The development of a comorbidity index with physical function as the outcome

A computerized adaptive test for patients with hip impairments produced valid and responsive measures of function

OBJECTIVES

To describe the use of a computerized adaptive test (CAT) in routine clinical practice and evaluate content coverage and construct validity, sensitivity to change, and responsiveness of hip CAT functional status (FS) measures.

DESIGN

Longitudinal, prospective observational cohort study.

SETTING

Two hundred fifty-seven outpatient rehabilitation clinics in 31 states (United States).

PARTICIPANTS

Two samples were examined: intake and discharge rehabilitation FS data from patients (N=8714) treated for hip impairments between January 2005 and June 2007 and data from patients (N=444) used to develop the hip CAT were examined for comparison (2002-2004).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Hip functional status and global rating of change.

RESULTS

The CAT used on average 7 items to produce precise estimates of FS that adequately covered the content range with negligible floor and slight ceiling effects. Test information functions and SEs supported FS measure precision. FS measures discriminated patients in clinically logical ways. Sixty-one percent of patients obtained discharge FS measures greater than or equal to minimal detectable change (95% confidence intervals). Change of 6 FS units (scale: 0-100) represented minimal clinically important improvement, which 64% of patients obtained.

CONCLUSIONS

The hip CAT was efficient; produced valid, responsive measures of FS for patients receiving therapy for hip impairments; and functioned well in routine clinical application but would benefit from more difficult items.

Muscle power is related to tibial bone strength in older women

We enrolled 65 to 75 year-old community-dwelling women and measured muscle power, strength, physical activity using accelerometry and tibial bone strength using peripheral quantitative computed tomography (pQCT). Muscle power contributed 6.6% of the variance in the bone strength-strain index and 8.9% in the section modulus after accounting for age, height, weight, and physical activity; moderate to vigorous physical activity was related to muscle power in the lower extremity.

INTRODUCTION

Muscle power is associated with DXA measurements of bone mass, but it is not known whether muscle power is associated with bone strength. There are no reports of investigations that have tested the effect of muscle power on bone compartments using advanced imaging.

METHODS

We enrolled 74 community-dwelling women aged 65-75 years. We measured muscle power and strength of leg extension using Keiser air-pressure resistance equipment. All participants wore a waist-mounted Actigraph accelerometer to record physical activity. We used peripheral quantitative computed tomography (pQCT) to measure tibial mid-shaft (50% of the site) bone strength (strength-strain index, section modulus). We used Pearson correlations and multi-level linear regression to investigate the associations between muscle and bone.

RESULTS

Muscle power contributed 6.6% (p = 0.007) of the variance in the bone strength-strain index and 8.9% (p = 0.001) the variance in the section modulus in older women after accounting for age, height, weight, and physical activity. Moderate to vigorous physical activity was significantly related to muscle power in the lower extremity (r = 0.260; p = 0.041).

CONCLUSION

Muscle power significantly contributed to the variance in estimated bone strength. Whether power training will prove to be a more effective stimulus for bone strength than conventional strength training will require further studies.

Increased risk of falling in older community-dwelling women with mild cognitive impairment

BACKGROUND

Falls are a major health care problem for older people and are associated with cognitive dysfunction. Mild cognitive impairment (MCI) is an increasingly recognized clinical problem. No study has comprehensively compared people with and without MCI for fall risk factors in both the physiological and cognitive domains.

OBJECTIVE

The purpose of this cross-sectional study was to comprehensively compare fall risk factors in community-dwelling older women with and without MCI.

DESIGN

A cross-sectional design was used in the study.

METHODS

Community-dwelling women (N=158) with Folstein Mini Mental State Examination scores of >or=24 participated in the study. The Montreal Cognitive Assessment (MoCA) was used to categorize participants as either having or not having MCI. Each participant's fall risk profile was assessed with the Physiological Profile Assessment (PPA). Three central executive functions were assessed: (1) set shifting was assessed with the Trail Making Test (part B), (2) updating (ie, working memory) was assessed with the Verbal Digits Backward Test, and (3) response inhibition was assessed with the Stroop Colour-Word Test.

RESULTS

Both the composite PPA score and its subcomponent, postural sway performance, were significantly different between the 2 groups; participants with MCI had higher composite PPA scores and greater postural sway compared with participants without MCI. Participants with MCI performed significantly worse on all 3 central executive function tests compared with participants without MCI.

