdominal symptoms and another for bowel symptoms. Known-groups F-tests substantiated the discriminating ability of the CC Symptom Severity Measures. Responsiveness statistics were moderate to strong, indicating that these measures are capable of detecting change. CONCLUSION: In large studies of CC patients, linaclotide significantly improved abdominal and bowel symptoms. These psychometric analyses support the reliability, validity, discriminating ability, and responsiveness of the CC Symptom Severity Measures for evaluating treatment outcomes in the linaclotide clinical studies.

Quantitative challenges facing patient-centered outcomes research.

Patient-centered outcomes research collects and analyzes data from patients and other stakeholders to improve health care delivery and outcomes and guide health care decisions. However, there are a number of challenges in conducting quantitative analyses of patient-centered data. This article provides an overview of the analytical challenges and describes approaches to consider to overcome the challenges, as well as directions for future development.

Treatment effectiveness of pasireotide on health-related quality of life in patients with Cushing's disease.

OBJECTIVE: Cushing's disease (CD) can significantly impair patients' health-related quality of life (HRQOL). This study investigated the treatment effectiveness of pasireotide on HRQOL of CD patients, and assessed the relationships between HRQOL and urinary free cortisol (UFC) and CD-related signs and symptoms. DESIGN: In this phase III, randomized, double-blind study, patients with UFC ≥1.5×upper limit of normal (ULN) received s.c. pasireotide 600 or 900 µg twice daily. The trial primary endpoint was UFC at or below ULN at month 6 without dose titration. Open-label treatment continued through month 12. HRQOL was measured using the Cushing's Quality of Life Questionnaire (CushingQoL) instrument at baseline and follow-up visits until month 12 during which clinical signs and features of CD, and the Beck Depression Inventory II (BDI-II), were also collected. METHODS: Pearson's/Spearman's correlations between changes in CushingQoL and changes in clinical signs and symptoms were assessed. Changes in CushingQoL and the proportion of patients achieving a clinically meaningful improvement in CushingQoL were also compared among patients stratified by mean UFC (mUFC) control status (controlled, partially controlled, and uncontrolled) at month 6. Analyses were also conducted at month 12, with multivariable adjustment for baseline characteristics and CushingQoL. RESULTS: Change in CushingQoL was significantly correlated with changes in mUFC (r=-0.40), BMI (r=-0.39), weight (r=-0.41), and BDI-II (r=-0.54) at month 12 but not at month 6. The percentage of CushingQoL responders at month 12 based on month 6 mUFC control status were as follows: 63, 58.8, and 37.9% in the controlled, partially controlled, and uncontrolled groups respectively. Adjusted CushingQoL scores at month 12 were 58.3 for controlled patients (Δ=11.5 vs uncontrolled, P=0.012) and 54.5 for partially controlled patients (Δ=7.7 vs uncontrolled, P=0.170). CONCLUSIONS: Pasireotide treatment can result in a meaningful HRQOL improvement among those who complete a 12-month treatment period, most often among patients achieving biochemical control.

Psychometric evaluation of the Cushing's Quality-of-Life questionnaire.

BACKGROUND: Cushing's disease (CD) is a rare disorder of chronic hypercortisolism due to an adrenocorticotropic hormone (ACTH)-secreting pituitary corticotroph adenoma. Because hypercortisolism symptoms are wide ranging, it is important to assess a variety of outcomes including both clinical factors, such as cortisol levels, and health-related quality of life (HR-QOL), to better understand the severity and impact of CD on patients and the potential efficacy of CD treatment. Pasireotide, a somatostatin analog that targets somatostatin receptors on the pituitary adenoma, is under development as a treatment for CD. A phase III clinical trial was conducted to investigate its safety and efficacy in patients with CD. In this trial, HR-QOL was assessed with the Cushing's Quality-of-Life (CushingQOL) questionnaire, specifically developed and validated in patients with Cushing's syndrome. OBJECTIVE: Reliability, validity, the ability to detect change, and a minimal important difference (MID) were evaluated for the CushingQOL questionnaire using data from patients diagnosed with CD who participated in the phase III clinical trial designed to assess the safety and efficacy of different doses of pasireotide. METHODS: Adult patients (n = 162) with CD participated in a randomized, double-blind, multinational, phase III clinical trial. Patients received subcutaneous pasireotide (600 µg or 900 µg) twice daily for 3 months (double blind). After 3 months, some patients were unblinded based on their mean urinary free cortisol (mUFC) levels and were given the chance to increase their dosage, while the other patients remained blinded. At month 6, an open-label 6-month period began. The CushingQOL questionnaire was self-administered four times (baseline [n = 160], and at months 3 [n = 134], 6 [n = 113], and 12 [n = 76]). A confirmatory factor analysis (CFA) was conducted. Reliability estimates were calculated for internal consistency (coefficient alpha) and test retest (intraclass correlation coefficients [ICCs]) for patients with stable hypercortisolism at month 3 and month 6. Construct validity hypotheses (correlations), mean differences in known groups (ANOVAs), and responsiveness effect sizes (Guyatt's) were estimated based on measures of cortisol, body mass index (BMI), waist circumference, weight, facial rubor (redness), striae (stretch marks), bruising, supraclavicular fat pad, dorsal fat pad, and results of the Beck Depression Inventory II (BDI-II). The half-standard deviation distribution method was used to estimate MID. RESULTS: CFA loadings supported a one-factor solution for the CushingQOL questionnaire items. Internal consistency reliability (0.87-0.88) and ICCs (0.87) were high. Construct validity hypotheses were in the anticipated direction. Changes in CushingQOL scores were moderately correlated with changes in mUFC levels, in BMI, and in weight. Mean scores for minimally depressed patients were significantly higher (indicating better HR-QOL) than for severely depressed patients. Moderate Guyatt's responsiveness effect sizes were observed for patients who achieved reductions in weight, BMI, and waist circumference. Using the half-standard deviation method, an estimate of the MID was computed as 10.1. CONCLUSIONS: This study provided evidence within the context of a longitudinal design that the CushingQOL questionnaire is a reliable, valid, and responsive instrument for the assessment of HR-QOL in adults with CD in accordance with recommendations set forth by regulatory agencies in the USA and Europe.

