Role of Exercise and Lung Function in Predicting Work Status in Cystic Fibrosis
Department of Medicine, University of British Columbia; McDonald Research Laboratories/iCAPTURE Centre, and Adult Cystic Fibrosis Clinic, St. Paul's Hospital, Vancouver, British Columbia, Canada6uj, http://www.100md.com
ABSTRACT6uj, http://www.100md.com
TOP6uj, http://www.100md.com
ABSTRACT6uj, http://www.100md.com
INTRODUCTION6uj, http://www.100md.com
METHODS6uj, http://www.100md.com
RESULTS6uj, http://www.100md.com
DISCUSSION6uj, http://www.100md.com
REFERENCES6uj, http://www.100md.com
With larger numbers of adult patients with cystic fibrosis (CF) in the workplace, the issue of disability has arisen increasingly. We examined relationships between measures of pulmonary impairment and work/school capability and then determined whether quantification of aerobic fitness improved predictability of disease-related disability. We studied 73 patients with CF who performed lung function and exercise capacity tests, completed a work/education questionnaire, and were scored for clinical and chest radiographic status. Patients who were characterized as unemployed and in poor health had more severe pulmonary disease according to American Thoracic Society impairment/disability criteria. Subjects were further classified into three groups based on employment or education status over the preceding 12 months. FEV1, maximal oxygen consumption, Schwachman–Kulczycki clinical and Brasfield radiographic scores, and frequency of pulmonary exacerbations over 2 years were associated with disability, but change in FEV1 over 2 years and oxygen saturation at rest or exertion were not. FEV1 and Schwachman–Kulczycki scores were the best independent predictors of impairment/disability; specific thresholds used in other pulmonary diseases were of limited utility. We conclude that after accounting for either current level of FEV1 or Schwachman–Kulczycki scores, no other physiological or clinical measures contribute to predicting limitation in a work or school environment.
Key Words: patients with cystic fibrosis • disability • forced expiratory volume • impairmentgg1)h, 百拇医药
INTRODUCTIONgg1)h, 百拇医药
TOPgg1)h, 百拇医药
ABSTRACTgg1)h, 百拇医药
INTRODUCTIONgg1)h, 百拇医药
METHODSgg1)h, 百拇医药
RESULTSgg1)h, 百拇医药
DISCUSSIONgg1)h, 百拇医药
REFERENCESgg1)h, 百拇医药
Advances in both the diagnosis and treatment of cystic fibrosis (CF) have led to substantial increases in survival of this population. As a result, adult patients commonly outnumber pediatric patients with CF. With more adult patients with CF in the workplace and in light of the progressive nature of the disease, the issue of disability inevitably arises. The medical assessment of job performance or determination of potential work restrictions is particularly challenging. The American Thoracic Society (ATS) publication concerning evaluation of impairment/disability represents one of the guidelines used in determining the presence and degree of impairment caused by respiratory disorders (1). This approach uses resting pulmonary function tests and in some instances measures of exercise capacity. Other national and state guidelines for making impairment ratings also exist and also use pulmonary function and exercise test measures. Impairment has been defined as temporary or permanent change in pulmonary function and/or maximal oxygen consumption (O2max) (1). Disability is defined as the effect of impairment in an individual's life. Severe impairment is defined as FEV1% pred < 40%, FVC % pred < 50%, FEV1/FVC < 40%, or diffusing capacity of the lung for CO (DLCO) < 40% (1). Exercise testing is recommended if any of the resting pulmonary function measurements are abnormal and above the energy demand threshold. A patient is characterized as severely impaired if O2max < 15 ml/kg per minute, or if the occupational energy demand exceeds 40% of the patient's O2max (1). Ortega and associates have shown that a combination of resting pulmonary function measurements and exercise performance assessment can more accurately determine impairment in patients with chronic obstructive pulmonary disease (2). These thresholds have not been specifically evaluated in patients with CF. Applicability to this patient group is uncertain given the younger age and effects of other manifestations of this disease.
