Abstract
Objective
To assess the construct validity of the Self-Administered Comorbidity Questionnaire
(SCQ) in patients with systemic sclerosis (SSc) and systemic lupus erythematosus (SLE).
Methods
The SCQ was modified for the SSc cohort to emphasize the objective of recording problems
other than the patients' scleroderma. It was administered to 406 SSc and 147 SLE patients. Construct
validity of the SCQ was evaluated separately in the SSc and SLE cohorts by testing
the hypotheses that a valid comorbidity index should correlate with age and health-related
quality of life (Medical Outcomes Trust Short Form 36 [SF 36]) but not with disease-specific
variables.
Results
The SCQ score correlated with age in the SSc patients only (Tau B=0.37, P<0.001) and not in the SLE patients. It correlated with the SF 36 in both SSc and SLE.
However, it also correlated with several disease-related variables. There was significant
overlap between reports of comorbidities and disease-related problems in the SSc cohort.
Conclusion
Patients with systemic autoimmune diseases cannot distinguish true comorbidities from
conditions related to their index disease and, as such, a self-administered comorbidity
questionnaire does not appear useful in these diseases.
Keywords
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References
- The pre-therapeutic classification of co-morbidity in chronic disease.J Chronic Dis. 1970; 23: 455-468
- Flaws in mortality data. The hazards of ignoring comorbid disease.JAMA. 1988; 260: 2253-2255
- A new method of classifying prognostic comorbidity in longitudinal studies: development and validation.J Chronic Dis. 1987; 40: 373-383
- Aging in the eighties: the prevalence of comorbidity and its association with disability.in: Advance data from vital and health statistics. National Centre for Health Statistics, Hyattsville, MD1989
- Prevalence, expenditures, and complications of multiple chronic conditions in the elderly.Arch Intern Med. 2002; 162: 2269-2276
- Persons with chronic conditions. Their prevalence and costs.JAMA. 1996; 276: 1473-1479
- Multimorbidity and quality of life in primary care: a systematic review.Health Qual Life Outcomes. 2004; 2: 51
- The importance of co-existent disease in the occurrence of postoperative complications and one-year recovery in patients undergoing total hip replacement. Comorbidity and outcomes after hip replacement.Med Care. 1993; 31: 141-154
- Problems of comorbidity in mortality after prostatectomy.JAMA. 1992; 267: 1077-1082
- The risk of adjustment.Med Care. 1992; 30: 973-975
- A comparison of interview data and medical records for previous medical conditions and surgery.J Clin Epidemiol. 1989; 42: 1207-1213
- Can comorbidity be measured by questionnaire rather than medical record review?.Med Care. 1996; 34: 73-84
- Self-reports and general practitioner information on the presence of chronic diseases in community dwelling elderly. A study on the accuracy of patients' self-reports and on determinants of inaccuracy.J Clin Epidemiol. 1996; 49: 1407-1417
- The Self-Administered Comorbidity Questionnaire: a new method to assess comorbidity for clinical and health services research.Arthritis Rheum. 2003; 49: 156-163
- Quantifying comorbidity in a disease-specific cohort: adaptation of the total illness burden index to prostate cancer.Urology. 1999; 54: 424-429
- Starting insulin therapy in patients with type 2 diabetes: effectiveness, complications, and resource utilization.JAMA. 1997; 278: 1663-1669
- Skin thickness score in systemic sclerosis: an assessment of interobserver variability in 3 independent studies.J Rheumatol. 1993; 20: 1892-1896
- Use of a numerical rating scale as an answer modality in ankylosing spondylitis-specific questionnaires.Arthritis Rheum. 2002; 47: 242-248
- Reliability of pain scales in the assessment of literate and illiterate patients with rheumatoid arthritis.J Rheumatol. 1990; 17: 1022-1024
- Measurement of patient outcome in arthritis.Arthritis Rheum. 1980; 23: 137-145
- The value of the Health Assessment Questionnaire and special patient-generated scales to demonstrate change in systemic sclerosis patients over time.Arthritis Rheum. 1997; 40: 1984-1991
- European multicentre study to define disease activity criteria for systemic sclerosis. II. Identification of disease activity variables and development of preliminary activity indexes.Ann Rheum Dis. 2001; 60: 592-598
- European Scleroderma Study Group to define disease activity criteria for systemic sclerosis. III. Assessment of the construct validity of the preliminary activity criteria.Ann Rheum Dis. 2003; 62: 901-903
- A disease severity scale for systemic sclerosis: development and testing.J Rheumatol. 1999; 26: 2159-2167
- Assessment of disease severity and prognosis.Clin Exp Rheumatol. 2003; 21: S42-S46
- Aids to the examination of the peripheral nervous system.in: Memorandum no. 45. Her Majesty's Stationary FOffice, 1976
- The relationship between disease activity and expert physician's decision to start major treatment in active systemic lupus erythematosus: a decision aid for development of entry criteria for clinical trials.J Rheumatol. 1998; 25: 277-284
- Systemic lupus erythematosus disease activity index 2000.J Rheumatol. 2002; 29: 288-291
- The development and initial validation of the Systemic Lupus International Collaborating Clinics/American College of Rheumatology damage index for systemic lupus erythematosus.Arthritis Rheum. 1996; 39: 363-369
- The MOS 36 item short-form health survey (SF-36). I. Conceptual framework and item selection.Med Care. 1992; 30: 473-483
- SF-36 Health Survey: Manual and interpretation guide.The Health Institute, New England Medical Center, Boston, MA1993
- Cross-cultural adaptation of health-related quality of life measures: literature review and proposed guidelines.J Clin Epidemiol. 1993; 46: 1417-1432
- Health measurement scales—A practical guide to their development and use.2nd edition. Oxford University Press, Oxford1996
- Use of comorbidity scores for control of confounding in studies using administrative databases.Int J Epidemiol. 2000; 29: 891-898
- Correlation of the degree of dyspnea with health-related quality of life, functional abilities, and diffusing capacity for carbon monoxide in patients with systemic sclerosis and active alveolitis: results from the Scleroderma Lung Study.Arthritis Rheum. 2005; 52: 592-600
- Multimorbidity in general practice: prevalence, incidence, and determinants of co-occurring chronic and recurrent diseases.J Clin Epidemiol. 1998; 51: 367-375
- How to measure comorbidity. A critical review of available methods.J Clin Epidemiol. 2003; 56: 221-229
- Development and testing of a systemic lupus-specific risk adjustment index for in-hospital mortality.J Rheumatol. 2000; 27: 1408-1413
- Short-term prediction of mortality in patients with systemic lupus erythematosus: classification of outcomes using random forests.Arthritis Rheum. 2006; 55: 74-80
Article info
Publication history
Published online: March 17, 2008
Accepted:
August 3,
2007
Identification
Copyright
© 2008 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
