Measuring respiratory symptoms in clinical trials of COPD: reliability and validity of a daily diary.

BACKGROUND: Although respiratory symptoms are characteristic features of COPD, there is no standardised method for quantifying their severity in stable disease. OBJECTIVE: To evaluate the EXACT-Respiratory Symptom (E-RS) measure, a daily diary comprising 11 of the 14 items in the Exacerbations of Chronic Pulmonary Disease Tool (EXACT). METHODS: Qualitative: patient focus group and interviews to address content validity. Quantitative: secondary data analyses to test reliability and validity. RESULTS: Qualitative: n=84; mean (SD) age 65 (10) years, FEV1 1.2(0.4) L; 44% male. Subject descriptions of their respiratory symptoms were consistent with E-RS content and structure. Quantitative: n=188; mean (SD) age 66 (10) years, FEV1 1.2(0.5) L; 50% male. Factor analysis (FA) showed 3 subscales: RS-Breathlessness, RS-Cough & Sputum, and RS-Chest Symptoms; second-order FA supported a general factor and total score. Reliability (total and subscales): 0.88, 0.86, 0.73, 0.81; 2-day test-retest ICC: 0.90, 0.86, 0.87, 0.82, respectively. VALIDITY: Total scores correlated significantly (p < 0.0001) with SGRQ Total (r=0.75), Symptoms (r=0.66), Activity (r=0.57), Impact (r=0.70) scores; subscale correlations were also significant (r=0.26, p < 0.05 (RS-Chest Symptoms with Activity) to r=0.69, p < 0.0001 (RS-Cough & Sputum with Symptoms). RS-Breathlessness correlated with rescue medication use (r=0.32, p < 0.0001), clinician-reported mMRC (r=0.33, p < 0.0001), and FEV1% predicted (r=-0.17, p < 0.05). E-RS scores differentiated groups based on chronic bronchitis diagnosis (p < 0.01-0.001), smoking status (p < 0.05-0.001), and rescue medication use (p < 0.05-0.0001). CONCLUSIONS: Results suggest the RS-Total is a reliable and valid instrument for evaluating respiratory symptom severity in stable COPD. Further study of sensitivity to change is warranted.

Assessing the impact of dabigatran and warfarin on health-related quality of life: results from an RE-LY sub-study.

BACKGROUND: Anticoagulation is recommended in patients with atrial fibrillation (AF) to prevent strokes. Vitamin K antagonists, such as warfarin, are associated with numerous practical limitations--frequent anticoagulation monitoring, lifestyle and dietary restrictions--that complicate patient management and may impact health-related quality of life (HRQoL). This study derived HRQoL estimates for AF patients receiving warfarin or dabigatran etexilate (dabigatran), a new oral anticoagulant not requiring anticoagulation monitoring, during one year of stable treatment, i.e. in the absence of outcome events, such as strokes or major bleedings. METHODS: Changes in HRQoL over time and between treatments were assessed using the EQ-5D (utility and Visual Analogue Scale (VAS) scores) at baseline, 3 and 12 months in a sub-group of 1435 patients participating in the RE-LY trial. RE-LY was a phase III study that compared the safety and efficacy of warfarin, dabigatran 150 mg bid and dabigatran 110 mg bid for stroke prevention in patients with AF. RESULTS: Utilities ranged from 0.805 (dabigatran 150 mg bid) to 0.811 (dabigatran 110 mg bid) at baseline, and did not change over the one year observation period. No differences between the dabigatran groups and warfarin were statistically significant except for the dabigatran 150 mg bid group at 3 months. Similarly, none of the within-group or between-group differences in VAS scores were statistically significant. CONCLUSIONS: Over the course of one year, all anticoagulated patients without outcome events (e.g. strokes or major bleedings) had stable HRQoL. Scores between dabigatran and warfarin were comparable, which was unexpected given the known complexities of warfarin treatment.

Preferences for medication attributes among patients with type 2 diabetes mellitus in the UK.