The aim of our study was threefold: first, to determine the proportion of a cohort of adult patients with CF who are limited in their employment/education on the basis of current ATS impairment criteria; second, to investigate the utility of different measurements of resting pulmonary function and exercise capacity used to apportion impairment caused by other respiratory diseases in patients with CF; and finally, to evaluate the energy cost of the work of patients as a fraction of their measured O2max and relate this to the ATS impairment criteria.;c, 百拇医药
METHODS;c, 百拇医药
TOP;c, 百拇医药
ABSTRACT;c, 百拇医药
INTRODUCTION;c, 百拇医药
METHODS;c, 百拇医药
RESULTS;c, 百拇医药
DISCUSSION;c, 百拇医药
REFERENCES;c, 百拇医药
Sample;c, 百拇医药
We studied 73 stable patients with CF attending the Adult Cystic Fibrosis Clinic at St. Paul's Hospital (Vancouver, BC, Canada). We explained experimental procedures and risks before obtaining written consent, which was approved by the Ethics Committee of the University of British Columbia and St. Paul's Hospital.
Pulmonary Functionhe6s, 百拇医药
Spirometry (FEV1 and FVC) was performed in accordance with ATS criteria (3). Values were expressed as a percentage of normal values (3) and best postbronchodilator measurements were used. Predicted values were calculated from the equations for adults as derived by Crapo and associates (4). Fractional change in FEV1 (i.e., FEV1 = [FEV1(1998) – FEV1(2000)]/FEV1(2000)) was calculated to compare 2-year rates of change in lung function.he6s, 百拇医药
Resting and Exercise Testshe6s, 百拇医药
The O2max test was performed on a Monark (Vansbro, Sweden) stationary bicycle as described previously in Frangolias and Wilcox (5). Resting heart rate and oxygen saturation were measured for a 5-minute interval with subjects sitting before exercise testing.he6s, 百拇医药
Clinical Scoreshe6s, 百拇医药
We calculated Schwachman–Kulczycki (S–K) scores (6) and Brasfield scores (7) at the time of testing and tallied the number of days treated for pulmonary infections over 2 years.
Questionnaire and Patient Grouping(:, 百拇医药
We obtained information about marital status, living arrangements, income sources, education level, and current status related to attending school or employment. We determined employment (full- or part-time) in or outside the home, postsecondary school attendance, and days missed from work/school due to CF-related illness. We obtained employment/school status from medical charts for the remaining patients attending the clinic to evaluate how representative our study sample was of the clinic population. Study subjects were then categorized on the basis of whether they were employed/attended school full-time, were employed/attended school part-time, or were unemployed due to poor health. Study subjects were further categorized on the basis of the ATS impairment criteria for FEV1% pred and O2max (1) into the following categories:(Despina D. Frangolias, Caroline L. Holloway, Sverre Vedal and Pearce G. Wilcox)
ABSTRACT6uj, http://www.100md.com
TOP6uj, http://www.100md.com
ABSTRACT6uj, http://www.100md.com
INTRODUCTION6uj, http://www.100md.com
METHODS6uj, http://www.100md.com
RESULTS6uj, http://www.100md.com
DISCUSSION6uj, http://www.100md.com
REFERENCES6uj, http://www.100md.com
With larger numbers of adult patients with cystic fibrosis (CF) in the workplace, the issue of disability has arisen increasingly. We examined relationships between measures of pulmonary impairment and work/school capability and then determined whether quantification of aerobic fitness improved predictability of disease-related disability. We studied 73 patients with CF who performed lung function and exercise capacity tests, completed a work/education questionnaire, and were scored for clinical and chest radiographic status. Patients who were characterized as unemployed and in poor health had more severe pulmonary disease according to American Thoracic Society impairment/disability criteria. Subjects were further classified into three groups based on employment or education status over the preceding 12 months. FEV1, maximal oxygen consumption, Schwachman–Kulczycki clinical and Brasfield radiographic scores, and frequency of pulmonary exacerbations over 2 years were associated with disability, but change in FEV1 over 2 years and oxygen saturation at rest or exertion were not. FEV1 and Schwachman–Kulczycki scores were the best independent predictors of impairment/disability; specific thresholds used in other pulmonary diseases were of limited utility. We conclude that after accounting for either current level of FEV1 or Schwachman–Kulczycki scores, no other physiological or clinical measures contribute to predicting limitation in a work or school environment.
