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Patient centered outcomes for pulmonary rehabilitation programs

This is an excerpt from Guidelines for Pulmonary Rehabilitation Programs 6th Edition by AACVPR.

By Gerene Bauldoff, PhD, RN, MAACVPR; Brian Carlin, MD, MAACVPR

As established by AACVPR, patient-centered outcomes address, at a minimum, three essential areas: functional status, exercise capacity, dyspnea, and health-related quality of life (health status). Other outcome assessments such as measures of other symptoms (fatigue), psychosocial screening, or exercise capacity may also be indicated, depending on the needs of the patient and the resources of the program. Psychosocial and nutritional outcome screening, assessment, and intervention are discussed in chapters 5 and 6. A list of required outcome areas and AACVPR-approved measurement tests and instruments is outlined in table 7.1.

Patients are unique and obtain varying degrees of benefits from a program. The evaluation of individual patient progress is a core component of pulmonary rehabilitation. However, many standardized outcome measures tell providers how groups of people performed, not how an individual patient performed. For this reason, statistical measures of outcomes such as minimal clinically important differences (MCID) are used as a broad guide for program achievement, not as a standard of the minimal level that a particular patient must achieve. However, MCID is an appropriate benchmark when establishing program performance. See chapter 12 for program performance discussion.

Assessment of individual patient progress ultimately depends on a one-on-one clinical assessment, aided by standardized tests. The overall effectiveness of the program is best assessed using outcome assessment tools. The certification process of AACVPR mandates that the program use outcome data to evaluate its effectiveness (see chapter 12 on certification).

This chapter discusses the timing of outcome assessment, followed by a discussion of AACVPR-required patient-centered outcomes as well as other outcomes that may be of interest to programs. It should be noted that some patient-centered outcome measures may not be appropriate for all respiratory disorders. However, AACVPR-required patient-centered outcome measures have been reported as valid and reliable for patients with COPD and interstitial lung disease (ILD). For instance, some health-related quality of life questionnaires have been validated only for COPD and ILD, and their use in other diseases has not yet been described in the literature. Therefore, patients with conditions other than COPD or ILD may need different outcome assessments. Some of these outcome assessments are discussed in further detail in chapter 8.

TIMING AND ANALYZING OUTCOMES

Outcome assessment requires a minimum of two time points: one before pulmonary rehabilitation (baseline) and one immediately after completing rehabilitation. Optional postrehabilitation outcome measurements can also be taken at further intervals such as 3, 6, or 12 months; however, these frequencies are not always practical because some patients are lost to follow-up or may be unwilling to return for testing.

AACVPR program certification requires only a pre- and postrehabilitation measure of outcomes. The pulmonary rehabilitation program must include at least 10 pulmonary rehabilitation sessions within a 3-month period. However, the pulmonary rehabilitation program can run longer than 3 months. Change in performance is generally evaluated by comparing the post–pulmonary rehabilitation program measure with the corresponding baseline measure. Some measures, such as the 6-minute walk test distance, are best expressed by documenting the absolute value (e.g., in feet or meters). For comparison of pre- and post-aggregate outcome data, paired t-tests or nonparametric tests can be used for statistical analysis (1).

The immediate post–pulmonary rehabilitation time, although very practical, may or may not be the best time to evaluate postrehabilitation changes. While improvement may continue well after the program has been completed (2, 3), possibly because patients may take weeks to months to incorporate health behavior changes learned in pulmonary rehabilitation into their everyday lives, a defined time period or number of sessions is recognized for measurement to allow consistent evaluation.

PATIENT-CENTERED OUTCOME MEASURES

Patient-centered outcome measures in pulmonary rehabilitation consist of evaluating an individual’s ability to exercise, symptoms, and health-related quality of life. This section describes the standard outcome measures used in the clinical setting to evaluate pulmonary rehabilitation. Based on published evidence, AACVPR identified a limited set of valid and reliable instruments for each patient-centered outcome, including at least one instrument found in the public domain. Other outcome measures can be used but are often more practical in a research setting. Detailed information on patient-centered outcome measures and valid and reliable instrument descriptions are available to members of AACVPR at the www.AACVPR.org website by searching for “Pulmonary Rehabilitation Outcomes Resource Guide.” This guide is updated regularly by pulmonary rehabilitation experts.