AIM: To examine preferences for oral medication attributes among participants with early and advanced type 2 diabetes mellitus (T2DM) in the UK using a discrete choice experiment (DCE). METHODS: A web-based DCE was administered where participants indicated which medication they preferred from two different hypothetical oral anti-diabetic (OAD) medication profiles, each composed of differing levels of seven attributes (efficacy, hypoglycaemic events, weight change, gastrointestinal/nausea side effects, urinary tract infection and genital infection, blood pressure and cardiovascular risk) for 20 sets of pair-wise comparisons. A random effects multinomial logit regression model was used to estimate the preference weight (PW) for each of the attribute levels, and the relative importance (RI) of each attribute was calculated. Analyses were conducted for the overall sample and for medication and gender subgroups. RESULTS: The final sample included 100 participants with a mean age of 62.9 (SD 11.1) years and comparable numbers of participants of each gender (51% male, 49% female). The majority of the participants were White-British (92%). The total PW and corresponding RI were highest for four of the seven attributes: hypoglycaemic events (PW = 1.98; RI = 24.7%), weight change (PW = 1.65; RI = 20.6%), gastrointestinal/nausea side effects (PW = 1.49; RI = 18.6%) and efficacy (PW = 1.44; RI = 18.0%). The RI values differed for some attributes across gender and number of current T2DM medication subgroups. CONCLUSION: The results suggest that hypoglycaemia, weight change, gastrointestinal side effects and efficacy are of primary importance to patients in their OAD preferences in T2DM. These four attributes comprised over 80% of the RI.

The patient-reported outcome (PRO) consortium: filling measurement gaps for PRO end points to support labeling claims.

The importance of appropriately and effectively incorporating the patient's voice into the evaluation of new medical products has been recognized and affirmed by regulators.(1,2,3) Patient-reported outcomes (PROs) are increasingly being assessed in clinical trials to quantify treatment benefits such as symptom relief and improved functioning. Translating PRO-based treatment benefits into labeling claims can provide information to physicians and patients and assist in prescribing decisions.(4,5) Hence, standardizing the valid and reliable measurement of PRO end points is critical.

Presence and predictors of pain in depression: results from the FINDER study.

BACKGROUND: Patients with depression often experience pain. There is limited understanding of the relation between pain and other symptoms (depressive, anxious and non-painful somatic symptoms). This exploratory study assesses pain severity and interference of pain with functioning in a clinically depressed population and investigates the relation between the different groups of symptoms. METHODS: FINDER was a 6-month prospective, observational study investigating health-related quality of life of outpatients with depression initiating antidepressant treatment. Patients completed ratings on the Hospital Anxiety and Depression Scale (HADS), Somatic Symptom Inventory (SSI-28), and overall pain severity and interference of pain with functioning using Visual Analogue Scales (VAS) at baseline and at 3 and 6 months. Regression analyses identified factors associated with overall pain severity and interference of pain with functioning, at baseline and over the observation period. RESULTS: Of 3468 eligible patients at baseline, 56.3% experienced moderate to severe pain and 53.6% had moderate to severe pain-related interference with functioning. At 6 months of follow-up, these proportions decreased to 32.5% and 28.1%, respectively. Higher baseline SSI-somatic scores (non-painful) were strongly associated with greater pain severity and greater pain-related interference with functioning at baseline and over 6 months. Certain socio-demographic (increasing age, being unemployed) and depression-related factors (more previous episodes, longer duration of current episode) were also significantly associated with greater pain severity and interference over 6 months, while higher baseline severity of depression (HADS-D) and further education were associated with less severe pain or pain-related interference with functioning over 6 months. CONCLUSIONS: Over half of depressed patients in this study experienced moderate to severe pain. Painful somatic symptoms appear to be closely related to non-painful somatic symptoms, more than to depressive or anxious symptoms suggesting that painful and non-painful somatic symptoms can be considered as one group of 'somatic symptoms,' all of them associated with depressive and anxious symptoms.

Cost-effectiveness of venous thromboembolism prophylaxis in total hip and knee replacement surgery: the evolving application of health economic modelling over 20 years.

OBJECTIVES: In the last two decades, there has been considerable evolution of methods for cost-effectiveness modelling. Some of the first models were developed in the area of venous thromboembolism (VTE) prophylaxis. Hence, this area can serve as an important example to illustrate evolving standards. Our objectives are to document evolving methodology by describing VTE models, assess their critical strengths and weaknesses, and inform future advances for models in this therapeutic area. RESEARCH DESIGN AND METHODS: A systematic review of economic models of primary VTE prevention following hip and knee replacement surgery was undertaken. Electronic searches of PubMed, EMBASE, the Cochrane library, and grey literature were conducted (1985-2006). Reference lists of included articles and reviews were examined for relevant studies. RESULTS: Twenty-nine cost-effectiveness models were identified. Nineteen other cost-effectiveness analyses were excluded because they were not model-based; 16 were simple cost calculations and three were analyses of resource use data collected alongside clinical trials. The majority of models (24) were constructed as decision trees, frequently utilising previously published model structures, with some adaptation for new comparators, and/or addition of relevant events omitted by earlier models (e.g., bleeding due to prophylactic treatment). Later models have included Markov processes to model potential long-term consequences of VTE (recurrent VTE and post-thrombotic syndrome) over longer time horizons. Systematic identification of clinical evidence and more sophisticated analysis methods (e.g., Bayesian mixed-treatment comparisons and probabilistic sensitivity analyses) have recently been introduced. CONCLUSIONS: Model structures have evolved substantially in this highly studied therapeutic area, with improvements made to the model structure, the comprehensiveness of clinical evidence included, and the underlying calculation methodology.