Key Words: patients with cystic fibrosis • disability • forced expiratory volume • impairmentgg1)h, 百拇医药
INTRODUCTIONgg1)h, 百拇医药
TOPgg1)h, 百拇医药
ABSTRACTgg1)h, 百拇医药
INTRODUCTIONgg1)h, 百拇医药
METHODSgg1)h, 百拇医药
RESULTSgg1)h, 百拇医药
DISCUSSIONgg1)h, 百拇医药
REFERENCESgg1)h, 百拇医药
Advances in both the diagnosis and treatment of cystic fibrosis (CF) have led to substantial increases in survival of this population. As a result, adult patients commonly outnumber pediatric patients with CF. With more adult patients with CF in the workplace and in light of the progressive nature of the disease, the issue of disability inevitably arises. The medical assessment of job performance or determination of potential work restrictions is particularly challenging. The American Thoracic Society (ATS) publication concerning evaluation of impairment/disability represents one of the guidelines used in determining the presence and degree of impairment caused by respiratory disorders (1). This approach uses resting pulmonary function tests and in some instances measures of exercise capacity. Other national and state guidelines for making impairment ratings also exist and also use pulmonary function and exercise test measures. Impairment has been defined as temporary or permanent change in pulmonary function and/or maximal oxygen consumption (O2max) (1). Disability is defined as the effect of impairment in an individual's life. Severe impairment is defined as FEV1% pred < 40%, FVC % pred < 50%, FEV1/FVC < 40%, or diffusing capacity of the lung for CO (DLCO) < 40% (1). Exercise testing is recommended if any of the resting pulmonary function measurements are abnormal and above the energy demand threshold. A patient is characterized as severely impaired if O2max < 15 ml/kg per minute, or if the occupational energy demand exceeds 40% of the patient's O2max (1). Ortega and associates have shown that a combination of resting pulmonary function measurements and exercise performance assessment can more accurately determine impairment in patients with chronic obstructive pulmonary disease (2). These thresholds have not been specifically evaluated in patients with CF. Applicability to this patient group is uncertain given the younger age and effects of other manifestations of this disease.
The aim of our study was threefold: first, to determine the proportion of a cohort of adult patients with CF who are limited in their employment/education on the basis of current ATS impairment criteria; second, to investigate the utility of different measurements of resting pulmonary function and exercise capacity used to apportion impairment caused by other respiratory diseases in patients with CF; and finally, to evaluate the energy cost of the work of patients as a fraction of their measured O2max and relate this to the ATS impairment criteria.;c, 百拇医药
METHODS;c, 百拇医药
TOP;c, 百拇医药
ABSTRACT;c, 百拇医药
INTRODUCTION;c, 百拇医药
METHODS;c, 百拇医药
RESULTS;c, 百拇医药
DISCUSSION;c, 百拇医药
REFERENCES;c, 百拇医药
Sample;c, 百拇医药
We studied 73 stable patients with CF attending the Adult Cystic Fibrosis Clinic at St. Paul's Hospital (Vancouver, BC, Canada). We explained experimental procedures and risks before obtaining written consent, which was approved by the Ethics Committee of the University of British Columbia and St. Paul's Hospital.
Pulmonary Functionhe6s, 百拇医药
Spirometry (FEV1 and FVC) was performed in accordance with ATS criteria (3). Values were expressed as a percentage of normal values (3) and best postbronchodilator measurements were used. Predicted values were calculated from the equations for adults as derived by Crapo and associates (4). Fractional change in FEV1 (i.e., FEV1 = [FEV1(1998) – FEV1(2000)]/FEV1(2000)) was calculated to compare 2-year rates of change in lung function.he6s, 百拇医药
Resting and Exercise Testshe6s, 百拇医药
The O2max test was performed on a Monark (Vansbro, Sweden) stationary bicycle as described previously in Frangolias and Wilcox (5). Resting heart rate and oxygen saturation were measured for a 5-minute interval with subjects sitting before exercise testing.he6s, 百拇医药
Clinical Scoreshe6s, 百拇医药
We calculated Schwachman–Kulczycki (S–K) scores (6) and Brasfield scores (7) at the time of testing and tallied the number of days treated for pulmonary infections over 2 years.
Questionnaire and Patient Grouping(:, 百拇医药
We obtained information about marital status, living arrangements, income sources, education level, and current status related to attending school or employment. We determined employment (full- or part-time) in or outside the home, postsecondary school attendance, and days missed from work/school due to CF-related illness. We obtained employment/school status from medical charts for the remaining patients attending the clinic to evaluate how representative our study sample was of the clinic population. Study subjects were then categorized on the basis of whether they were employed/attended school full-time, were employed/attended school part-time, or were unemployed due to poor health. Study subjects were further categorized on the basis of the ATS impairment criteria for FEV1% pred and O2max (1) into the following categories:(Despina D. Frangolias, Caroline L. Holloway, Sverre Vedal and Pearce G. Wilcox)