LIMITATIONS

A screening tool was used to categorize participants as having MCI, and fall risk factors were compared rather than the actual incidence of falls.

CONCLUSIONS

Fall risk screening may be prudent in older adults with MCI.

Sense of coherence as a resource in relation to health-related quality of life among mentally intact nursing home residents - a questionnaire study

BACKGROUND

Sense of coherence (SOC) is a strong determinant of positive health and successful coping. For older people living in the community or staying in a hospital, SOC has been shown to be associated with health-related quality of life (HRQOL). Studies focusing on this aspect among nursing home (NH) residents have been limited. This study investigated the relationship between SOC and HRQOL among older people living in NHs in Bergen, Norway.

METHODS

Based on the salutogenic theoretical framework, we used a descriptive correlation design using personal interviews. We collected data from 227 mentally intact NH residents for 14 months in 2004-2005. The residents' HRQOL and coping ability were measured using the SF-36 Health Survey and the Sense of Coherence Scale (SOC-13), respectively. We analyzed possible relationships between the SOC-13 variables and SF-36 subdimensions, controlling for age, sex, marital status, education and comorbidity, and investigated interactions between the SOC and demographic variables by using multiple regression.

RESULTS

SOC scores were significantly correlated with all SF-36 subscales: the strongest with mental health (r = 0.61) and the weakest with bodily pain (r = 0.28). These did not change substantially after adjusting for the associations with demographic variables and comorbidity. SOC-13 did not interact significantly with the other covariates.

CONCLUSION

These findings suggest that more coping resources improve HRQOL. This may indicate the importance of strengthening the residents' SOC to improve the perceived HRQOL. Such knowledge may help the international community in developing nursing regimens to improve HRQOL for older people living in NHs.

The impact of social support and sense of coherence on health-related quality of life among nursing home residents--a questionnaire survey in Bergen, Norway

BACKGROUND AND OBJECTIVES

Few studies have examined the association between social support and health-related quality of life (HRQOL) among nursing home residents and whether the sense of coherence (SOC) modifies the effect of social support on health-related quality of life. The main aims of this study were to determine the relationship between social support and HRQOL and to investigate whether the SOC modifies the effect of social support on HRQOL.

DESIGN

A cross-sectional, descriptive, correlational design.

SETTINGS

All 30 nursing homes in Bergen in western Norway.

PARTICIPANTS

Two hundred and twenty-seven mentally intact long-term nursing home residents 65 years and older.

METHODS

Data were obtained through face-to-face interviews using the SF-36 Health Survey, Social Provisions Scale and Sense of Coherence Scale. Possible relationships between the Social Provisions Scale and the eight SF-36 subdimensions were analysed using multiple linear regression while controlling for age, sex, marital status, education and comorbid illness. Interactions between the Sense of Coherence Scale and Social Provisions Scale were investigated.

RESULTS

Attachment affected the mental health subdimension (p=0.001), opportunity for nurturance affected social functioning (p=0.003) and reassurance of worth affected vitality (p=0.001) after adjustment for demographic variables and comorbid illness. After the analysis included the sense of coherence, nurturance still significantly affected social functioning and reassurance of worth still significantly affected vitality. No interaction with sense of coherence was found, and sense of coherence significantly affected all SF-36 subdimensions.

CONCLUSIONS

The opportunity to provide nurturance for others appears to be important for social functioning, and sense of competence and sense of self-esteem appear to be important for vitality. Further, the residents' relationships with significant others comprise an important component of mental health. Finally, independent of the level of sense of coherence, social support is an important resource for better health-related quality of life. Clinical nurses should recognize that social support is associated with health-related quality of life and pay attention to the importance of social support for the residents in daily practice.

Computerized adaptive test for patients with foot or ankle impairments produced valid and responsive measures of function

OBJECTIVE

We tested the item response theory (IRT) model assumptions of the original item bank, and evaluated the practical and psychometric adequacy, of a computerized adaptive test (CAT) for patients with foot or ankle impairments seeking rehabilitation in outpatient therapy clinics.

METHODS

Data from 10,287 patients with foot or ankle impairments receiving outpatient physical therapy were analyzed. We first examined the unidimensionality, fit, and invariance IRT assumptions of the CAT item bank. Then we evaluated the efficiency of the CAT administration and construct validity and sensitivity of change of the foot/ankle CAT measure of lower-extremity functional status (FS).

