A systematic review of patient-reported outcome instruments measuring sleep dysfunction in adults.

Sleep dysfunction can manifest in several ways, ranging from insomnia to somnolence, and from disrupted sleep to lack of restful sleep. Measuring sleep dysfunction is an area of active research and there exist a number of patient-reported outcome instruments that measure various aspects of sleep dysfunction. However, these instruments have not been evaluated systematically. We used a conceptual model of sleep that included four physical domains of general interest to patients and investigators, and cover the breadth of this disorder: sleep initiation; sleep maintenance; sleep adequacy; and somnolence. We next considered the additional health-related quality-of-life (HR-QOL) domains of psychological and social functioning, progressing along the continuum to include health perceptions and opportunity. We then conducted a literature review to identify instruments and, using criteria developed by the Medical Outcomes Trust Scientific Advisory Committee, evaluated these instruments for their potential use in measuring sleep dysfunction. Twenty-two instruments were identified. Six instruments were found to include the four physical domains defined a priori (Basic Nordic Sleep Questionnaire, Leeds Sleep Evaluation Questionnaire, Medical Outcomes Study - Sleep Problems Measures, Pittsburgh Sleep Diary, Pittsburgh Sleep Quality Index, Self-Rated Sleep Questionnaire and the Sleep Dissatisfaction Questionnaire). Several additional instruments addressed at least some of the domains and thus may be useful for specific purposes. A few instruments addressed overall HR-QOL, but did not include all four domains of interest (Functional Outcomes of Sleep Questionnaire, Quality of Life in Insomniacs and the Sleep-Wake Activity Inventory). Two instruments had undergone extensive psychometric evaluation (Medical Outcomes Study - Sleep Problems Measures and Pittsburgh Sleep Quality Index), with only the latter reporting information about interpretability. Our review indicates that measuring sleep dysfunction in adults is an area of active research and that much work still needs to be completed, specifically the study of interpretability and the application of patient preferences or item response theory. The specific research focus should dictate instrument selection.

Health state preference assessment in diabetic peripheral neuropathy.

OBJECTIVE: To assess patient preferences for health states associated with diabetic peripheral neuropathy (DPN). DESIGN AND INTERVENTION: Seven health states describing varying stages of disease severity in DPN were developed: mild neuropathy, painful neuropathy, severe neuropathy, minor ulcer, severe ulcer, minor amputation and major amputation. Using a computer interview, both rating scale (RS) and standard gamble (SG) preference scores were elicited from 52 patients with diabetes mellitus. SETTING: A US university medical centre and a Veterans Affairs clinic. STUDY PARTICIPANTS: Adult patients with type 1 and type 2 diabetes mellitus between the ages of 18 and 80 years. Patients were excluded if they had been diagnosed with DPN. RESULTS: Preference scores decreased in accordance with greater symptomatic and functional impairment. Median RS scores ranged from 0.89 to 0.23 for the seven health states. Median SG scores ranged from 0.96 to 0.65. CONCLUSIONS: Patient preferences for health states decrease as a function of increasing disease severity in DPN. The result is robust across the RS and SG methods of preference measurement. These results may be useful in informing policy analyses for resource allocation in patients with diabetes mellitus.

Estimating the effect of changes in body mass index on health state preferences.

OBJECTIVE: To investigate the effect of changes in body mass index (BMI) on health state preferences (HSP). DESIGN: Multiple regression analysis on pooled data from a clinical study, predicting final HSP as a function of changes in BMI and initial HSP, controlling for age and gender. Subgroup analyses according to clinically relevant subgroups were performed. SETTING: Primary care practice sites. PATIENTS: 402 obese patients of varying disease severity. MAIN OUTCOME MEASURES: BMI was operationalised as (weight in kilograms)/ (height in metres)(2). HSP were measured directly as visual analogue scale (VAS) scores, and converted to time trade-off (TTO) scores. RESULTS: A one unit decrease in BMI over a 1-year period was associated with a 0.017 gain in utility units (utils). This estimate is comparable to utility gains observed for other widely used treatments (e.g. revascularisation for intermittent claudication, renal transplantation). It varies little over the observed range of VAS to TTO conversion values, and is a conservative estimate compared with using the unconverted VAS scores. If attempts to use weight reduction treatment in only the patients who successfully meet strict weight reduction targets are successful, the gain in HSP experienced by such patients may exceed this estimate. Patients with BMI values >or=28 with hyperglycaemia appear to have the greatest gain in HSP for a given change in BMI over 1 year. CONCLUSIONS: The effect of weight reduction on HSP can be significant, at least in the short term. Estimates of HSP changes presented herein may be useful in economic evaluations of weight reduction treatments.

Obesity and long-term clinical and economic outcomes in coronary artery disease patients.

OBJECTIVE: Obesity is an important risk factor for coronary artery disease (CAD); however, its effect on acute coronary syndrome (ACS) patients' long-term clinical and economic outcomes has not been quantified. We assessed the impact of increasing body mass index (BMI) on 10-year outcomes for ACS patients. RESEARCH METHODS AND PROCEDURES: ACS patients with significant CAD receiving an initial cardiac catheterization at Duke University Medical Center between 1986 and 1997 were included. Patients with a BMI < 18.5 kg/m(2) were excluded; the remaining patients were classified by BMI as normal, overweight, obese, or very obese. Medical costs were estimated from a prior ACS clinical trial with costs adjusted to 1997 dollars and discounted at 3% per annum. RESULTS: There were 9405 patients with data available for analysis. Follow-up was complete on >95% of patients. Patients who were obese at baseline increased from 20% to 33% between 1986 and 1997. Increased BMI was associated with younger age, multi-morbidity, and less severe CAD at baseline. It was also associated with more clinical events, higher cumulative inpatient medical costs, and significant differences in unadjusted survival at 10 years. However, it was not associated with differences in 10-year survival after adjusting for baseline characteristic differences. DISCUSSION: Obese ACS patients are younger and are hospitalized more frequently during the first 10 years of their illness than are non-obese patients. They also incur higher cumulative inpatient medical costs, especially the very obese. These findings highlight the opportunities for therapeutic benefit that aggressive weight management and secondary prevention may provide this population.