SF-36 normative values according to level of functioning in older women

The 36-item Medical Outcome Study Short Form (SF-36) survey measures health-related quality of life. Age and disease-specific normative values have been published, but a focus on level of functioning may be more meaningful in case of multimorbidity. We estimated normative values for Australian women aged 79-90 years according to levels of functioning.

Data were from 6127 (aged 79-84 in 2005) and 3424 (aged 85-90 in 2011) participants in the Australian Longitudinal Study on Women's Health. Surveys included the SF-36 and information on housing. Record linkage to assessment data for access to the national program for aged care support was used to obtain information on participants' need for assistance with 10 activities. Normative values were calculated for physical component (PCS), mental component (MCS), and subscale scores for subsamples defined by types of assistance needed.

At the ages of 79-84, the mean (95% confidence interval) PCS and MCS values for women not any needing assistance were 37.5 (37.2-37.9) and 53.0 (52.8-53.3) compared to 29.0 (27.8-30.2) and 45.9 (44.4-47.4) for women needing any assistance. At ages 85-90, the corresponding PCS values were 34.9 (34.5-35.4) vs. 28.2 (27.4-29.0) and the corresponding MCS values were 53.2 (52.8-53.6) vs. 48.7 (47.8-49.6). Values were higher for participants living in the community or retirement village vs. nursing homes/hostels. The PCS, MCS and 8 subscale values decreased as the need for assistance with more basic activities increased.

These normative values facilitate meaningful interpretation of SF-36 scores from the perspective of level of functioning.