RESULTS

Results supported unidimensionality, model fit, and invariance of item parameters and patient ability estimates. On average, the CAT used seven items to produce precise estimates of FS that adequately covered the content range with negligible floor and ceiling effects. Patients who were older, had more chronic symptoms, had more surgeries, had more comorbidities, and did not exercise prior to receiving rehabilitation reported worse discharge FS. Seventy-one percent of patients obtained statistically significant change at follow-up. Change of 8 FS units (scale 0-100) represented minimal clinically important improvement.

CONCLUSIONS

We concluded that the foot/ankle item bank met IRT assumptions and that the CAT FS measure was precise, valid, and responsive, supporting its use in routine clinical application.

Validation of the Charlson Comorbidity Index for predicting functional outcome of stroke

OBJECTIVE

To determine whether a separate comorbidity index is needed to predict functional outcome after stroke, we compared the predictability of the Charlson Comorbidity Index (CMI) and the Functional Comorbidity Index (FCI) to that of a stroke-specific comorbidity index with function quantified with a measure developed with a Rasch model as outcome.

DESIGN

Two prospective inception cohort studies, in 1996 through 1998 and in 2002 through 2005, with up to 9 months of follow-up.

SETTING

Participants enrolled in 2 studies were recruited from acute care hospitals in the Montreal area.

PARTICIPANTS

For study one, 1027 persons with a first stroke discharged into the community were eligible; the 437 who were interviewed a second time at 6 months were included in the analysis. In study two, 235 of 262 patients with stroke were enrolled.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

To predict recovery, we developed 3 stroke-specific comorbidity algorithms based on the estimated strength of association between comorbidities and stroke function. The various indices were compared on the basis of their predictive ability with a c statistic.

RESULTS

In study 1, the c statistics were .758, .763, .766, and .763 for the stroke-specific algorithms 1, 2, and 3 and the CMI, respectively. In study 2, the c statistics were .680, .700, .704, .714, and .714 for the algorithms 1, 2, and 3, the CMI, and the FCI, respectively.

CONCLUSIONS

For purposes of case-mix adjustment, the CMI seems to be more than adequate.

Computerized adaptive test for patients with knee impairments produced valid and responsive measures of function

OBJECTIVE

Assess practicality of using a computerized adaptive test (CAT) in routine clinical practice, perform a psychometric evaluation of content range coverage and test precision, and assess known group construct validity, sensitivity to change and responsiveness of knee CAT functional status (FS) measures.

STUDY DESIGN AND SETTING

Secondary analysis of retrospective intake and discharge rehabilitation FS data collected in a prospective cohort study. Data represented a convenience sample of 21,896 patients with knee impairments receiving outpatient physical therapy in 291 clinics in 30 U.S. states (2005-2007).

RESULTS

The CAT used an average of seven items to produce precise estimates of FS that adequately covered the content range with negligible floor and ceiling effects. Test information functions and standard errors supported FS measure precision. FS measures discriminated patients by age, symptom acuity, surgical history, condition complexity, and prior exercise history in clinically logical ways. Seventy-two percent of patients obtained discharge FS measures > or = minimal detectable change (95% confidence interval). Change of 9 FS units (0-100 scale) represented minimal clinically important improvement, which 67% of patients obtained.

CONCLUSION

The knee CAT was efficient and produced precise, valid, and responsive measures of FS for patients receiving therapy for knee impairments and functioned well in routine clinical application.

A long-term follow-up study investigating health-related quality of life and resource use in survivors of severe sepsis: comparison of recombinant human activated protein C with standard care

Introduction

Recombinant human activated protein C (APC) therapy has been shown to reduce short-term mortality in patients with severe sepsis. However, survivors of sepsis may have long-term complications affecting health-related quality of life (HRQoL) and resource utilization. The objective of this study was to evaluate prospectively the effect of APC on long-term HRQoL and resource utilization compared with a nonrandomized control group that received standard care.

Methods

This was an observational cohort study at nine Canadian intensive care units. Patients with severe sepsis who survived to 28 days were recruited. Patients who received APC formed the treatment group and those that did not formed the standard care group. Patients who did not receive APC because of central nervous system bleeding risk were excluded from the standard care group. HRQoL (determined using the 36-item Short Form) and resource use were recorded at 28 days, and 3, 5 and 7 months.

