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.

Evaluating the Power of Food Scale in obese subjects and a general sample of individuals: development and measurement properties.

BACKGROUND: The Power of Food Scale (PFS) was developed to assess the psychological impact of today's food-abundant environments. OBJECTIVE: To evaluate the structure of the PFS in diverse populations of obese and nonobese individuals. DESIGN: Data were obtained from obese adults in a clinical trial for a weight management drug (n=1741), and overweight, obese and normal weight adults in a Web-based survey (n=1275). Exploratory and confirmatory factor analyses were used to investigate the PFS structure using the clinical data. The model developed was then tested using the Web-based data. Relationships between PFS domains and body mass index (BMI) were examined. Logistic regression was used in the Web-based survey to evaluate the association between obesity status and PFS scores. RESULTS: Clinical data indicated that the scale was best represented by a 15-item version with three subscale domains and an aggregate domain (average of three domains); this was confirmed with data from the Web-based survey (Comparative Fit Index: 0.95 and 0.94 for the clinical and Web-based studies, respectively). Cronbach's alpha for both data sets was high, ranging from 0.81 to 0.91. The relationships between BMI and each domain were weak (and approximately linear). A full category increase in PFS domain score (range 1-5) increased the odds of being obese 1.6-2.3 times. CONCLUSIONS: The 15-item PFS is best represented by three domains and an aggregate domain. The PFS may provide a useful tool to evaluate the effects of obesity treatments on feelings of being controlled by food in an obesogenic food environment.

Psychometric analysis of the Three-Factor Eating Questionnaire-R21: results from a large diverse sample of obese and non-obese participants.

BACKGROUND: The 21-item Three-Factor Eating Questionnaire (TFEQ-R21) is a scale that measures three domains of eating behavior: cognitive restraint (CR), uncontrolled eating (UE) and emotional eating (EE). OBJECTIVES: To assess the factor structure and reliability of TFEQ-R21 (and if necessary, refine the structure) in diverse populations of obese and non-obese individuals. DESIGN: Data were obtained from obese adults in a United States/Canadian clinical trial (n=1741), and overweight, obese and normal weight adults in a US web-based survey (n=1275). Confirmatory factor analyses were employed to investigate the structure of TFEQ-R21 using baseline data from the clinical trial. The model was refined to obtain adequate fit and internal consistency. The refined model was then tested using the web-based data. Relationships between TFEQ domains and body mass index (BMI) were examined in both populations. RESULTS: Clinical data indicated that TFEQ-R21 needed refinement. Three items were removed from the CR domain, producing the revised version TFEQ-R18V2 (Comparative Fit Index (CFI)=0.91). Testing TFEQ-R18V2 in the web-based sample supported the revised structure (CFI=0.96; Cronbach's coefficient alpha of 0.78-0.94). Associations with BMI were small. In the clinical study, the CR domain showed a significant and negative association with BMI. On the basis of the web-based survey, it was shown that the relationship between BMI and CR is population-dependent (obese versus non-obese, healthy versus diabetics). CONCLUSIONS: In two independent datasets, the TFEQ-R18V2 showed robust factor structure and good reliability. It may provide a useful tool for characterizing UE, CR and EE.

Estimating health utilities in patients with asthma and COPD: evidence on the performance of EQ-5D and SF-6D.

OBJECTIVE: The objective of this study was to understand systematic differences in utility values derived from the EQ-5D and the SF-6D in two respiratory populations with heterogeneous disease severity. METHODS: This study involved secondary analysis of data from two cross-sectional surveys of patients with asthma (N = 228; Hungary) and COPD (N = 176; Sweden). Disease severity was defined according to GINA and GOLD guidelines for asthma and COPD, respectively. EQ-5D and SF-6D scores and their distributional characteristics were compared across the two samples by disease severity level. RESULTS: Within each patient population, mean EQ-5D and SF-6D scores were similar for the overall group and for those with moderate disease. Mean scores varied for patients with mild and severe disease. EQ-5D versus SF-6D scores in the asthma group by severity levels were 0.89 versus 0.80, 0.70 versus 0.73, 0.63 versus 0.64, and 0.51 versus 0.63, respectively. EQ-5D versus SF-6D scores in the COPD group by severity levels were 0.85 versus 0.80, 0.73 versus 0.73, 0.74 versus 0.73, and 0.53 versus 0.62, respectively. CONCLUSIONS: Results suggest the EQ-5D and SF-6D do not yield consistent utility values in patients with asthma and COPD due to differences in underlying valuation techniques and the EQ-5D's limited response options relative to mild disease.