Cost effectiveness of duloxetine in the treatment of diabetic peripheral neuropathic pain in the UK.

OBJECTIVE: The objective of this analysis was to evaluate the cost-effectiveness of duloxetine when considered as an additional treatment option for UK-based patients suffering from diabetic peripheral neuropathic pain. RESEARCH DESIGN AND METHODS: A decision-analytic model was used to represent the sequential management of patients with diabetic peripheral neuropathic pain. The standard UK treatment strategy was defined as first-line tricyclic antidepressants (amitriptyline), second-line anticonvulsants (gabapentin) and lastly an opioid-related treatment. The cost-effectiveness of duloxetine was evaluated as an additional first, second, third or fourth-line therapy over a 6-month treatment period for a cohort of 1000 patients. Treatment response was modelled based on changes from baseline pain severity using a standard 11-point pain scale (0-10); full response (>or= 50% change), partial response (30-49%) and no response (< 30%). The model was populated with efficacy and discontinuation data using indirect comparisons of treatment efficacy based on relative effects to a common placebo comparator. RESULTS: The second-line use of duloxetine resulted in cost savings of pound 77,071 for every 1000 treated patients, with an additional 29 patients achieving a full pain response when compared to standard UK treatment. Additional quality-adjusted life years (QALYs) were achieved at 1.88 QALYs per 1000 patients. CONCLUSIONS: This UK-based economic model suggests that second-line use of duloxetine is a beneficial and cost-effective treatment strategy for diabetic peripheral neuropathic pain.

Estimated prevalence of peripheral neuropathy and associated pain in adults with diabetes in France.

OBJECTIVE: To estimate the point prevalence of diabetic peripheral neuropathy (DPN) and pain associated with DPN (pDPN) in French adults with diabetes and compare severity of symptoms across demographic subpopulations. DESIGN: The participant-administered portion of the Michigan Neuropathy Screening Instrument (MNSI) and selected items of the Brief Pain Inventory (BPI) formed part of a computer-aided telephone survey posed to a representative, random sample of French households from March 1, 2005 to April 30, 2005. Questions from the MNSI and the BPI were used to assess the point prevalence of DPN and pDPN in French adults with self-reported diabetes. RESULTS: The mean age of the study sample was 68 years (SD = 15), the mean duration of diabetes was 15 years (SD = 12) and 56% of participants were female. The prevalence rates of DPN and pDPN in French adults with diabetes were 11 and 8%, respectively. The average age and diabetes duration of participants with DPN and pDPN were not different from participants in the total sample. Among those participants with pDPN, 35% classified their pain as severe, 49% as moderate, and 17% as mild. The prevalence of DPN was higher in participants with type 1 diabetes (14%) than those with type 2 (9%). Among participants with DPN, 88% with severe pain received pain treatment compared to 71% with moderate pain and 58% with mild pain. The most significant limitation of this study is the lack of validation for administering only a portion of the MNSI, but other limitations include the imprecision associated with self-reported questionnaires, a survey sample that does not include participants with undiagnosed diabetes, and a bias toward elderly participants. CONCLUSION: This study concluded that 8% of participants with diabetes in France had pDPN.

Proliferation and oxygenation status of widr spheroids in different lactate and oxygen environments.

Human colon adenocarcinoma cells WiDr were cultured as monolayers or multicellular spheroids in 5% or 20% (v/v) oxygen and in various external lactate concentrations of 0-20 mM. Doubling times and H-3-thymidine labeling indices of exponential monolayer cells indicated that there was no difference in growth behavior between the two oxygen environments, yet these parameters reflected a growth retardation upon elevation of lactate. Growth of WiDr spheroids was retarded in both low oxygen and high lactate concentrations. There was a tendency towards a decrease in the thickness of the viable cell rim with increasing lactate in 20% O-2, whereas the width of the viable rim increased significantly as a function of external lactate in 5% O-2. Intraspheroidal oxygen tensions (Po-2) measured with microelectrodes were less in 5% O-2 than in 20% O-2, yet did not vary systematically as a function of external lactate. Po-2 values in the spheroid center dropped to 0 mm Hg prior to the emergence of central necrosis under all conditions investigated. Unlike numerous other spheroid types investigated up to now, WiDr spheroids mimic tumor microregions with hypoxia-induced necrosis and with nonproliferating cells at very low oxygen pressure.