Results

One hundred patients were enrolled (64 in the standard care group and 36 in the APC group), with 70 patients completing all follow-up visits. Over the 6 months of follow up, APC-treated patients exhibited statistically significantly better scores for the physical component score (P = 0.04) and trends toward improvements in physical functioning (P = 0.12), role physical (P = 0.10) and bodily pain (P = 0.14) as compared with standard care patients. Shorter hospital length of stay was observed for the APC group (36 days versus 48 days; P = 0.05).

Conclusion

These findings challenge earlier assumptions suggesting equivalent HRQoL and resource use in APC-treated and standard care patients who survive severe sepsis.

Comorbidities in rheumatoid arthritis

Rheumatoid arthritis (RA) is often characterized by the burden of swollen joints, pain, and decreased physical function, but less understood are the many manifestations of additional health conditions that are associated with RA and its treatments. First brought to light with observations of increased mortality in RA, studies noted the increased rates of cardiovascular and infection events. The chronic, debilitating, autoimmune nature of RA affects the patient directly or indirectly in almost all organ systems, from cardiovascular problems and infections to depression and gastrointestinal ulcers. On average, the established RA patient has two or more comorbid conditions. It should be the responsibility of the rheumatologist to take these and the risk of additional conditions into account when treating the patient. This chapter reviews important comorbidities in patients with RA, their prevalence, and their relation to RA.

KRD. The Charlson comorbidity index (CCI) for adjustment of hip fracture mortality in the elderly: analysis of the importance of recording secondary diagnoses

This study evaluates the role of the number of secondary diagnoses for calculating the Charlson comorbidity index (CCI) in risk adjustment of the 90-day mortality rate after hip fracture surgical repair. Comorbidities were selected by reviewing the medical records of 390 patients 50 years of age or older in a teaching hospital in Rio de Janeiro from 1995 to 2000. Logistic regression models were fitted including the variables age, sex, and CCI. The CCI was calculated based on: (1) all patients' comorbidities; (2) only the comorbidity with the highest weight; and (3) a single randomly selected comorbidity. There was a gradient in the prediction of the CCI mortality rate when all comorbidities were used (OR = 6.53; 95%CI: 2.27-18.77, for scores <FONT FACE=Symbol>³</FONT> 3). The predictive capacity of the CCI was observed even when it was calculated using only one comorbidity: with the highest weight (OR = 2.83; 95%CI: 1.11-7.22); and randomly selected (OR = 2.90; 95%CI: 1.07-7.81). Using all comorbidities for CCI calculation is important. Severity indices based on a single comorbidity can be useful for risk adjustment procedures.

The National Study on Costs and Outcomes of Trauma

The National Study on the Costs and Outcomes of Trauma Care (NSCOT) was designed to address the need for better information on the value of trauma center care. It is a multi-institutional, prospective study that involved the examination of costs and outcomes of care received by over 5,000 adult trauma patients 18 to 84 years of age treated at 69 hospitals located in 12 states. The study had three major objectives: (1) to examine variations in care provided to trauma patients in Level I trauma centers and nontrauma center hospitals; (2) to determine the extent to which differences in care correlate with patient outcome, where outcome is defined not just in terms of mortality and morbidity, but also in terms of major functional outcomes at 3 months and 12 months after injury; and (3) to estimate acute and 1-year treatment costs for trauma center and nontrauma center care, and to describe the relationship between costs and effectiveness for trauma centers and nontrauma centers. In this article, we describe the design of the NSCOT study and point to some of the methodological challenges faced in its implementation and in the analysis of the data. We also present a description of the study population to serve as a basis of future reports. We conclude with lessons learned and some recommendations for future research.

The impact of trauma-center care on functional outcomes following major lower-limb trauma

BACKGROUND

Although studies have shown that treatment at a trauma center reduces a patient's risk of dying following major trauma, important questions remain as to the effect of trauma centers on functional outcomes, especially among patients who have sustained major lower-limb trauma.