Health-related quality of life in patients receiving reduced-intensity conditioning allogeneic hematopoietic stem cell transplantation.

Reduced-intensity conditioning allogeneic HSCT (RIC) has less regimen-related morbidity and mortality than myeloablative allogeneic HSCT (MT) offering allogeneic transplantation to patients otherwise excluded. Whether these advantages improve health-related quality of life (HRQL) is unknown. We examined the HRQL effects of RIC and MT in patients with hematological diseases pre-transplant (baseline), days 0, 30, 100, 1 and 2 years following HSCT. HRQL was measured using the Short Form-36 Health Survey and the Functional Assessment of Cancer Therapy - General and BMT. Data were analyzed using mixed linear modeling adjusting for baseline HRQL differences. Patients (RIC=41, MT=35) were predominately male (67%), in remission/stable disease (65%) with an Eastern Cooperative Oncology Group status

The health-related quality of life effects of once-daily cetirizine HCl in patients with seasonal allergic rhinitis: a randomized double-blind, placebo-controlled trial.

BACKGROUND: Seasonal allergic rhinitis (SAR) is characterized by subjectively irritating symptoms that can have a substantial impact on the patient's health-related quality of life (HRQL), adversely affecting physical and social or work activity, interpersonal relationships, and general psychological well-being. The objective of this study was to test the effect of cetirizine HCl 10 mg once daily on the HRQL of adult patients 18-65 years of age with SAR, concurrently assessing safety and efficacy. METHODS: Randomized double-blind, placebo-controlled, parallel group trial conducted during the 1999 spring SAR season at 19 centers in the US. Following a 1-week placebo run-in period, qualified patients were randomized to cetirizine 10 mg, or placebo once daily for a 2-week treatment period. Change in Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) and Total Symptom Severity Complex (TSSC) scores from baseline were the primary outcomes of interest. RESULTS: Of the 611 patients enrolled, 403 (66%) were randomized. Cetirizine-treated patients reported significantly greater improvement in overall HRQL (P < 0.001) and in each of the seven domains of the RQLQ at all time-points (P < 0.05 to < 0.001) than the placebo group. They also experienced significantly greater symptom relief (P < 0.001) and were more satisfied with treatment (65% vs. 44%) compared to the placebo group. Correlations between symptomatic relief and overall HRQL improvement were moderate to strong and statistically significant (r = 0.49-0.68, P < 0.01). CONCLUSIONS: Results of this study are consistent with previous investigations, suggesting cetirizine HCl 10 mg taken once daily in the morning offers symptomatic relief that improves the HRQL of adults suffering from SAR.

Evaluating symptoms in chronic obstructive pulmonary disease: validation of the Breathlessness, Cough and Sputum Scale.

This study examined the reliability and validity of a new measure for evaluating symptoms in patients with chronic obstructive pulmonary disease (COPD): the Breathlessness, Cough and Sputum Scale (BCSS). Designed as a daily diary, the BCSS is a patient-reported outcome measure that asks patients to rate the severity of the three symptoms, each on a 5-point scale; higher scores indicate more severe symptoms. Item scores are summed to yield a total score. Secondary analysis of data were from two multinational trials (n = 629; 765). The BCSS item and total scores exhibited evidence of internal consistency (alpha = 0.70 daily; 0.95 to 0.99 over time) and reproducibility (ICC = 0.77 to 0.88). Correlations (r) with pulmonary function (FEV1 % predicted, PEF) were -0.01 (n.s.) to -0.36 (P < 0.001). Correlations with the St George's Respiratory Questionnaire total and SF-36 Physical Functioning subscale were 0.44 to 0.59 (P < 0.0001). Breathlessness and total scores differentiated patients by disease severity (P < 0.01) and rescue medication use (P < 0.01). Cough, sputum, and total scores increased with sputum volume (r = 0.27, 0.30, 0.31; P < 0.001). Patients for whom treatment was moderately or highly effective reported significant improvements in BCSS scores (P < 0.0001). Results suggest that the BCSS is a reliable, valid, and responsive patient-reported outcome measure of symptom severity in patients with COPD.

