Health Status Questionnaire (SF-36)
The Short Form-36 was derived from the General Health Survey of the Medical Outcomes Study by Stewart and colleagues (1988). It is one of the most widely used generic measures of health-related quality of life and has been shown to discriminate between subjects with different chronic conditions and between subjects with different severity levels of the same disease. The SF-36 has also demonstrated sensitivity to significant treatment effects in a variety of patient populations. Population-based normative data on the SF-36 is available for the United States and some other countries as well.
This instrument addresses health concepts that are relevant to MS patients from the patient's perspective. There is no single overall score for the SF-36, instead, It generates 8 subscales and two summary scores. The 8 subscales are: physical functioning, role limitations due to physical problems, bodily pain, general health perceptions, vitality, social functioning, role-limitations due to emotional problems, and mental health. The two summary scores are the physical component summary and the mental component summary.
The SF-36 is one of the components of the MSQLI as well as the MSQOL-54 and was included in these instruments to serve as a generic health-related quality of life measure that could provide a basis for comparison between the MS patients and other populations.
Administration time is approximately 10 minutes.
The SF-36 is a structured, self-report questionnaire that the patient can generally complete with little or no intervention from an interviewer. However, patients with visual or upper extremity impairments may need to have the SF-36 administered as an interview. Interviewers should be trained in basic interviewing skills and in the use of this instrument.
The scoring system for the SF-36 is relatively complex and generates subscale scores for physical functioning, role limitations due to physical problems, bodily pain, general health perceptions, vitality, social functioning, role-limitations due to emotional problems, and mental health. Two summary scores can also be derived from the SF-36: the physical component summary and the mental component summary.
The SF-36 is easy to administer, covers a broad range of domains of health-related quality of life, and is among the most widely used of such measures. Availability of population-based normative data makes the SF-36 useful for comparative purposes. The availability of several subscales may be useful to investigators interested in testing hypotheses concerning these different areas of function. Because the SF-36 is a generic measure, investigators studying MS may want to augment the SF-36 with other measures that tap ways in which MS more specifically affects quality of life such as fatigue, cognition, vision, etc. the MSQLI and MSQOL-54.provide these types of MS-specific assessments.
In an MS population, the Cronbach's alphas for the various subscales of the SF-36 range from .67 to .94. There is considerable evidence for the validity of the SF-36 in a variety of populations including MS. (Vickrey et al, 1995) In Vickrey's study, the physical functioning and role limitations due to physical problems subscales were the ones that best discriminated between MS patients and the normative U.S. population. In the field testing of the MSQLI, the physical functioning subscale of the SF-36 correlated very highly with both the EDSS and the Ambulation Index.