Two disease-specific questionnaires focus on quality of life for patients undergoing CPAP treatment for sleep apnea.
by Bill McGovern
The very nature of CPAP treatment makes measuring the benefits of CPAP to sleep apnea patients difficult. Studies document its advantages, but many patients struggle with the therapy. “If patients didn’t have to use it, they’d rather not, and they’d give it up tomorrow if there was something better,” says Ward Flemons, MD, FRCPC, medical director at the Alberta Lung Association Sleep Centre at Foothills Hospital in Calgary, Alberta, Canada.
The Calgary sleep center sees 1,200 new referrals a year, 80 percent of whom are sent for treatment or diagnostic testing for apnea. With a very active, 900 member-strong, patient support organization at the hospital, Flemons and colleague Marlene Reimer, RN, MN, PhD, had a good pool of available apnea patients to test quality of life issues related to apnea and its treatment.
According to Flemons, however, traditional quality of life indices or instruments like the SF-36, the sickness impact profile scale, the Nottingham profile scale, or the functional impact profile scale offered little in the way of revealing good information about patients at the sleep center. “It’s fine to quote results from the SF-36 and from the sickness impact profile, but if you actually look at the questions and the way they are asked, they aren’t particularly applicable to the patients that I see in my practice,” he says.
Traditional outcomes measurement questionnaires were designed to look at function in general, according to Terri Weaver, PhD, RN, CS, FAAN, associate professor at the University of Pennsylvania School of Nursing, Philadelphia. “They were not specifically designed for sleep apnea. They were designed to look at activities of daily living,” she says.
Quality of Life Index
Using such tools enables cross-illness comparisons, according to Weaver, but provides little information about specific diseases. Sleep research is only the newest area for which disease-specific tools like Weaver’s Functional Outcomes for Sleep Questionnaire and the Calgary Sleep Apnea Quality of Life Index (SAQLI), developed by Flemons and Reimer, are being designed to gather more pertinent quality of life information about sleep apnea. Weaver’s questionnaire was published in Sleep in 1997; the SAQLI was published in the American Journal of Respiratory Critical Care Medicine in 1998. (The SAQLI questionnaire is also available on the World Wide Web at http://www.QLMed.org/SAQLI/index.html).
Weaver, whose past research is in outcomes for pulmonary COPD, says that the more generic functional measures were a first step in collecting some genuine patient outcomes data. Most have been applied in research to describe functional impairment that results from a disease or condition; less research has been done on outcomes following treatment. The cross-illness advantages of tools like the SF-36 are now being enhanced with more disease-specific questionnaires. “You can probe more deeply into those areas of a patient’s daily life that are impaired by a particular illness,” Weaver says.
Without a single question related to sleep on any available questionnaire, Flemons and Reimer set out to create their own at the Calgary sleep center. “We needed to start from scratch and find out what was actually important to sleep apnea patients,” Flemons says of SAQLI’s development.
Fifty patients and their spouses or partners made up five focus groups that were formed to discuss the impact of sleep apnea and CPAP treatment on their quality of life. The team agreed that the nature of CPAP clearly represented a detriment, “even though their quality of life was being improved in some areas with treatment,” Flemons says.
Focus group participants discussed the most common and troubling symptoms of sleep apnea and those symptoms related to CPAP, dental appliances, or surgery, “because they’re all somewhat unique,” Flemons says.
Semistructured 2-hour interviews with 40 apnea patients who had been treated with nasal CPAP were also conducted to evaluate its adverse effects.
Out of the focus groups and interviews emerged a list of 133 daily functioning items that were significant to sleep apnea patients. Among the daytime sleepiness, fatigue, and nighttime breathing and sleep issues related to sleep apnea were 24 symptoms directly related to CPAP. These symptoms included headaches; runny or dry nose; soreness in airway passages, the jaw, and face; and issues with mask and equipment discomfort.
By approaching sleep apnea directly, Flemons says the team also needed to evaluate the way questions were asked based on the symptoms of the disease and its treatment. “A lot of quality of life questionnaires or functional assessment questionnaires ask whether you can do something or not,” he says. “Our patients clearly told us that it wasn’t a question of whether they could do a task; it was how much energy it took and how much energy they had left to do something else.”
According to Weaver, the very stem of the question shifts much closer to the disease. “The stem of the question doesn’t just ask, ‘Are you able to do a task?’ It asks, ‘Are you able to do a task when you’re sleepy or tired?’ ” she says. Questions on the Functional Outcomes for Sleep Questionnaire, which differs somewhat from SAQLI in its approach, target functioning issues related to sleepiness. “It’s specific to those illnesses where the key symptom is daytime sleepiness,” Weaver says.
The Calgary SAQLI questionnaire is divided into five domains of 35 questions that cover issues regarding daily functioning, social interactions, emotional functioning, symptoms due to apnea, and symptoms related to CPAP treatment. Questions in the first three domains are stated in degrees of frequency or difficulty and probe “how much of a problem” particular tasks are to perform, and “how often” and “how much” symptoms interfere with daily activities, emotional states, and personal relationships. In the symptom domains, patients select the top five symptoms they experience related to apnea (from a list of 21) and CPAP treatment (from a list of 26).