METHODS

Domain-specific scores on the Medical Outcomes Study Short Form Health Survey (SF-36) supplemented by scores on the mobility subscale of the Musculoskeletal Function Assessment (MFA) and the Revised Center for Epidemiologic Studies Depression Scale (CESD-R) were compared among patients treated in eighteen hospitals with a level-I trauma center and fifty-one hospitals without a trauma center. Included in the study were 1389 adults, eighteen to eighty-four years of age, with at least one lower-limb injury with a score of >/=3 points according to the Abbreviated Injury Scale (AIS). To account for the competing risk of death, we estimated the survivors' average causal effect. Estimates were derived for all patients with a lower-limb injury and separately for a subset of patients without associated injuries of the head or spinal cord.

RESULTS

For patients with a lower-limb injury resulting from a high-energy force, care at a trauma center yielded modest but clinically meaningful improvements in physical functioning and overall vitality at one year after the injury. After adjustment for differences in case mix and the competing risk of death, the average differences in the SF-36 physical functioning and vitality scores and the MFA mobility score were 7.82 points (95% confidence interval: 2.65, 12.98), 6.80 points (95% confidence interval: 2.53, 11.07), and 6.31 points (95% confidence interval: 0.25, 12.36), respectively. These results were similar when the analysis was restricted to patients without associated injuries to the head or spine. Treatment at a trauma center resulted in negligible differences in outcome for the subset of patients with injuries resulting from low-energy forces.

CONCLUSIONS

This study provides evidence that patients who sustain high-energy lower-limb trauma benefit from treatment at a level-I trauma center.

Impact of fatty liver disease on health care utilization and costs in a general population: a 5-year observation

BACKGROUND & AIMS

Fatty liver disease is a common condition in the Western world. Fatty liver may progress to steatohepatitis and cirrhosis. It is not yet known whether fatty liver disease results in higher health care utilization and costs.

METHODS

We used data from the Study of Health in Pomerania (SHIP), Germany, to assess the relation of fatty liver disease to self-reported health care utilization and costs at baseline and 5 years. The SHIP is a general population cohort study of 4310 adults aged 20 to 79 years at baseline in Pomerania. Fatty liver disease was defined as the presence of a hyperechogenic pattern of the liver and elevated serum alanine aminotransferase (ALT) levels.

RESULTS

In multivariable analyses, average annual overall health care costs at baseline and follow-up measurement were significantly higher for individuals with sonographic fatty liver and increased serum ALT levels. For example, controlling for comorbid conditions, subjects with sonographic fatty liver disease and increased serum ALT levels had 26% higher overall health care costs at 5-year follow-up. Analyses also suggest that diabetes and cardiovascular disease might mediate the relation of fatty liver disease and health care utilization and costs.

CONCLUSIONS

Policies seeking to minimize costs associated with fatty liver disease might want to consider addressing behavioral risk factors of fatty liver disease.

Predictors of functional performance in community-dwelling people with COPD

PURPOSE

To identify physiologic, well-being, and coping resource predictors of functional performance in community-dwelling people with COPD.

DESIGN

A cross-sectional, correlational design was used with a convenience sample of 119 people who received care in a private pulmonary medicine practice.

METHODS

Participants were recruited in person, completed the study instruments at home, and returned the instruments to the researcher by mail. Pulmonary function test results were obtained from medical records. Univariate, bivariate, and multiple regression analyses were performed.

FINDINGS

Several bivariate correlations were robust, particularly among the well-being and coping resource variables, but none were large enough to indicate multicollinearity. Four proposed predictors (depression, severity of pulmonary disease, age, and gender) explained 46.3% of the variance in functional performance.

CONCLUSIONS

Functional performance was influenced by both physiologic and negative well-being factors. Because of the potential influence of depression on adherence to medical regimen, attention to both physical and mental health is necessary for maintaining optimal health and functioning in these chronically ill people.

Excess use of general practitioners by obese adults: Does health-related quality of life account for the association?

