Abstract
Purpose
The brief pain inventory (BPI) is often used to assess pain and functional interference as a result of pain in cancer patients. Minor improvements or deteriorations in BPI may be statistically significant due to large sample sizes but may not necessarily be clinically relevant. The purpose of this study was to determine the minimal clinically important differences (MCID) in the functional BPI in patients with pain due to bone metastases.
Methods
BPI scores were collected from patients with painful bone metastases who visited the Rapid Response Radiotherapy Program for palliative radiotherapy. Pain and functional interferences scores were also collected monthly for three months. Patients were categorized into “complete or partial response,” “pain progression,” and “indeterminate response” based on their pain scores as recommended by the latest consensus definitions. Anchor-based determination of MCIDs of functional interference scores was calculated by determining the difference between the mean follow-up scores and the mean baseline scores for patients from each of the three response groups. Distribution-based estimates were obtained utilizing 0.2, 0.3, and 0.5 standard deviation (SD) effect sizes and the standard error of measurement. The anchor-based method results were compared with the distribution-based method results.
Results
Statistically significant MCIDs were determined for all of the functional interference items of BPI for patients with “complete or partial response”; whereas, no statistically significant MCIDs in BPI scores could be determined for patients with “pain progression.” Some of the functional interference items of BPI had statistically significant MCIDs for patients with “indeterminate response,” although these were generally smaller than patients with complete or partial response. Using the distribution-based approach, an effect size of 0.5 SD was the closest estimate for determining the MCID for both patients with complete or partial response and those with indeterminate response.
Conclusions
The MCIDs determined for pain improvement were rather large, where as statistically significant MCIDs could not be detected for pain deterioration. Knowledge of MCIDs utilizing the BPI will allow physicians to evaluate the impact of treatment (or no treatment) on a patient’s functional abilities. Knowledge of MCIDs may allow for sample size determination in future clinical trials.
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References
Twycross R, Harcourt J, Bergl S (1996) A survey of pain in patients with advanced cancer. J Pain Symptom Manage 12:273–282
Maringwa J, Quinten C, King M et al (2011) Minimal clinically meaningful differences for the EORTC QLQ-C30 and EORTC QLQ-BN20 scales in brain cancer patients. Ann Oncol 22:2107–2112
Cook C (2008) Clinimetrics corner: the minimal clinically important change score (MCID): a necessary pretense. J Man Manip Ther 16(4):E82–E83
Bedard G, Zeng L, Lam H et al (2012) Meaningful change in oncology quality of life instruments: a systematic literature review. Expert Rev Pharmacoecon Outcomes Res 12(4):475–483
Sloan J, Symonds T, Vargas-Chanes D, Fridley B (2003) Practical guidelines for assessing the clinical significant of health-related quality of life changes within clinical trials. Drug Inform J 37:23–32
Chow E, Hoskin P, Mitera G et al (2012) Update of the international consensus on palliative radiotherapy endpoints for future clinical trials in bone metastases. Int J Radiat Oncol Biol Phys 82:1730–1737
Cella D, Hahn EA, Dineen K (2002) Meaningful change in cancer–specific quality of life scores: differences between improvement and worsening. Qual Life Res 11:207–221
Osoba D, Rodrigues G, Myles J et al (1998) Interpreting the significance of changes in health related quality-of-life scores. J Clin Oncol 16:139–144
Ringash J, O’Sullivan B, Bezjak A, Redelmeier DA (2007) Interpreting clinically significant changes in patient-reported outcomes. Cancer 110(1):196–202
Maringwa J, Quinten C, King M (2011) Minimal important differences for interpreting health-related quality of life scores from the EORTC QLQ-C30 in lung cancer patients participating in randomized controlled trials. Support Care Cancer 19(11):1753–1760
Wu C, Chuang L, Lin K et al (2011) Responsiveness, minimal detectable change, and minimal clinically important difference of the Nottingham extended activities of daily living scale in patients with improved performance after stroke rehabilitation. Arch Phys Med Rehabil 92:1281–1287
Walters S, Brazier J (2003) What is the relationship between the minimally important difference and health state utility values? The case of the SF-6D. Health Qual Life Outcomes 1:4
Norman GR, Sloan JA, Wyrwich KW (2003) Interpretation of changes in health-related quality of life: the remarkable universality of half a standard deviation. Med Care 41(5):582–592
Revicki D, Cella D, Hays R et al (2006) Responsiveness and minimal important differences for patient reported outcomes. Health Qual Life Outcomes 4:70
Acknowledgments
We thank the generous support of Bratty Family Fund, Michael and Karyn Goldstein Cancer Research Fund, Joseph and Silvana Melara Cancer Research Fund, and Ofelia Cancer Research Fund.
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Wong, K., Zeng, L., Zhang, L. et al. Minimal clinically important differences in the brief pain inventory in patients with bone metastases. Support Care Cancer 21, 1893–1899 (2013). https://doi.org/10.1007/s00520-013-1731-9
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DOI: https://doi.org/10.1007/s00520-013-1731-9