Comparative effects of candesartan cilexetil and amlodipine in patients with mild systemic hypertension. Comparison of Candesartan and Amlodipine for Safety, Tolerability and Efficacy (CASTLE) Study Investigators.

The comparative antihypertensive efficacy and tolerability of the angiotensin II receptor blocker candesartan cilexetil and the calcium channel blocker amlodipine were evaluated in an 8-week, multicenter, double-blind, randomized, parallel-group, forced-titration study in 251 adult patients (45% women, 16% black) with mild hypertension (stage 1). Following a 4- to 5-week placebo run-in period, patients with sitting diastolic blood pressure (BP) of 90 to 99 mm Hg received candesartan cilexetil 16 mg (n = 123) or amlodipine 5 mg (n = 128) once daily. After 4 weeks of double-blind treatment, patients were uptitrated to candesartan cilexetil 32 mg or amlodipine 10 mg once daily. There were no significant differences between the candesartan cilexetil and amlodipine regimens for reducing BP; mean systolic BP/diastolic BP reductions were -15.2/-10.2 mm Hg versus -15.4/-11.3 mm Hg, respectively (p = 0.88/0.25). Overall, 79% of patients on candesartan cilexetil and 87% of those on amlodipine were controlled (diastolic BP <90 mm Hg). A total of 3.3% of patients on candesartan cilexetil discontinued treatment, compared with 9.4% of patients on amlodipine, including 2.4% versus 4.7% for adverse events and 0% versus 1.6% for peripheral edema, respectively. Peripheral edema, the prespecified primary tolerability end point, occurred with significantly greater frequency in patients on amlodipine (22.1%; mild 8.7%, moderate 11.8%, severe 1.6%) versus patients on candesartan cilexetil (8.9%; mild 8.1%, moderate 0.8%) (p = 0.005). Candesartan cilexetil and amlodipine are both highly effective in controlling BP in patients with mild hypertension. Candesartan cilexetil offers a significant tolerability advantage with respect to less risk of developing peripheral edema.

A comparative trial of paper-and-pencil versus computer administration of the Quality of Life in Reflux and Dyspepsia (QOLRAD) questionnaire.

BACKGROUND: Although most health-related quality of life questionnaires are self-administered by means of paper and pencil, new technologies for automated computer administration are becoming more readily available. Novel methods of instrument administration must be assessed for score equivalence in addition to consistency in reliability and validity. OBJECTIVES: The present study compared the psychometric characteristics (score equivalence and structure, internal consistency, and reproducibility reliability and construct validity) of the Quality of Life in Reflux And Dyspepsia (QOLRAD) questionnaire when self-administered by means of paper and pencil versus touch-screen computer. The influence of age, education, and prior experience with computers on score equivalence was also examined. RESEARCH DESIGN: This crossover trial randomized 134 patients with gastroesophageal reflux disease to 1 of 2 groups: paper-and-pencil questionnaire administration followed by computer administration or computer administration followed by use of paper and pencil. To minimize learning effects and respondent fatigue, administrations were scheduled 3 days apart. A random sample of 32 patients participated in a 1-week reproducibility evaluation of the computer-administered QOLRAD. RESULTS: QOLRAD scores were equivalent across the 2 methods of administration regardless of subject age, education, and prior computer use. Internal consistency levels were very high (alpha = 0.93-0.99). Interscale correlations were strong and generally consistent across methods (r = 0.7-0.87). Correlations between the QOLRAD and Short Form 36 (SF-36) were high, with no significant differences by method. Test-retest reliability of the computer-administered QOLRAD was also very high (ICC = 0.93-0.96). CONCLUSIONS: Results of the present study suggest that the QOLRAD is reliable and valid when self-administered by means of computer touch-screen or paper and pencil.

Patient-based assessment in dyspepsia: development and validation of Dyspepsia Symptom Severity Index (DSSI).

