Abstract
Objectives: To study patients with ALS to determine the following: 1) the relationship between physical function and quality of life (QOL); 2) the instruments that best reflect patients’ own ratings of QOL; and 3) whether spiritual/religious factors play a role in determining QOL.
Methods: The authors prospectively studied 96 patients with ALS using several instruments, including the McGill Quality of Life (MQOL) instrument, the Idler Index of Religiosity, the Sickness Impact Profile (SIP)/ALS-19, and several measures of strength and physical function.
Results: QOL as assessed by patients (MQOL single item score) did not correlate with measures of physical function and strength, but correlated with the total MQOL score (p < 0.0005), the psychological and existential subscores of MQOL (p < 0.0005), the support subscore of MQOL (p = 0.001), and the total Idler score (p = 0.001). In contrast, correlations between SIP/ALS-19 and these measures were not significant, although SIP/ALS-19 correlated with measures of physical function and strength.
Conclusions: QOL, as assessed by the patient with ALS, does not correlate with measures of strength and physical function, but appears to depend on psychological and existential factors, and thus may be measured well by the MQOL scale. Spiritual factors and support systems appear to play roles as well. SIP/ALS-19 is a good measure of physical function, but not of overall QOL.
There is no consensus on which instruments are most suitable for measuring quality of life (QOL) in patients with ALS. It has been suggested that most QOL instruments overemphasize the physical domain and do not adequately assess the existential domain (perception of purpose, meaning in life, capacity for personal growth).1 For example, a shortened version of the Sickness Impact Profile, the SIP/ALS-19, has been chosen as a measure of QOL in the national ALS Patient Care Database.2,3 However, scores on the full SIP and on shortened versions correspond closely to measurements of strength and function as determined by the Tufts Neuromuscular Quantitative Examination.3,4 Because of this, these instruments are heavily weighted toward physical function, and would be expected to inevitably decline over time as patients lose their physical abilities. It has been suggested that a distinction should be made between “health-related QOL” and QOL. The former reflects a patient’s health status and may be measured by instruments that focus on physical health and overall functional ability; the latter takes into account other nonmedical factors.5,6
The McGill Quality of Life questionnaire (MQOL) differs from many other instruments in being less heavily weighted toward physical function and by including an existential domain.1,6-8 It has been validated in patients with cancer and HIV infection, and is believed to be a useful tool for assessing QOL in patients with life-threatening illnesses. Thus, MQOL may be a helpful tool in assessing patients with ALS. Spirituality also may play an important role in determining QOL in patients with ALS beyond the dimensions tapped by the MQOL, yet the role of such factors has not been explored in ALS.
This study was undertaken in an attempt to 1) determine the relationship, if any, between physical function and QOL in patients with ALS; 2) compare several instruments for the assessment of QOL in patients with ALS to determine which ones best reflect patients’ own ratings of QOL; 3) determine whether MQOL is a useful instrument for assessing QOL in ALS patients, and whether it is superior to other instruments; and 4) determine whether spiritual/religious factors play a role in determining QOL in patients with ALS.
Patients and methods.
This was a prospective study of consecutive patients seen at the Hershey Medical Center ALS Clinic. All nondemented patients who met El Escorial criteria9 for definite or probable ALS and who gave informed consent were eligible for the study. The study was approved by the Institutional Review Boards of the Pennsylvania State University and its College of Medicine. At the time of the visit, basic demographic information was collected. All patients underwent the following assessments.
Direct measures of strength and function.
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1. Manual muscle testing was performed on four muscle groups bilaterally (arm abductors, wrist extensors, hip flexors, and ankle dorsiflexors, corresponding to proximal and distal upper and lower extremity muscle groups, respectively) and graded using the Medical Research Council (MRC) scale of 0 to 5.10 A composite MRC score was then obtained by summing these values and dividing by 8. Scores range from 0 (weakest) to 5 (strongest).
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2. ALS Functional Rating Scale score (ALSFRS),11 a 40-point scale consisting of 10 items that assess bulbar, limb, and respiratory function, was obtained. Scores range from 0 (worst function) to 40 (best function).
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3. Forced vital capacity, converted to a percentage of predicted value, was assessed.
Measures of QOL.
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1. With a single question, the patient was asked to rate his or her own QOL (MQOL Single-Item Scale [MQOL-SIS]).1,6-8 Scores range from 0 (very bad) to 10 (excellent).
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2. MQOL—consisting of a total score and five subscores (physical symptoms, physical well-being, psychological, existential, and support), each of which range from 0 (worst) to 10 (best)—was obtained.1,6-8
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3. SIP/ALS-19, determined by weighting each of 19 items as per McGuire et al.,3 was assessed. The total score was normalized to a 100-point scale and then subtracted from 100 so that higher values represented a better level of function. Scores range from 0 (worst) to 100 (best).
Measure of spirituality and religiousness.