Development and psychometric evaluation of a new patient-reported outcome instrument measuring the functional impact of insomnia.

PURPOSE: The objective of this study was to develop and validate a patient-reported outcome instrument to comprehensively assess the consequences of inadequate sleep for use in insomnia-related studies. METHODS: To inform item development, relevant constructs were identified through patient focus groups, literature review, and expert input. Following a translatability assessment for United States (US) English, US Spanish, and French, the draft items were refined through iterative sets of patient interviews in the United States and France. Psychometric properties were evaluated using patient responses from a validation study including 432 participants with either a diagnosis of primary insomnia or no history of insomnia. RESULTS: Psychometric analyses supported item reduction from 38 to 26 items, yielding a unidimensional scale and preserving the original content (mood, tiredness/energy, memory/concentration, motivation, daily performance, social interaction, sexual functioning). Evidence of internal consistency (coefficient α = 0.97), convergent validity, and known-groups validity also was documented. CONCLUSIONS: The Sleep Functional Impact Scale (SFIS) is a psychometrically sound measure targeting the impact of insomnia on patient functioning. When administered with a sleep diary, this instrument has the ability to provide a more comprehensive assessment of treatment response in clinical studies.

Effects of insulin initiation on patient-reported outcomes in patients with type 2 diabetes: results from the durable trial.

AIM: To examine changes in patient-reported outcome (PRO) measures in patients with type 2 diabetes (T2DM) on oral agents who initiated insulin (insulin lispro mix 25/75 [LM25] or insulin glargine) in the DURABLE trial (n=580). METHODS: Subjects completed generic and diabetes-specific health-related quality-of-life measures (RAND-36 and Diabetes-39) and a symptom assessment measure (DSC-Revised) at baseline and 6 months post insulin initiation. Mean score change was evaluated. Effect size (ES; Cohen's d) and analysis of covariance were used to examine extent and significance of change both within and between treatment groups. RESULTS: Subject characteristics were mean age 57 years, males 59%, duration of diabetes 9.6 years, and baseline HbA1c 8.9%. In the total sample, significant (P<0.01) improvements (with small ES) were observed in four of eight RAND-36 subscales (ES range: 0.13-0.24), three of five Diabetes-39 subscales (ES range: 0.09-0.34), and five of eight DSC-Revised subscales (ES range: 0.15-0.38). While significance of within-group changes varied by treatment, only one subscale (physical functioning for LM25) showed deterioration. The changes were not significantly different (P>0.01) between regimens for any subscales. CONCLUSIONS: Our findings suggest that insulin initiation improves selective PRO in patients with poorly controlled T2DM.

Differential regulation of immature articular cartilage compressive moduli and Poisson's ratios by in vitro stimulation with IGF-1 and TGF-beta1.

Mechanisms of articular cartilage growth and maturation have been elucidated by studying composition-function dynamics during in vivo development and in vitro culture with stimuli such as insulin-like growth factor-1 (IGF-1) and transforming growth factor-beta 1 (TGF-beta1). This study tested the hypothesis that IGF-1 and TGF-beta1 regulate immature cartilage compressive moduli and Poisson's ratios in a manner consistent with known effects on tensile properties. Bovine calf articular cartilage from superficial-articular (S) and middle-growth (M) regions were analyzed fresh or following culture in medium with IGF-1 or TGF-beta1. Mechanical properties in confined (CC) and unconfined (UCC) compression, cartilage matrix composition, and explant size were assessed. Culture with IGF-1 resulted in softening in CC and UCC, increased Poisson's ratios, substantially increased tissue volume, and accumulation of glycosaminoglycan (GAG) and collagen (COL). Culture with TGF-beta1 promoted maturational changes in the S layer, including stiffening in CC and UCC and increased concentrations of GAG, COL, and pyridinoline crosslinks (PYR), but little growth. Culture of M layer explants with TGF-beta1 was nearly homeostatic. Across treatment groups, compressive moduli in CC and UCC were positively related to GAG, COL, and PYR concentrations, while Poisson's ratios were negatively related to concentrations of these matrix components. Thus, IGF-1 and TGF-beta1 differentially regulate the compressive mechanical properties and size of immature articular cartilage in vitro. Prescribing tissue growth, maturation, or homeostasis by controlling the in vitro biochemical environment with such growth factors may have applications in cartilage repair and tissue engineering.