Functional Status and Exercise Capacity

Measures of functional status and exercise capacity range from simple field tests to cardiopulmonary exercise stress tests. The most commonly used field tests of exercise capacity are the 6-minute walk test (4, 5) and the incremental (6) or endurance (7) shuttle walk test (8). Tests used for exercise assessment are discussed in chapter 3.

Symptoms

The most common symptoms experienced by patients with respiratory diseases are dyspnea and fatigue. These can be measured with dyspnea- and fatigue-specific instruments or as domains of other questionnaires. The quality of either sensation can be measured as frequency of occurrence, its intensity, degree of distress it creates, or its impact on activities. For example, the frequency of dyspnea (how many times a day, how many days a week) can be measured by asking the patient to report a frequency score. Intensity of dyspnea is an important outcome during exercise or field testing, using a numerical scale (0 to 10 or 100). While dyspnea intensity is an important tool, this dimension does not reflect the global impact of dyspnea. The distress of dyspnea can be described as “fear of being active” or “fear of worsening breathing,” while the impact of dyspnea can be described as limitation in a particular activity or activities. Dyspnea should be monitored during exercise and its values reported before and after (such as during a walk test) as well as measured before and after rehabilitation (e.g., baseline level of dyspnea before enrolling in rehabilitation and baseline level of dyspnea after completing rehabilitation).

The simplest and most common ways to rate dyspnea intensity during exercise are the Borg CR-10 scale or a numerical rating scale. The Borg CR-10 rating scale (9) is a category-ratio scale. Users should be aware that the Borg CR-10 scale requires permission from the author for use. Equally important is that users understand and accurately follow Dr. Borg’s instructions for correct use of the scale.

A numerical rating scale—the example here is the visual analog scale (VAS) (10, 11)—asks the patient to rate degree of dyspnea on a 100 mm scale (line). Descriptive anchors are included on either end of the scale, with 0 representing no breathlessness and 100 representing greatest breathlessness (refer to figure 3.12). Variations of the scale differ in measured length and use numerical descriptors.

The list of dyspnea outcome measures that can be used to assess symptom changes can be found in table 7.2. Based on the strength of evidence of these instruments and their usefulness in the clinical setting, AACVPR requires one of the following three instruments be used in programs seeking certification: the modified Medical Research Council scale, the University of California, San Diego Shortness of Breath Questionnaire, or the Baseline Dyspnea Index (BDI) and Transition Dyspnea Index (TDI). All these measures evaluate the impact of dyspnea on the performance of activities, while the UCSD scale also measures the distress of dyspnea. Additional optional questionnaires are listed in table 7.2 and in the AACVPR Pulmonary Rehabilitation Outcomes Resource Guide (available at www.aacvpr.org for members). These instruments measure both dyspnea and functional status and include the Pulmonary Functional Status and Dyspnea Questionnaire (PFSDQ) (16), Pulmonary Functional Status and Dyspnea Questionnaire-Modified (PFSDQ-M) (17), and Pulmonary Functional Status Scale (PFSS) (18).

Dyspnea is also measured in respiratory-specific HRQoL questionnaires. The symptom domain of the St. George’s Respiratory Questionnaire (SGRQ) (19) evaluates dyspnea in combination with other symptoms such as cough, sputum, and wheeze. This domain of the SGRQ is therefore not specific to dyspnea. The SGRQ’s activity domain also reflects activity limitations resulting from dyspnea. The dyspnea domain of the Chronic Respiratory Disease Questionnaire (CRQ) (20) evaluates the intensity of dyspnea with five activities the patient identifies as important. The Seattle Obstructive Lung Disease Questionnaire (SOLQ) (21) evaluates several dimensions of dyspnea; however, there is no specific score that captures dyspnea.

All the features of dyspnea (frequency, intensity, impact, and distress) also apply to the symptom of fatigue. Fatigue can therefore be measured with a brief evaluation such as a VAS, substituting the word dyspnea with a comparable word for fatigue (e.g., tiredness, exhaustion). The Borg scale can also be used in this regard with word substitution. Fatigue-specific questionnaires have also been developed to more extensively evaluate fatigue. These questionnaires include the Multidimensional Fatigue Inventory (MFI) (22) and the Multidimensional Assessment of Fatigue (MAF) (23, 24). Fatigue can also be a dimension of other questionnaires, such as the vitality dimension of the SF-36, the fatigue dimension of the CRQ, the fatigue dimension of the PFSDQ-M, and the fatigue/inertia and vigor/activity subscales of the Profile of Mood States (POMS) (25).