The Idler Index of Religiosity was employed.12,13 This is a brief (four-item) instrument that measures two key dimensions of religiosity—organizational and subjective religiosity—which are categorized as public and private religiosity. Total scores range from 4 (least religious/spiritual) to 17 (most religious/spiritual), subdivided into public religiosity (range 2 to 10) and private religiosity (range 2 to 7).
Assessment of the use of other treatments and support services.
Use of the following was determined: feeding tube; noninvasive ventilatory support (bilevel positive airway pressure); riluzole; gabapentin; wheelchair; augmentative communication device; support group for meeting other patients with ALS and their caregivers; in-home care from an agency, organization, or volunteers; hospice care.
Correlations were performed using Spearman’s rho. Because there were a large number of correlations, p < 0.005 was chosen as being significant.
Results.
Ninety-six patients were enrolled. There were 52 men (54.2%) and 44 women (45.8%). Age at onset varied from 23 to 80 years, with a mean of 57.8 years. None was ventilator-dependent. The mean duration of symptoms at the time of data collection was 31.8 months, with a range of 2 months to 10 years.
Results of measures of strength, function, QOL, and spirituality/religiosity are provided in table 1. QOL as assessed by the patients (MQOL-SIS) was, on average, high. The average patient rated QOL as being greater than a 7 on a 1 to 10 scale. Of 96 patients, 51 (53.1%) rated their QOL as 8 or greater, and over one-fourth (26 of 96) rated their QOL as a 9 or 10. This was despite a composite MRC score below 4 in 45 patients (46.9%) and a functional rating scale score below 27 in the same number of patients, indicating that many patients had significant physical limitations. The average score for the support subscale of MQOL was very high.
Measures of strength, function, quality of life, and spirituality/religiosity in patients with ALS
Some correlations are shown in table 2. QOL as assessed by patients (MQOL-SIS) did not correlate with several direct and indirect measures of physical function and strength, including the composite MRC score, the ALSFRS score, the need for a wheelchair, or the need for in-home care. It also did not correlate with the duration of disease, which would be expected to be a rough measure of strength and function, as ALS is a progressive disorder. In contrast, scores on the SIP/ALS-19 correlated with these measures of physical function and strength (p < 0.0005). Not surprisingly, MQOL-SIS did not correlate with the SIP/ALS-19. ⇓
Correlations (Spearman’s rho) between various measures in patients with ALS
There was a strong correlation between MQOL-SIS and the total MQOL score (p < 0.0005), the psychological and existential subscores of MQOL (p < 0.0005), the support subscore of MQOL (p = 0.001), and the total Idler score (p = 0.001). Correlations between the SIP/ALS-19 and these measures did not meet our criteria for significance.
The physical well-being subscale of the MQOL correlated with MQOL-SIS and with the psychological and existential subscales of MQOL (p < 0.0005), but not with the composite MRC score, the ALSFRS score, or with SIP/ALS-19.
Discussion.
Much of the care for patients with ALS must focus on symptom relief, comfort, and psychological support. A goal when caring for such patients should be maintenance or improvement in their QOL. The importance of measuring QOL in ALS patients has been emphasized,14-15 and published guidelines for ALS therapeutic trials recommend QOL assessment.16 We believe the findings here provide some useful information with regard to QOL in ALS patients.
No relationship was found between physical function and QOL as assessed by these patients (MQOL-SIS). The generally high patient assessment of QOL was striking, despite the presence of a terminal illness and decreased measures of strength and function in many patients. Psychological, existential, and support factors appear to play a significant role in determining QOL in these patients, whereas strength and physical function appear to be much less important. This is consistent with literature describing the importance of factors other than physical function in determining patients’ perceptions of QOL, health, and well-being in those with cancer, AIDS, and other life-threatening illnesses.17-22 It is also a pointed reminder that a patient’s perception of QOL often differs from that of care providers and health professionals.23-25 The interaction of physical and nonphysical factors is complex, however. For example, physical well-being, as measured as a subscore of MQOL, appears to depend at least partially upon psychological and existential factors, and not solely upon physical function.
This study supports previous findings demonstrating that SIP/ALS-19 is a good measure of physical function in patients with ALS.3 However, the apparent importance of other factors in determining QOL in these patients raises concerns about its use as a measure of overall QOL in patients with ALS. The MQOL instrument, with its lesser reliance on physical function and its use of psychological, existential, and support subscores, may therefore be a useful tool to measure QOL in these patients. We are in the process of attempting to validate the use of MQOL in patients with ALS by adding another well-researched quantitative measure of QOL. Future studies will also include a qualitative tool to explore further the subjective meaning of QOL in these patients and will explore further the role of spirituality and religiousness. Hopefully, such additional studies will lead to the development of an ALS-specific QOL tool, based on the more general MQOL instrument.
Acknowledgments
Supported in part by a Clinical Management Research Grant from the ALS Association.
Acknowledgment
The authors thank Cynthia Freeman, Holly Kricher, and Jean Packman for their assistance with data collection.
Footnotes
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Presented in part at the 51st annual meeting of the American Academy of Neurology; Toronto, Ontario, Canada; April 1999.
- Received December 9, 1999.
- Accepted April 19, 2000.
References
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