Background & Aims

Chronic shoulder pain is a a high prevalence dysfunction, ranging from 6.9% to 26%, being one of the most common musculoskeletal conditions in primary healthcare. This condition generates higher costs related to occupational injuries each year .Economic evaluations are an important to better address limited resources to approaches that can improve the quality of life of a population.The Sf-12 is an instrument designed to evaluate health-related quality of life; The information provided by this instrument allows the calculation of Quality-Adjusted Life Years (QALYs). Cost-utility analysis utilizes the QALYs as clinical outcome since it facilitates comparisons across different interventions and health conditions. The measurement properties of the SF-12 weren’t analyzed in this specific population in Brazil. The aim of this study is to test the reliability, measurement error, and construct validity of the SF-12v1 and SF-12v2 in Brazilian patients with chronic shoulder pain

Methods

Patients over 18 years old, of both sexes, experiencing shoulder pain for more than three months were recruited. Data collection occurred at two time points, with a one-week interval, guiding patients in self-completing the instruments. Two versions of SF-12, SPADI, and a Global Perception Scale (GPE) were applied. Reliability for final score of the SF-12 Physical Component Score (PCS) and Mental Component Score (MCS) was assessed through the ICC and a 95% CI. Measurement error for the PCS and MCS was calculated by the percentage of agreement, with values established from the standard error of measurement (SEM) and minimal detectable change (MDC), very good: ?5%; good: >5% and ?10%; doubtful: >10% and ?20%; and poor: >20%. Construct validity was assessed using the Spearman correlation test between thefinal scores of the SF-12v1, Sf-12v2, SPADI, and GPE, with values considered weak correlation (r<0.30), moderate (r?0.30 or r<0.60), and strong (r?0.60).

Results

This partial analysis encompasses data from 34 participants (24 females and 10 males) who consented to the informed consent form and completed the questionnaires. The average age of the participants was 54.1 (± 5.6), with an average of 24 months of pain duration. Physical and Mental Component Summary scores of SF12v1 and SF12v2 demonstrated excellent reliability levels (0.85, 0.91, 0.97, 0.97 respectively). The measurement error of the PCS and MCS of the SF12v1 and SF12v2, was considered very good (?5%) and good (>5% and <10%). Construct validity demonstrated week and strong correlation between the PCS And MCS of the versions of the SF-12 (r=0.08 to 0.83). Both versions of the SF-12 demonstrated weak correlation with the SPADI (r=0.04 to 0.21). The GPE and PCS and MCS of both versions of the SF-12 demonstrated weak correlations (r=0.05 to 0.13). The correlation between SPADI and GPE was weak for the disability dimension (r=0.24) and moderate for the pain dimension (r=0.36).

Conclusions

The Physical and Mental Component Summary scores of SF12v1 and SF12v2 demonstrated excellent reliability and a very good to good agreement in the measurement error. The construct validity demonstrated high correlations for the Physical Component Score of the two versions of the SF12, and for the Mental Component Score, but not for the spearman test between the PCS and MCS. What can be explained by the emphasis of the questions that compose the final scores, the PCS focusing more on the relation of the physical health and the quality of life and the MCS exploring the mental health aspect. The SPADI an GPE correlations with the final scores of the SF12 demonstrated to be weak, with values not exceeding 0.21. These results can help future studies to better formulate hypothesis for the correlation between these instruments.

References

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Presenting Author

Vinícius Sacioti Vaz

Poster Authors

Vinícius Sacioti

Master's student

University of São Paulo

Lead Author

Gisela Cristiane Miyamoto

Universidade Cidade de São Paulo

Lead Author

Gisele Harumi Hotta; Phd

Universidade Cidade São Paulo (UNICID), São Paulo – SP

Lead Author

Maria Eduarda Francelino; Graduation Student

School of Medicine of Ribeirão Preto, University of São Paulo

Lead Author

Anamaria Siriani de Oliveira

Universidade de São Paulo

Lead Author

Topics

  • Economics, Ethics, and Law