Health-Related Quality of Life (HRQoL)

Health-related quality of life scores (also referred to as health status) reflect domains of importance to a patient’s quality of life in the context of a health issue. HRQoL measures can be generic or disease- or condition-specific questionnaires (table 7.3). Scores can be expressed as a total score (i.e., a composite score of several domains) or as individual domain scores. The total score reflects overall quality of life. Most, but not all, HRQoL questionnaires include measures of physical function, symptoms (although not always dyspnea), and emotional function. Reporting of individual component scores is also useful and complementary. For instance, the dyspnea domain of the CRQ can fulfill the requirement for dyspnea assessment, while the total score of this instrument can fulfill the requirement for HRQoL assessment.

Among the disease-specific questionnaires frequently used to evaluate the HRQoL of pulmonary patients are the St. George’s Respiratory Questionnaire (SGRQ), the Chronic Respiratory Disease Questionnaire (CRQ), and the COPD Assessment Test (CAT).

The SGRQ evaluates activities, the impact of disease (social function and psychological disturbance), and symptoms (dyspnea, cough, sputum, and wheeze) (25). As mentioned previously, the symptom domain of the SGRQ is not specific to dyspnea. The SGRQ has been validated for several obstructive lung diseases. A new, shorter version of the SGRQ, the SGRQ-C, is specific only to COPD and is now available, but AACVPR does not recommend the shorter version because, according to the developers, the tools are not equivalent.

The CRQ includes the domains of dyspnea, fatigue, emotion, and mastery (16). The composite (total) score of these domains reflects health-related quality of life. To complete the CRQ dyspnea domain, the patient must identify five dyspnea-producing activities that are important and have caused dyspnea recently, then rate each on a 7-point scale. Although this patient-specific approach in the dyspnea domain increases the CRQ’s ability to detect change after interventions such as pulmonary rehabilitation, it increases its complexity and requires interviewer administration. Subsequently, standardized versions of the CRQ are now available (31-33).

The CAT is an 8-item questionnaire that uses a 6-point Likert-type scale asking questions about cough, mucus congestion, chest tightness, exertional dyspnea, ADL limitation, confidence in leaving the home, sleep quality, and energy level (24). It is scored from 0 to 40, with higher scores indicating greater levels of limitation. The CAT has been initially validated in prospective studies conducted in the United States, Europe, and China but is globally applicable. The CAT U.S. version is available as an educational material download by registering for a free account with the COPD Foundation (www.copdfoundation.org).

The most frequently used non-disease-specific HRQoL measure is the Medical Outcomes Study short form (called the SF-36 because it is made up of 36 questions). This self-administered questionnaire measures general domains of interest in people with health problems. The two major domains are physical and emotional function; several subcategories exist under these domains. These subcategories evaluate symptoms of fatigue as well as limitations in activities and psychological distress. Being a generic instrument, the SF-36 can be used to assess various respiratory diseases and comorbidities. However, it does not address dyspnea, which is a major area of importance to the pulmonary patient.

Other Outcomes of Importance

Numerous other outcomes may be important to measure in pulmonary rehabilitation. Functional performance and home-based activity, psychological outcomes such as anxiety and depression, adherence (dropout or attendance rate), disease-specific knowledge and self-efficacy, smoking cessation, weight modification, health care utilization, mortality, and patient satisfaction are all of interest. Many programs elect to measure several of these outcomes as a means of evaluation.

Functional Performance and Home-Based Activity

The primary purpose of improving a patient’s strength and endurance with exercise training is to enable the patient to engage in daily activities. Although exercise is evaluated as an outcome (e.g., walk distance), the ultimate outcome is to have the patient be more active. The goal is that patients will resume activities they may have abandoned because of dyspnea and increase their level of participation in work, school, social, and recreational activities. Enabling a patient to resume activities after pulmonary rehabilitation is related not just to strength and endurance but also to increased confidence and self-efficacy.