This paper describes the development and testing of a new self-report measure, the Dyspepsia Symptom Severity Index (DSSI), for assessing the severity of symptoms commonly associated with dyspepsia. The instrument was based on the literature, focus groups, and feedback from gastroenterologists; 48 patients and 24 controls participated in testing. Patients completed the DSSI and a symptom diary to test concurrent validity; one-week reproducibility was evaluated in 21 stable patients. Three subscales comprise the 20-item DSSI, representing reflux-, ulcer-, and dysmotility-like symptoms. Subscale internal consistency levels (alpha) were high (0.84-0.89), total score alpha levels were very good (0.76, 0.80), and scores were reproducible (ICC = 0.90-0.92). Correlations between the DSSI and diary were moderate to strong (r = 0.33-0.77; P < 0.05). Patients reported significantly more severe symptoms than controls (P < 0.001). Results indicate the DSSI is a reliable and valid tool for evaluating symptom severity in patients with functional dyspepsia.

Psychometric properties of the VSQLQ in black patients with mild hypertension. Vital Signs Quality of Life Questionnaire.

The Vital Signs Quality of Life Questionnaire (VSQLQ) is a condition- and culture-specific measure designed to assess health-related quality of life (HRQL) in black patients with hypertension. This study examined the instrument's reliability and validity when administered via personal interview to patients with mild systemic hypertension. Data were gathered from 304 black patients during the screening visit of a multicenter trial evaluating the efficacy of candesartan cilexetil (ATACAND). In addition to internal consistency and reproducibility, validity was assessed by correlating the VSQLQ with the Short Form-36 (SF-36). Sensitivity to sociodemographic effects and responsiveness to change was also examined. Cronbach's alpha levels were high (0.90, 0.92, 0.92 for frequency, intensity and combined scores, respectively) and the instrument was stable in patients reporting no health change over 8 weeks (ICC = 0.79, 0.79, and 0.80). Correlations between the VSQLQ and the SF-36 were moderate to high (0.32 to - 0.69) and statistically significant (p < 0.001). VSQLQ scores varied by gender, education, and income (p < 0.05). Patients who reported improvement in their general health status also reported significant improvements on the VSQLQ (n = 90; p < 0.05). Results support the reliability and validity of VSQLQ administered via personal interview to black patients with mild systemic hypertension.

Recommendations on health-related quality of life research to support labeling and promotional claims in the United States.

Health-related quality of life (HRQL) outcomes evaluation is becoming an important component of clinical trials of new pharmaceuticals and medical devices. HRQL research provides patients, providers, and decision makers with important information on the impact of disease and treatment on physical, psychological, and social functioning and well-being. These outcomes are also useful to the pharmaceutical and device industries as they attempt to understand and communicate product value to physicians, patients, health insurers and others. HRQL labeling and promotional claims in the US are likely to increase over the next few years. The evidentiary requirements to make such a claim should be based on accepted scientific standards of HRQL evaluation and consistent with the regulatory requirements for clinical efficacy. This report outlines the scientific practices that should be considered in the evaluation of evidence for an HRQL claim, including the selection of appropriate domains, evidence to support the reliability and validity of HRQL measurement, considerations in research design and statistical analyses, and the issue of clinical significance. Representatives from the pharmaceutical and device industries, regulatory agencies, and the HRQL scientific community should work together to make certain the use of HRQL in labeling and promotion are based on sound scientific evidence, and that these messages are clearly and accurately reported to the consumers.

Effects of candesartan cilexetil on health-related quality of life in black patients with systemic hypertension in the ABC Trial.