Answer options follow a three-color coding system (yellow, green, and red), and are phrased in amount of time, and the size of a problem. The color coding is designed so the patient or the interviewer does not get confused. “The colors reflect what we call the stem of the question and how a question is phrased,” Flemons says. “The colors distinguish questions by how the questions are asked.”
The SAQLI’s scoring system is a more established method used in many disease-specific questionnaires and was developed by experts at McMaster University in Hamilton, Ontario. But the SAQLI is unique in that treatment-related symptoms of apnea are considered in determining what Flemons calls the net versus treatment benefits of CPAP.
“Scores from the first four domains represent positive things for improvements in daily functioning, social interaction, symptoms, or emotional functioning,” he says, and are tallied as one score. For anybody who has had treatment, a CPAP-related score is subtracted from a total of the other four domains. “The patient’s total benefit score from the first four domains is knocked down a notch with the treatment symptom score to give us what we call the patient’s net benefit,” Flemons says.
In order to formulate the items and issues to be included in the SAQLI questionnaire, the Calgary team identified the last 300 patients who underwent polysomnography in the sleep laboratory, and from these excluded patients who were diagnosed with a disorder other than sleep apnea. A random sampling of 100 of the remaining patients were asked to participate in evaluating the 133 items in the questionnaire. Generally, the questions focused on whether there was a problem; how important the problem was to their quality of life; and if they had undergone treatment, how much had the symptoms improved. Apnea patients who had been treated were asked 24 additional questions related to CPAP.
From this phase of development, a frequency-importance product was tallied for items; the highest scores typically related to problems with alertness, concentration, and the feeling that extraordinary effort was needed to complete an activity. A majority of patients also reported that their snoring or sleep apnea impacted their relationships significantly. Treated patients were asked how much improvement they had experienced in a particular problem following treatment.
Items with the highest frequency-importance rating were included in a final questionnaire that was then tested on 24 newly diagnosed sleep apnea patients who were starting home CPAP treatment. This phase was to determine if questions and instructions were easily understood by patients, if a complete range of responses was provided, and if items were responsive to change following a 4-week CPAP trial.
Flemons points out that the development of SAQLI sheds light on ranking similarities in symptoms across different levels of sleep apnea, as well as among snorers; a sample of snorers who were referred from the office of an otolaryngologist was selected at random to evaluate the 133 items. “We didn’t actually study the snorers,” Flemons says, “and certainly some of them would have had sleep apnea and others wouldn’t.”
However, as a group, the patients who presented to the otolaryngologist did not have as serious complaints as the group that came into the sleep laboratory for treatment of diagnosed sleep apnea, according to Flemons. “Quality of life for snorers wasn’t as affected,” he says, “but when we looked at which aspects of quality of life were affected among people with just simple snoring, those issues were about the same as those mentioned by sleep apnea patients; they just weren’t as severe.” It gave the team confidence that the SAQLI questionnaire could be used as an outcome measure for those who snore, as well.
Testing With Samples
Weaver insists that the value of quality of life instruments like the SAQLI and the Functional Outcomes for Sleep Questionnaire needs to be tested with a number of samples to confirm their validity in deriving good quality of life information about apnea patients and treatment. “As with any new field, you start with a broad range of outcomes that you think would most likely be affected, and then you conduct a series of tests to explore the possibilities that those outcomes will be achieved,” she says. “As time goes on, those outcomes that are more sensitive begin to emerge.”
A lot of the results depends on the sample that is tested, Weaver says, as well as the severity of the illness and the sample size. “So, it’s very hard to compare from study to study, because some of those factors might have been very different and the measures used might have been different,” she says. The outcomes tools that have been consistently responsive across the board will eventually reveal themselves, she insists, adding, “I don’t think the field has yet identified the more salient outcomes that need to be used.”
Once the SAQLI questionnaire was formalized, the Calgary team put it to use, just completing a 3-year clinical trial using the questionnaire to test apnea treatment action. “We tried to evaluate different ways of titrating CPAP at home, compared with titrating CPAP in the sleep lab,” Flemons says. “We wanted to find out whether this had any impact on patients’ perceived quality of life.”
The Calgary team studied three different groups and looked at them prior to and following CPAP treatment, focusing on the improvement that patients documented on the questionnaire. “We really wanted to know whether one group was getting better improvement in quality of life than another group,” he says. The three groups included one that was in the lab getting treatment, another that went home with an automatic CPAP machine that regulated pressure, and a third group–“a sort of cheap way of doing it,” according to Flemons–for which clinicians guessed at a pressure and had spouses determine whether that was a good guess based on whether the patient was still snoring.
Now that the comparisons are complete, the sleep center is excited about the prospects of the SAQLI questionnaire, and the group gets a couple of requests a month from others who want to use it.
Weaver says that more and more attention is now being focused on creating disease-specific questionnaires, mostly because treatment outcomes need to be measured. The benefit of disease-specific questionnaires, she says, is that they can be paired with more traditional functional assessments to provide a more complete portrait of quality of life issues for apnea patients. “It’s a benefit in research and even in clinical practice, depending on your goals, to use a generic functional status measure with a disease-specific quality of life or functional measure,” Weaver says. “With one you get breadth and with the other you get depth.”
Bill McGovern is a contributing writer for RT.