As general practitioners (GP) are seeing, and are likely to continue to see, increasing numbers of obese patients in their practices, it is relevant to know with which needs these patients enter general practice. The present study aims to determine whether besides physical comorbidities, health-related quality of life (HRQOL) accounts for associations of obesity with GP use. In a general population survey in Augsburg, Germany (KORA-Survey S4 1999/2001), anthropometric body mass (BMI in kg/(m(2))), physical comorbidities, HRQOL (the 12-item Short Form; SF-12), and visits to GP were assessed, and analyzed by logistic and zero-truncated negative binomial regressions (two-part model). Gender, age, socio-economic status, marital status, health insurance, and place of residence were adjusted for. The sample consisted of N = 942 residents aged 25 - 74, who had been randomly sampled from 17 cluster-sampled communities, and were either normal-weight, overweight, moderately obese, or severely obese. The moderately obese group had higher odds than the normal-weight to report any GP use; however, while being predictive, neither physical comorbidity nor HRQOL mediated this. In contrast, with regard to number of GP visits among users, the severely obese group (BMI >/= 35) reported significantly more visits than the normal-weight group, and both physical comorbidity and physical (but not mental) HRQOL accounted for this. In conclusion, physical comorbidity and HRQOL mediate excess use of GP by severely obese users in terms of number of visits. Thus, for this group, subjective physical health seems to be important besides physical comorbidities, suggesting for general practice to focus both on evaluated and perceived needs of these patients.

Screening Evaluation System--Europe (SESy_Europe) met skin cancer screening

Skin tumors are the most frequent malignancies in the white population worldwide and have reached the proportion of an epidemic disease. Since non-melanocytic skin cancers can be cured when timely detected, given that still malignant melanoma may have good prognosis if early diagnosed, and considering the key role of primary care in cancer screening advising and implementation, the international PACMeR study group (trial_01.3) adjourned SESy_Europe database in a version comprehensive of skin-malignancies screening indexing. The novel database provides standardized pre-codified translations of 2,331 parameters in eight languages (English, French, German, Greek, Italian, Romanian, Spanish and Turkish) and records the time elapsed from last skin examination, cause and frequency of skins examinations and stratifies skin cancer risk patterns by a systematic registering of risk factors. A comprehensive indexing of skin cancer screening practices among European countries may in fact turn helpful in programming future health policy and tailoring interventions.

Use of medical doctors, physical therapists, and alternative practitioners by obese adults: does body weight dissatisfaction mediate extant associations?

OBJECTIVE

The objective of this study was to assess the association of obesity with the utilization of general practitioners (GP), medical specialists (MS), physical therapists (PT), and alternative practitioners (AP), and to elucidate whether body weight dissatisfaction mediates extant associations.

METHODS

In an adult population survey (KORA Survey S4 1999/2001) in Augsburg, Germany, anthropometric body mass [body mass index (BMI), kg/m(2)], utilization, physical comorbidities, functional limitations due to body weight, and body weight dissatisfaction were assessed and analyzed via multiple logistic regressions.

RESULTS

Obese adults (BMI>or=30) had around double odds of AP, GP, and PT utilization. Regarding AP and, to a lesser extent, PT, body weight dissatisfaction both had direct effects and mediated excess utilization. Most notably, the odds for AP use were about twofold in those who were dissatisfied, and the association of obesity and AP use diminished when adjustment for dissatisfaction was performed. Among overweight participants (25<or=BMI<30), only PT use was elevated and tended to be mediated by dissatisfaction as well.

CONCLUSION

Body weight dissatisfaction mediates obesity-attributable utilization of nonmedical health care providers, especially AP. Possibly, dissatisfaction leads to demands for psychosocial care that is expected to be offered by complementary and allied health professions. For health services utilization research, results call for a scrutiny of body weight dissatisfaction-a known barrier to adopting long-term healthy lifestyles. For practice, results indicate that AP and PT may have special opportunities to encourage the use of preventive services by obese adults.

Assessment of Long-Term Physical Function in Acute Respiratory Distress Syndrome (ARDS) Patients

OBJECTIVE

It is often important to adjust for the effect of comorbid diseases on patient outcomes. This study compares the association between physical function in acute respiratory distress syndrome patients with scores on two comorbidity indices, the Charlson Comorbidity Index, designed to predict mortality, and the Functional Comorbidity Index (FCI), which was designed to predict physical function.

DESIGN

This is a prospective, longitudinal, observational study. A total of 73 survivors of acute respiratory distress syndrome were contacted at 3, 6, and 12 mos. Patient comorbidity was evaluated with the Charlson Comorbidity Index and the FCI. Physical function was measured using the Medical Outcomes Study 36-Item Short Form Health Survey Physical Function Subscale and the Physical Component Subscale scores.