Tolerability is an important consideration in evaluating a new antihypertensive agent. This can be assessed informally by conventional patient interviews or more formally with the use of validated health-related quality of life (HRQL) measures assessing the patient's perception of the agent's tolerability. HRQL was a secondary end point of a 12-week, multicenter, double-blind, randomized, placebo-controlled study of the efficacy and tolerability of candesartan cilexetil in black patients with systemic hypertension. HRQL was evaluated using the generic Medical Outcomes Study 36-Item Short Form (SF-36) and population- and condition-specific Vital Signs Quality of Life Questionnaire (VSQLQ). Data were gathered via face-to-face interviews at screening, baseline, and weeks 8 and 12. Of the 304 patients randomized, 268 were evaluable for the HRQL analysis. Clinical results, reported in the companion article, found that candesartan cilexetil initiated at 16 mg once daily and titrated to 32 mg once daily as needed, with the subsequent addition of hydrochlorothiazide 12.5 mg as needed, was effective for lowering diastolic and systolic blood pressure and was well tolerated based on office interviews. Analyses of patients' perceptions of tolerability found that HRQL was maintained during the 12-week study period, with no significant differences between treatment and placebo groups at the end of double-blind treatment. These results indicate that the HRQL of black patients with systemic hypertension is maintained during treatment with candesartan cilexetil.

The relationship between memory performance, perceived cognitive function, and mood in patients with epilepsy.

OBJECTIVE: The low correlations between memory performance and subjective memory may be attributable to disparities between tasks in neuropsychological tests and cognitive experiences of day-to-day living. This study evaluated the relationship between everyday memory performance, perceived cognitive functioning, and mood among patients with epilepsy. METHODS: From three epilepsy centers in the USA, 138 patients were recruited. Everyday memory performance was measured using the Rivermead Behavioural Memory Test (RBMT). Questionnaires assessed perceived cognitive function (cognitive domain, Quality of Life in Epilepsy Inventory, QOLIE-89) and mood (Profile of Mood States, POMS). RESULTS: Memory performance scores were weakly correlated with perceived cognitive functioning (r =0.22, P < 0.01). Perceived cognitive functioning was strongly correlated with mood (r = - 0.75, P < 0.0001). Multiple regression analysis indicated memory performance (RBMT) and mood (POMS) were independent predictors of perceived cognitive functioning (P < 0.02); however, the explained variance for RBMT and POMS combined (R2 = 0.58) is only slightly higher than the predictive value for the POMS score alone (R2 = 0.56). CONCLUSIONS: Memory performance tests provide qualitatively different information than patients' self-reported cognitive difficulties, thus it is important to assess memory performance, perceived cognitive function, and mood separately because the constructs are related but not redundant.

Health related quality of life and disease severity in patients with alpha-1 antitrypsin deficiency.

STUDY QUESTION: To describe health-related quality of life (HRQL) in individuals with alpha-1 antitrypsin (AAT) deficiency, examine the cross-sectional relationship between disease severity and HRQL, and explore changes in lung function and HRQL over time in a subset of these individuals. MATERIAL/METHODS: Forty-five adults with AAT deficiency and moderate to severe emphysema completed the Chronic Respiratory Disease Questionnaire (CRQ), six-minute walk distance (6-MWD) and pulmonary function tests (PFTs). Twenty of the 45 were followed for two additional years with repeated measurements of CRQ and PFTs. RESULTS: The mean +/- SD age was 49 +/- 8 years. Initial CRQ subscale scores were: dyspnea 17.5 +/- 4.3; fatigue 17.0 +/- 5.46; emotional function 33.1 +/- 8.67; and mastery 21.7 +/- 4.65. No relationship was found between percent predicted forced expiratory volume in one second (FEV1%) and CRQ score; 6 MWD and fatigue correlated significantly (r = 0.32, p < 0.05). Repeated PFT and CRQ measurements in 20 subjects showed statistically significant declines in FEV1 and slow vital capacity (SVC), but no change in CRQ scores. CONCLUSIONS: Results suggest persons with AAT deficiency face challenges to HRQL that are similar to older adults with chronic pulmonary disease. Further research is needed on the nature of the relationship between disease severity and HRQL in this population.

Seizure frequency and the health-related quality of life of adults with epilepsy.