Activity levels can be evaluated with monitoring devices or self-report measures. It is reasonable to use monitoring devices to assess activity before and after pulmonary rehabilitation as an outcome measure, if it is not cost-prohibitive for the program. These devices focus mostly on walking activities and, to a lesser extent, upper-body activities. Functional status questionnaires, on the other hand, evaluate a wide range of activities that reflect changes after pulmonary rehabilitation. Common functional status measures are the PFSDQ, PFSDQ-M, and PFSS, described earlier.

Psychosocial Outcomes

Anxiety and depression are common psychological symptoms in patients with chronic respiratory disease. Questionnaires used to screen for anxiety or depression can help identify patients who need referral for psychological evaluation. Instruments used for psychological screening and assessment are described in chapter 5.

Patient Adherence

Patient adherence, assessed as an outcome, can be used to evaluate program attendance (exercise sessions, education sessions, or both) and dropout rate. Factors that affect adherence include program factors (cost, hours of operation), travel distance, transportation, climate and seasonal variations, and disease exacerbations.

Although it may be valuable to identify patients who have not adhered to pulmonary rehabilitation, there is no consistently identified variable that can determine the likelihood of adherence. Tracking dropouts may provide insight on adherence within individual programs. This can be accomplished by following up with patients about their reasons for withdrawal.

Knowledge and Self-Efficacy

Self-management education during pulmonary rehabilitation improves disease stability and health care utilization (see chapter 4). To document the benefits of such education, patients must demonstrate a change in knowledge. This can be determined by return demonstration or knowledge tests. There are few well-tested measures of knowledge used in pulmonary rehabilitation. Few measures of self-efficacy are available for the patient with chronic respiratory disease. The measure most commonly used for the COPD patient is the COPD self-efficacy scale (34). The psychometric properties, however, are weak for all self-efficacy measures in COPD (35).

Smoking Cessation

Although data are not available, smokers enrolled in pulmonary rehabilitation may reduce their tobacco use or stop smoking as a result of support from the program. Smoking cessation may be used as an outcome measure after pulmonary rehabilitation. Evaluation of smoking can occur by measuring quit rates or number of cigarettes smoked. Some program staff are of the opinion that enrolling smokers may adversely affect former smokers. There are no data to support this contention. On the other hand, pulmonary rehabilitation is the ideal time for patients to stop smoking because of the education and support offered by the program.

Weight Modification

Changes in weight or body composition can occur during pulmonary rehabilitation. For some, weight loss may be a desired goal, and for others, weight loss may be problematic. Weight loss may reflect a change in distribution of fat mass, or the loss may indicate increasing malnutrition and muscle loss. Weight gain can therefore be an intentional objective for some patients. Body weight, body mass index (BMI), or other measures of body composition can be used as outcome measures before and after the program.

Health Care Utilization

Chronic respiratory diseases are often complicated by exacerbations associated with an increase in symptoms and a decline in functional status. Exacerbations often require escalation of medical care. Patients with frequent exacerbations are considered candidates for pulmonary rehabilitation referral. The self-management education and exercise in pulmonary rehabilitation can help stabilize the disease. Unplanned office or emergency room visits, hospitalizations, and duration of hospitalizations are all outcomes that can be studied to assess the impact of pulmonary rehabilitation on exacerbations.

Mortality

Higher levels of dyspnea and greater impairments in exercise capacity, functional status, and quality of life have been shown to predict mortality in groups of patients with chronic obstructive pulmonary disease (36-41). Pulmonary rehabilitation has not been convincingly shown to affect survival; available studies are small and often underpowered to demonstrate a survival benefit (42, 43). Since pulmonary rehabilitation has proven of benefit in each of the outcome areas listed previously, it is reasonable to assume it may favorably affect survival in a reasonably powered clinical trial.

Patient Satisfaction

Patient satisfaction surveys can clarify issues that potentially influence program success and patient adherence. These surveys can also help programs modify their content according to the needs of the participants. Brief postrehabilitation questions can target the areas of satisfaction by simply asking the following: Are you satisfied with the pulmonary rehabilitation program? Are you satisfied with the exercise program? Are you satisfied with the education component? Do you think you benefited from the program? Would you recommend the program to others? The answers will provide information about patient satisfaction.

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