RESULT

Mean FCI and Charlson Comorbidity Index scores correlated fairly strongly (Spearman rho = 0.62, P < 0.001). FCI, but not the Charlson Comorbidity Index, scores correlated with the Physical Function Subscale and Physical Component Subscale scores. After controlling for other potentially confounding variables such as age and severity of illness through regression analysis, the FCI score was still significantly associated with both Physical Function Subscale and Physical Component Subscale scores.

CONCLUSIONS

The FCI is a better method of measuring comorbidity with physical function as the outcome. This study illustrates the importance of choosing the most appropriate comorbidity index for the outcome of interest.

Use of Peak Oxygen Consumption in Predicting Physical Function and Quality of Life in COPD Patients

OBJECTIVE

To determine whether peak oxygen consumption (Vo(2)peak) adds to the power of FEV(1) in predicting physical function and quality of life in COPD patients.

DESIGN

Single-center cross-sectional study.

METHODS

Subjects included 291 COPD patients who completed pulmonary function testing, a graded exercise test, a 6-min walk, and stair climb test to assess physical function; a questionnaire assessing self-reported physical function; and a disease-specific, health-related quality-of-life questionnaire. Hierarchical multiple regression analysis was used to determine the contribution of Vo(2)peak in predicting physical function and quality of life after accounting for FEV(1).

RESULTS

After accounting for FEV(1), Vo(2)peak added significantly to the prediction of 6-min walk distance (R(2) increased by 0.395 [p < 0.005]); stair climb time (R(2) increased by 0.262 [p < 0.005]); self-reported function (R(2) increased by 0.109 [p < 0.005]); and health-related quality-of-life domain of mastery (R(2) increased by 0.044 [p < 0.005]). Only Vo(2)peak was found to significantly predict the health-related quality-of-life domain of fatigue (R(2) = 0.094 [p < 0.005]).

CONCLUSION

After controlling for FEV(1), Vo(2)peak adds significantly to the prediction of physical function and health-related quality-of-life domain of mastery in COPD patients. These results provide additional support for the use of Vo(2)peak in the multidimensional assessment of COPD patients.

Health related quality of life outcome instruments

Health is the most significant part of quality of life. Generally, quality of life outcome instruments used in healthcare confine their attention to health related areas, assessing health related quality of life. The present study aims to describe some commonly used health profile instruments such as the generic measures SF-36, Nottingham Health Profile and Sickness Impact Profile; and the preference-based measures EuroQol and SF-6D. The latter preference-based instruments are increasingly used in outcome studies and obtained data might be used for calculating quality-adjusted life-years.

Comparative assessment of three different indices of multimorbidity for studies on health-related quality of life

BACKGROUND

Measures of multimorbidity are often applied to source data, populations or outcomes outside the scope of their original developmental work. As the development of a multimorbidity measure is influenced by the population and outcome used, these influences should be taken into account when selecting a multimorbidity index. The aim of this study was to compare the strength of the association of health-related quality of life (HRQOL) with three multimorbidity indices: the Cumulative Illness Rating Scale (CIRS), the Charlson index (Charlson) and the Functional Comorbidity Index (FCI). The first two indices were not developed in light of HRQOL.

METHODS

We used data on chronic diseases and on the SF-36 questionnaire assessing HRQOL of 238 adult primary care patients who participated in a previous study. We extracted all the diagnoses for every patient from chart review to score the CIRS, the FCI and the Charlson. Data for potential confounders (age, sex, self-perceived economic status and self-perceived social support) were also collected. We calculated the Pearson correlation coefficients (r) of the SF-36 scores with the three measures of multimorbidity, as well as the coefficient of determination, R2, while controlling for confounders.

RESULTS

The r values for the CIRS (range: -0.55 to -0.18) were always higher than those for the FCI (-0.47 to -0.10) and Charlson (-0.31 to -0.04) indices. The CIRS explained the highest percent of variation in all scores of the SF-36, except for the Mental Component Summary Score where the variation was not significant. Variations explained by the FCI were significant in all scores of SF-36 measuring physical health and in two scales evaluating mental health. Variations explained by the Charlson were significant in only three scores measuring physical health.

CONCLUSION

The CIRS is a better choice as a measure of multimorbidity than the FCI and the Charlson when HRQOL is the outcome of interest. However, the FCI may provide a good option to evaluate the physical aspect of HRQOL for the ease in its administration and scoring. The Charlson index may not be recommended as a measure of multimorbidity in studies related to either physical or mental aspects of HRQOL.