OBJECTIVE: To compare the health-related quality of life (HRQL) of a nonsurgical sample of adults with epilepsy with that of age- and gender-equivalent norms, and to analyze the relative importance of seizure frequency, time since last seizure, gender, and comorbidity on HRQL in the epilepsy sample. METHODS: Data were obtained from 139 adults with epilepsy from three US centers and published norms on the Medical Outcomes Study Short-Form 36 (SF-36). Patients were classified according to number of seizures over the prior 4 weeks (zero, one to five, six or more). Bivariate and multivariate modeling was used. RESULTS: HRQL scores for seizure-free patients were similar to the general population. Significant differences between seizure frequency groups were found for seven domains and the physical and mental component summary scales of the SF-36 (p<0.001). No differences were found in bodily pain. The largest differences were in physical role and social functioning, and general health (p<0.001). In the multivariate model, seizure frequency was a significant inverse predictor of HRQL across all domains (p<0.01 to 0.001). Men reported poorer physical function than women (p<0.05), and patients with a comorbid condition had poorer HRQL in the areas of pain (p<0.05) and general health perception (p<0.01). Time since last seizure was not related uniquely to HRQL. CONCLUSIONS: Seizure-free adults can have HRQL levels comparable with those of the general population. As seizure frequency increases, patients report more impaired HRQL, regardless of time since last seizure, gender, and comorbid status. Potential for difficulties in HRQL should be considered in clinical assessment and in evaluating treatment outcomes.

Evaluating Health-related quality-of-life outcomes in patients with congestive heart failure. A review of recent randomised controlled trials.

Congestive heart failure (CHF) is a chronic disorder characterised by fatigue, shortness of breath and congestion. Treatment is designed to relieve symptoms, halt or delay progression of the disease, prolong life and, ultimately, improve quality of life. The purpose of this paper is to identify recent trends in the assessment of health-related quality-of-life (HR-QOL) outcomes in randomised, controlled trials evaluating treatment effectiveness in patients with CHF. 41 studies using HR-QOL as an explicit outcome and published in English between 1990 and September 1998 were reviewed. Trends in the measurement of HR-QOL and evidence of treatment effectiveness are presented followed by a discussion of the implications for future research. Results suggest that pharmacological and nonpharmacological treatment regimens can have a positive impact on HR-QOL. However, treatment-related improvement in exercise capacity in patients with CHF was not consistently associated with improvement in all domains of HR-QOL. The primary HR-QOL domain affected by treatment appears to be the performance of daily activities, which may or may not be accompanied by enhanced well-being. This suggests that functional status should be considered a primary HR-QOL end-point in clinical intervention trials. Preference-based or utility assessment, ethnic group differences in treatment effectiveness, caregiver burden and cost effectiveness are understudied outcomes in CHF research.

Psychometric properties of the functional performance inventory in patients with chronic obstructive pulmonary disease.

BACKGROUND: The Functional Performance Inventory (FPI) is a subjective measure of the performance dimension of functional status, based on an explicit analytical framework and the experiences of patients themselves. OBJECTIVES: To describe the conceptual foundation of the instrument, the procedures used to maximize content validity, and the results of the initial psychometric testing of the FPI in patients with chronic obstructive pulmonary disease (COPD). METHOD: Items and response structure for the instrument were drawn from the literature and qualitative interviews with 12 men and women with COPD. Twenty-four clinical and scientific experts participated in content validation. To assess the FPI's psychometric characteristics, 154 patients participated in a cross-sectional mail survey; 54 took part in a 2-week reproducibility assessment. Forty relatives were also included in validity testing. RESULTS: The instrument was internally consistent (alpha = .96) and reproducible (ICC = .85). Validity was evident in the significant (p < .001) correlations found between the FPI total score and the Functional Status Questionnaire (activities of daily living, r = .68; instrumental activities of daily living, r = .68), Duke Activity Status Index (r = .61), Bronchitis-Emphysema Symptom Checklist (r = -.59), Basic Need Satisfaction Inventory (r = .61), and Cantril's Ladder of Life Satisfaction (r = .63). The relationship between patient FPI score and relative perception of functioning, using the Katz Adjustment Scale for Relatives, was also significant (socially expected activities, r = .53; free-time activities, r = .49, p < .01). The instrument discriminated between patients with severe and moderate levels of perceived severity and activity limitation (t = 8.52, p <.001) and patients with FEV1 greater than and less than 1.0 liter (t = 4.25, p < .001). CONCLUSIONS: Results suggest that the FPI is a useful measure of functional performance in patients with COPD. Further development of the spiritual activities and work and school domains is in order, as is additional study of the instrument's responsiveness to change.