Effects of pulmonary rehabilitation on physiologic and psychosocial outcomes in patients with chronic obstructive pulmonary disease.
The chronic obstructive pulmonary diseases are major causes of disability and death [1-3]. Health statistics underestimate the prevalence of these diseases because of difficulties in definition and recognition and because of misclassification [4]. Although standard medical therapy can alleviate symptoms, many patients with these diseases must cope with the distressing symptom of breathlessness that results from a chronic, irreversible, and disabling disease. These patients may use services in physician offices, emergency departments, hospitals, and intensive care units, in part because of a lack of understanding and inability to cope with frightening and disabling symptoms. Since a comprehensive care program for patients with chronic obstructive pulmonary disease was first described [5], pulmonary rehabilitation has become an established way to enhance standard therapy to control symptoms, optimize functional capacity, and reduce the medical and economic burdens of patients with disabling chronic lung diseases [6-12]. Comprehensive programs usually include education, instruction in respiratory and chest physiotherapy techniques, psychosocial support, and exercise training [13]. The primary goal of rehabilitation is to restore the patient to the highest possible level of independent function. This is accomplished by helping patients to become more knowledgeable about their disease, more actively involved in their own health care, more independent in performing daily activities, and less dependent on others, including health professionals. Previous studies have shown important benefits of pulmonary rehabilitation, including increased exercise tolerance and quality of life and a decreased number of symptoms and use of health care services [7]. However, many of these findings are based on small numbers of patients and on observational, nonrandomized studies. We compared the effects of comprehensive pulmonary rehabilitation on both physiologic and psychosocial outcomes with the effects of education alone. Our study featured random assignment and long-term, 6-year follow-up. Methods Patients For 18 months, 352 patients with chronic obstructive pulmonary disease were screened for the study; 128 met entry criteria and were randomly assigned to either the comprehensive pulmonary rehabilitation program or an education program (control group). Patients were recruited through mechanisms similar to those used in regular clinical pulmonary rehabilitation, including written and personal contact with physicians and direct advertisement to the general public for persons with breathlessness. Nine patients who initially agreed to participate (6 in the rehabilitation group and 3 in the education group) but who withdrew from the study before completing 2 weeks of the interventions were considered to be pretreatment drop-outs. Reasons for dropping out included concurrent illness (four patients), a too-large time commitment (2 patients), and no clear explanation (3 patients). Patients who dropped out and those who remained in the study did not differ. The remaining 119 patients comprised 32 women and 87 men. The following were the inclusion criteria: 1. Clinical diagnosis of mild to severe chronic obstructive pulmonary disease that was confirmed by history, physical examination, spirometry, measurement of arterial blood gases, and chest roentgenograms. Patients with diagnoses of emphysema, chronic bronchitis, or asthmatic bronchitis were accepted. Patients with primarily acute, reversible airway disease (asthma) but no chronic airflow obstruction were excluded. 2. Stable condition while the patient was receiving an acceptable medical regimen and was under the care of a primary care provider. Patients without a primary care physician who presented for evaluation were referred for appropriate evaluation and treatment before they enrolled in the study. 3. No other significant disabling lung disease, serious heart problems, or other medical condition that would interfere with the patient's participation. Current smokers were not excluded if they showed a commitment to quitting smoking before enrollment. Smoking cessation counseling was incorporated into the rehabilitation program for patients assigned to that group. Experimental Design All eligible patients were randomly assigned to participate in either the comprehensive pulmonary rehabilitation program (n = 57) or the education program (n = 62). The randomization scheme was fixed before the trial with a block size of 8. Assignment was determined by a table of random numbers and was indicated on cards placed in sequentially numbered envelopes that were kept in a central office separate from the study site. Clinical personnel were unaware of the randomization scheme. After a patient agreed to enroll and signed the consent form approved by the University of California, San Diego, Human Subjects Committee, the central