SF-12
Assessment of physical and mental health status
The Short Form 12 Health Survey is a validated 12-item-tool for generic evaluation of patient quality of life. Over eight different domains, it evalues general physical and mental health status. It is the shorter version of the SF-36 questionnaire.
The questionnaire items in the SF-12 span several domains, including physical functioning, physical role, general health, energy/fatigue and mental health. The results are tabulated as two scores – one physical component and one mental component. As a non-disease-specific tool, the SF-12 is suitable for general populations and has thus found application in disciplines like orthopedics, cardiology and neurology.
Indication
Generic evaluation of patients physical and mental health status is the primary goal and indication of the SF-12.1, 2 Due to its generalizibility, the tool has already found application in several medical subdisciplines.
In the context of orthopedics, studies evaluating the effects of osteoarthritis and musculoskeletal disease, and cervical spine surgery on overall patient quality of life have used the SF-12.3, 4
In other medical subdisciplines, the questionnaire has been administered to patients with myocardial infarction (cardiology) and neurological patient groups with stroke.5, 6
Items - Dimensions - Completion time
The SF-12 includes 12 items with multiple-choice questions. The number of possible response options varies from 2 to 6. Only one answer can be selected.
The questionnaire covers various dimensions. The scope includes the domains of physical functioning (2 questions), physical limitations in daily activities (2 questions), bodily pain (1 question), general health (1 question), energy/fatigue (1 question), social functioning (1 question), emotional limitations in daily activities (2 questions) and mental health (2 questions).
It takes less than 2 minutes to complete the SF-12 for the majority of individuals.7
Scoring method
The results of the SF-12 health survey are represented by one physical component score (PCS) and one mental component score (MCS), with the PCS including the items inquiring parameters of physical functioning and pain, while the MCS focuses on psychological and mental health questions.7
A norm-based scoring leads to scores where 50 represents the average in comparison with the American reference population. The standard deviation is 10 (a score of 60 means one standard deviation above the US average). Every answer is linked with an indicator variable and different regression weights during the score calculation. The patients answers can be send to qualitymetric.com, where an API scores the raw data.
Score interpretation
Higher values are linked with a better health status, while lower values depict a worse health status.
The score is based on normally distributed statistical values with 50 as the mean value and 10 as the standard deviation. Additionally, an individual interpretation of every single question is possible.
qualitymetric.com; Johnston, Rhode Island, United States of America11
A license needs to be requested, so costs are to be expected.
The SF-12 is generalizable enough to be applicable in diverse patient populations. Moreover, the PCS and MCS scores were shown to be identical in an comparison study with the longer SF-36 survey.12
Due to its brevity, it can be conducted quickly and is therefore easy to implement in routine clinical practice. The end score is statistically intuitive to interpret.
The scoring system is complicated and takes a longer time in comparison to other questionnaires.
Additionally, high rates of missing data have been observed. This represents a a severe complication because interpretation with missing answers is impossible.13
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References
Foley, Amanda, et al. “Does hydrotherapy improve strength and physical function in patients with osteoarthritis—a randomised controlled trial comparing a gym based and a hydrotherapy based strengthening programme.” Annals of the rheumatic diseases 62.12 (2003): 1162-1167.
Gandhi, Sanjay K., et al. “Psychometric evaluation of the 12-item short-form health survey (SF-12) in osteoarthritis and rheumatoid arthritis clinical trials.” Clinical therapeutics 23.7 (2001): 1080-1098.
Godil, Saniya S., et al. “Accurately measuring the quality and effectiveness of cervical spine surgery in registry efforts: determining the most valid and responsive instruments.” The Spine Journal 15.6 (2015): 1203-1209.
Carmona, Loreto, et al. “The burden of musculoskeletal diseases in the general population of Spain: results from a national survey.” Annals of the rheumatic diseases 60.11 (2001): 1040-1045.
Mols, Floortje, Aline J. Pelle, and Nina Kupper. “Normative data of the SF-12 health survey with validation using postmyocardial infarction patients in the Dutch population.” Quality of Life Research 18.4 (2009): 403-414.
Ellis, Charles, Anouk L. Grubaugh, and Leonard E. Egede. “Factors associated with SF-12 physical and mental health quality of life scores in adults with stroke.” Journal of Stroke and Cerebrovascular Diseases 22.4 (2013): 309-317.
Ware, J. E., M. Kosinski, and S. Keller. “SF-36 physical and mental health summary scales.” A user’s manual (2001): 1994.
Gandek, Barbara, et al. “Cross-validation of item selection and scoring for the SF-12 Health Survey in nine countries: results from the IQOLA Project.” Journal of clinical epidemiology 51.11 (1998): 1171-1178.
Wirtz, Markus Antonius, et al. “Konfirmatorische Prüfung der Skalenstruktur des SF-12 Version 2.0 in einer deutschen bevölkerungs-repräsentativen Stichprobe.” Diagnostica (2017).
Jenkinson, Crispin, and Richard Layte. “Development and testing of the UK SF-12.” Journal of health services research & policy 2.1 (1997): 14-18.
https://www.qualitymetric.com/
Jenkinson, Crispin, et al. “A shorter form health survey: can the SF-12 replicate results from the SF-36 in longitudinal studies?.” Journal of Public Health 19.2 (1997): 179-186.
Morfeld, Matthias, et al. “Der SF-12–Das Problem der Missing Data.” Diagnostica 49.3 (2003): 129-135.
https://loinc.org/71934-4/