office was contacted by telephone and the next numbered envelope was opened. Interventions Pulmonary Rehabilitation Program The comprehensive rehabilitation program included two phases. Phase I (core program) consisted of twelve 4-hour sessions given over 8 weeks. Each session included two periods of classroom or group support and supervised exercise training. The rehabilitation program included four main components: 1. Education. Groups of three to six patients were taught by experienced pulmonary rehabilitation staff and selected guest speakers. Topics included the following: How Normal Lungs Work, What Is Chronic Obstructive Pulmonary Disease?, Medications, Nutrition, Oxygen Therapy, Coping with Stress, Energy-saving Techniques, Self-Care Tips, Travel, Pollution and Environmental Hazards, When To Call Your Doctor, Smoking Cessation Techniques, Planning a Daily Schedule, and Breathing Techniques. 2. Physical and respiratory care instruction. Patients received individual instruction in respiratory care and chest physiotherapy techniques such as postural drainage, pursed lip and diaphragmatic breathing, oxygen therapy, and proper use of respiratory therapy equipment. 3. Psychosocial support. Patients and staff met in weekly group sessions facilitated by a psychiatrist. Spouses or partners of the patients were encouraged to attend. Sessions focused on difficulties commonly faced by patients, such as depression, anxiety, fear, and family or social problems. Relaxation techniques were introduced to help patients better cope with the emotional stress of dyspnea. 4. Supervised exercise training. After the baseline exercise test, each patient received an individualized exercise prescription based on the maximum, symptom-limited level [14]. Patients with severe hypoxemia (Pao2 < 55 mm Hg at rest or < 50 mm Hg with exercise) were trained using supplemental oxygen. The primary exercise-training modality was walking. Training emphasized steady-state exercise consisting of continuous walking at the highest tolerated symptom-limited level for as long as 30 minutes. Patients were initially trained to walk on a motor-driven treadmill under supervision. The staff then instructed patients in translating the target treadmill speed to a pace for free walking. Patients were asked to walk at home at least twice daily and to keep a training log of time, distance, pace (steps per minute), and perceived symptoms of breathlessness and muscle fatigue. Patients were also instructed and trained in upper-extremity exercise using an isokinetic upper-body ergometer during supervised sessions and a progressive program of arm lifts with weights for home training [15]. Patients were asked to do upper-extremity training daily and to keep a daily log. Phase II of the rehabilitation program involved monthly follow-up visits for 1 year. These visits provided reinforcement after the core phase of the program. These sessions included a supervised period of exercise, group sessions to discuss progress and problems, and the introduction of maintenance techniques. Education Control Program The goal of the education program was to conduct a series of health education classes that would provide information similar to that provided in the rehabilitation program, but in a shorter and less intensive program without the behavioral components, individualized instruction, and supervised exercise training. Patients in the education group attended four 2-hour sessions scheduled biweekly for 8 weeks. Each group consisted of approximately 10 to 15 patients. At the beginning of each session, a videotape describing some aspect of chronic obstructive pulmonary disease management was presented [Pulmonary Self-Care Series, Encyclopedia Britannica, Vision Multimedia Communications, Inc., Winter Park, Florida]. The four-part videotape series included the following programs: 1) Learning To Live with a Breathing Problem; 2) Building Your Strength and Endurance; 3) You Can Do It: Clearing Your Airways; and 4) Learning To Breathe Better. Patients also completed life events [16], social support [17], health locus of control [18], and sense of coherence [19] questionnaires and a semistructured smoking interview. The patients then participated in a group discussion about either the material covered in the videotape or the questionnaires. The final hour of the session included a lecture followed by a question and answer period presented by professionals in the fields of pulmonary medicine, pharmacology, respiratory therapy, and nutrition. Assessment Each patient had physiologic and psychosocial function evaluation before intervention (baseline), immediately after the program ended (2 months), and at regular intervals for 72 months. Physiologic measures, including laboratory pulmonary function and maximal treadmill exercise tests, were done 2, 12, 24, 48, and 72 months after the program began. Psychosocial measures and endurance exercise tests were done more frequently at 2, 6, 12, 18, 24, 36, 48, 60, and 72 months. Laboratory tests of pulmon